A snippet on habituation

Habituation is one of those terms habitually (see I did it again) used in training and experimental protocols. Trouble is, it is so overused and underdefined that its significance has been frayed at the edges, and is used by most as a term that means having gotten used to something.

Whether you are training horses, dogs or rats, or working with these in laboratory or field experiments, the importance of habituation is underestimated in most cases.

Some proponents define habituation as a waning of response to repeated presentations of a single stimulus, while others would argue that it would only be so if the stimulus was not followed by a second reinforcing or punishing stimulus.

It is almost as if depending on your worldview and the justification you need for your methods or protocols, habituation per se would acquire a distinct definition in almost every case. Having said that most definitions are simplistic and vague in that they do not provide enough information for anyone to differentiate habituation from other phenomenon in which a waning of response is sought.

Habituation is a widespread occurrence, observed across phyla, from single cell organisms capable of behaviour, to mammals. The strikingly different neural and biochemical circuitry of the animals in which habituation has been described, underlie an elemental and nearly ubiquitous  form of biological plasticity , primal for survival and reproductive success in the majority of behaving organisms.

This same ubiquitousness however has led many to synonymously use the term instead of others whose underlying common denominator is a waning of response to repeated stimulus presentations such like acclimatization, accomodation, negative adaptation, desensitization, sensory or motor fatigue, extinction, or even inhibition, to name a few.

Even great trainers, that use scientifically backed knowledge are liable for mistakes in this sense. Let us take the example of this passage from the book; “Don’t Shoot the Dog” (Pryor, 2008), wherein habituation is used synonymously with the term extinguish, as follows:

“Habituation is a way to eliminate unconditioned responses. If a subject is exposed to an aversive stimulus that it cannot escape or avoid, and which nothing it does has any effect on, eventually its avoidance responses will extinguish.” (Pryor, 2008: p.121)

Going back to the passage from “Don’t Shoot the Dog” provided above, a closer look at the explanation of how habituation was apparently attained by exposure to aversive stimuli without possibility of escape, can equally refer to animals in a state of learned helplessness (Pryor, 2002: p.67)as explained in the very same book.

Furthermore according to Seligman (1992: p. 9) learned helplessness is “(…) a psychological state that frequently results when events are uncontrollable.” That is to say that if nothing the animal does can help it escape or avoid the aversive stimuli it plunges into learned helplessness.

All this is discussed in more detail in the Thesis I presented for the fullfilment of my obligations toward the Ethology Institute, and you can read the full thesis free online by following this link:

Habituation: An Ethological Approach

 

 

Herding behavior

Similar to  herdsmen or shepherd dogs herding their flocks of sheep, stallions herd or drive conspecifics  controlling their direction and speed, and this is usually referred to as herding or driving behavior (Tyler, 1972; Feist & McCullough, 1976; Lucy Rees, 1986; McDonnell, 2003).

Stallions have been observed to adopt a species specific herding posture (Berger, 1986) characterized by lowering their heads, stretching out their necks, pinning back their ears, and moving forward toward the targeted conspecifics. If we breakdown the herding posture to its component parts we would find a conglomerate of behaviors which may be interesting to consider on their own. The pinning in a backward direction of the ears, or Ears Laid Back (McDonnell, 2003), or Ears Retracted (Berger, 1986), is typical of a threat posture or expression (Tyler, 1972) as is the Head Threat (McDonnell, 2003) in which the head is pointed forward with neck extended and it is usually associated with agonistic encounters.

The targeted individuals typically responded by moving in the opposite direction from which the stallion was approaching. According to Tyler (1972), ocassionally the stallion would have to gallop in front of the group to ensure that mares did not straggle from the rest of the group in higher intensity movements.

The vigour or intensity of this behavior is assumed to correspond to how low the head is dropped and the general speed and gait adopted by the stallion. Not only that but how far ears are pinned in a backward position may also be indicative of intensity.

Additionally stallions may move the head from side to side in a snake-like fashion usually referred to as snaking movement, or head tossing (Berger, 1986). So, if a stallion approached with the herding posture at a walk, it was most common that the targeted conspecific/s would respond in a similar pace.

Stallions usually approached from the rear pushing the individuals forward, but they also approach from slightly to one side in order to direct movement.

Feist & McCullough (1976) observed this behavior in their study of the Pryor Mountain  feral horses of Montana. From a total of 139 instances wherein stallions were recorded to perfom this behavior, they noted that 42% (n=55) of these corresponded to stallions herding or driving their band away from other bands or stallions, in 30% (n=39) stallions where guiding the direction of movement of their bands while on the move, 12% (n=15) of the time stallions singled out a mare for courting, in 12% (n=15) stallions drove  non-band members away from theirs, and in the remaining 4% (n=6) stallions herded-in new members.

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If you are a photographer or happen to have images related to this topic, and wish to share them, please do contact us. We could surely use them, and would appreciate it greatly!

This is a work in progress under our ongoing Equus Ethogram Project, further information and suggestions are welcome and will contribute to further updates.

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Reference list

Berger, J. (1986) Wild Horses of the Great Basin The University of Chicago Press, Chicago, IL

Feist, J.D. and D.R. McCullough (1975) Reproduction in feral horses. J. Reprod. Fert., Suppl. 23:13–18.

Keiper, R. (1985) The Assateague Ponies. Tidewater Press, Cambridge, MD.

McDonnell, S.M. (2003). A practical field guide to horse behavior: The Equine Ethogram. Lanham,US.: The Blood-Horse, Inc.

Rees, L. (1984). The Horse’s Mind. London: Stanley Paul.

Tyler, S. .J (1972) The behaviour and social organization of the New Forest ponies. Anim. Behaviour Monographs 5 (2): 85-196.

 

Peter Pan Horsemanship

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Where does one begin to describe some of the interesting “just so stories” used to describe human-horse interactions? From horses trying to play herd games with humans, trying to move our feet, or win over some spirited ritual over a resource such as water or food.

Before going any further, for those not familiar with the great writer Rudyard Kipling and his equally famous “Just So Stories,” these are a series of stories in which Kipling gives imaginative explanations related to why something is the way it is, especially in regards to animals.

Most of what I would call “just so stories” in horsemanship are based in some way or other on horses allegedly trying to establish some sort of rank over the humans that interact with them, although not limited to these confabulations.

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That is where Peter Pan horsemanship comes into play. I have witnessed, heard and watched several excellent horsemen demonstrating their talent with horses, although I may not always agree with their ways, they sure do know how to move horses. Having said this, my neurons go haywire when they try to explain why horses behave the way they do, or why the horsemen do what they do, or advise others to do the same.

Relax, Peter Pan Horsemanship is not another method, it is a call to attention to some horsemen who unknowingly use “just so” stories to explain their craftiness with horses, an appeal to critical thinking if you will.

Most of these “just so stories” are based on naturalistic fallacies: This is the way that it happens in nature and therefore it must be right.

Why would any good horseman need to justify his experience in this way is beyond me. Plus, most of these methods are not actually based on studies of free-living or feral horses, they are “just so” stories, invented by people with vivid imaginations.

Peter Pan type horsemanship is responsible for encouraging people to attain “Alpha,” “Dominant,” or “Lead Mare” status in a supposed herd of two. However, as most may already know these social outcomes are in fact contextual, if at all existent.

In regards to Alphas in wolf packs he studied, L. David Mech had this to say:

“Such a designation emphasizes not the animal’s dominant status, which is trivial information, but its role as pack progenitor, which is critical information.” Read the full article Alpha Status, Dominance, and Division of Labor in Wolf Packs or alternately you can watch this video:

Roger Abrantes clarifies and defines Dominant behavior as follows:

“Dominant behavior is situational, individual and resource related. One individual displaying dominant behavior in one specific situation does not necessarily show it on another occasion toward another individual, or toward the same individual in another situation.” Read the full article Dominance—Making Sense of the Nonsense

The idea of the lead mare has not been found to hold true in many populations studied. You can read the most recent paper Movement initiation in groups of feral horses by Konstanze Krueger et al. (2014).

Imagine a horseman who works brilliantly with horses both on the ground and ridden, wooing the crowd with flashy skills, but the minute he opens his mouth, he blurts out gospel and fairy tales in what I call the Peter Pan Effect. He may start moving the horse aptly around an arena, and everything looks good, kicking up very little dust as Ray Hunt would say.

Because the work is well done and adapted to the individual horse, anything the horseman says may be taken literally by all that watch and listen. Although I must say that few methods are in reality adapted for individual horses, but instead are vast generalizations.

So if the horse is moved around with grace and training progresses, one explains what one believes to be the reasons behind one’s ability.

After all, we can only rely on what we know to explain what we observe, and knowledge in some cases at least regarding behavior is pretty limited in the horse world.

One could say: I am the Alpha or dominant individual, the lead mare, or alternately: the horse understands because I am moving his feet and this is what other horses naturally do. Replace these musings with I do this to horses because Peter Pan told me too, or because Tinker Bell or even Captain Hook, appeared to me in a dream and told me this was the way, and little would really change in the interaction.

As far as we know, and I stand to be corrected, horses are not intent to move other horse’s feet. No seriously….how can we ever know that the horse actually attempts to move feet; it could be a flea or tick on the back of the other horse that is being targeted, or an ear for that matter?

What bogus subjective rubbish!!!

It really would not matter much if it did not cloud our understanding of equine behavior, or undermine the many serious studies undertaken on horse behavior and learning theory that are readily available for those that care to consider looking into things with more depth.

So, for the sake of understanding horses for what they really are: what natural selection including man’s hand in artificial selection has favored them to be, please consider that there are simpler explanations at hand supported in some way or other by a scientific view. One should be careful not to fall prey to the many forms of Peter Pan Horsemanship that abound.

Huddling in horses

In a previous post, the concept of affiliative behavior was discussed and defined, and the phenomenon of affiliation in horses introduced, as a distinct class of behaviors’ (Read: Affiliative behavior in Equus caballus), much like that afforded to agonistic behavior.

Affiliative behavior was defined as “(…) the activities between two or more (dyadic, triadic or polyadic) individuals within a social group with the function of developing, maintaining or enhancing social bonds.” {Equus Ethogram Project}

In particular we will focus on huddling behavior and describe some of the intricacies of this cooperative behavior in several species with emphasis on horses, Equus caballus (or Equus ferus caballus, for those considering this taxonomic line of thought).

Many organisms’ bunch, crowd, or stand closely together with the function of keeping warm, conserving energy, strengthening social bonds, avoiding insects or as an anti-predatory response amongst others.

This “(…) active and close aggregation of animals” (Gilbert, 2010) is usually referred to as a huddle. Horses huddle too, but what for?

Most often, huddles are linked to thermoregulatory processes, and this social thermoregulation, or “(…) the ability of some species to use sociality or grouping to regulate their body temperature” (Gilbert, 2010), is a common energy saving strategy for many endothermic species (Canals, 1998; Alberts, 1978).

By bunching together, individuals reduce the body surface area exposed to inclement weather, consequently reducing energy spent in regaining a conservative equilibrium (Humphreys, 1933), or homeostasis.

For example:

Pups of Norway rats, Rattus norvegicus, were found to lessen individual body heat loss and oxygen consumption when huddled. (Alberts, 1978)

Mottled gray pulmonate slugs, Limax pseudoflavus, “(…) form closely packed huddles within their day-time resting sites” (Cook, 1981), resulting in water conservation.

Male Emperor penguins, Aptenodytes forsteri, huddle tightly to battle polar winds and freezing temperatures. Emperors’ huddle in groups of up to 6000 individuals achieving an air temperature within the huddle of up to 35°C, while air temperatures in the perimeter are well below 0°C. (Gilbert, 2007)

Recent studies by Zitterbart (2011) highlight the continuous self-regulatory and coordinated movements of huddled male Emperor penguins which allowed those in the periphery temporal access to warmer positions within the huddle, while the whole time balancing their mates egg on their feet.

See video:

In terms of horses huddling as a means of social thermoregulation, there really is very little work done. During cold weather horses have been observed to huddle or crowd together, on windy or rainy days; horses typically stand close to one another with “backs to weather” or “backs to natural windbreak”, as described by McDonnell (2003):

Backs to weather – Typically observed during windy or rainy days, Two or more horses stand closely together with their “(…) hindquarters into the wind.” (from the Equid Ethogram p. 79)

Backs to natural windbreak – Two or more horses stand closely together with their “(…) hindquarters protected from the wind by vegetation or other feature of the environment.” (from the Equid Ethogram p. 78)

McDonnell (2003), suggests that the backs to weather behavior reduces the body surface area exposed to inclement weather, thus minimizing heat loss; in short it serves a thermoregulatory function.

With thermoregulation in mind and considering that standing close together exposes each individual’s surface area to the others’, these confronting surfaces are likely to maintain a constant temperature, thus non-evaporative heat loss decreases (Morgan, 1996).

Social thermoregulation aside, huddling is suggested to perform a social function as well (Alberts & Brunjes, 1978; Dunbar, 1991; Spruit, 1992; Takahashi, 1997). Many of the species studied, present a significant correlation between preferred partners, based on the frequency, distance, and duration individuals are proximate to one another.

In a study on the Japanese macaque (Macaca fuscata) troop on Kinkazan Island, Hiroyuki Takahashi of Kyoto University found that huddling was more frequent among kin and affiliative dyads, than it was among non affiliative dyads (Takahashi, 1997). Furthermore, Takahashi (1997) suggested that huddling strengthens social affiliations between non-related individuals.

In horses, the social bonds between unrelated mares, friendships, contribute to reproductive success as suggested by Cameron et al (2009) in a study on the Kaimanawa feral horses of New Zealand.

Horses have preferred partners within their band or herd with whom they associate more often with than other members of the group. Claudia Feh (1987), found that in the Camargue horses, horses had up to two, rarely three, preferred partners. These affiliative interactions are characterized by individuals sharing “personal space” (Dierendonck & Goodwin, 1992), and synchronizing activities.

Despite huddles not being extensively studied in horses, it is frequently mentioned in equid related literature, especially regards to group rest (Tyler, 1972; McDonnell, 2003; Ransom & Cade, 2009), or social grooming such as in mutual insect control. (McDonnell, 2003; Ransom & Cade, 2009)

Group rest in horses is a synchronized activity wherein most, if not all, members of the band or herd rest at the same time, typically in close proximity of one another. (Tyler, 1972) Furthermore, Tyler (1972) suggested that group rest is socially facilitated: the behavior of one or more individuals’ trigger or initiate similar behavior in other members of the group, in other words; the behavior of one individual is socially contagious. (Thorpe, 1963)

Before going any further, let’s differentiate two types of huddles, namely; tight huddles and loose ones (Behnke, 2012). Tight huddles are those in which the majority of group members are in physical contact with one another, or separated by < 50 cms, leaving no gaps between individuals (Behnke, 2012). In contrast, loose huddles are those in which the majority of group members are in close proximity; from > 50 cms to < 150 cms, but not in physical contact with one another. Both between individual distances are currently in use in the ongoing Equus Ethogram Project.

Feist & McCullough (1976) observed horses typically resting in tight groups, or alternately, in groups of one or two pairs. (Feist & McCullough, 1976) Whether horses are grouped tightly or loosely may seem trivial, but for the sake of alienating the functional characteristics of different huddles, and their forms, the distance between individuals are of prime importance.

In tightly huddled horses, insect control is facilitated between group members. (Ransom & Cade, 2009) Several studies suggest that animals tend to group together when biting fly density or harassment is high (Bergerund, 1974; Schmidtmann and Valla, 1982; Rutberg, 1987; Rubenstein and Hohmann, 1989).

In the warmer months, which tend to correlate with an increase in insect harassment, two or more horses stand close together, typically tail to shoulder to the nearest neighbor. This is usually referred to as antiparallel standing. In this position, individuals take advantage of one’s proximity to another to keep pesky biting insects at bay. Typically, horses have flies swished from their faces by the tail of a neighbor, but this can also be achieved by rubbing or bumping with those close by.

Social grooming, or allogrooming (McFarland, 1987), is characterized by one individual grooming another. In this sense, it is plausible to consider differentiating uni-directional grooming from mutual grooming.  As the name implies, uni-directional grooming involves one individual grooming another without being groomed in return (at that moment), whilst mutual grooming involves two or more individuals grooming each other simultaneously. (McDonnell, 2003).

The function of allogrooming is twofold, as it not only serves to relieve horses of discomfort, such like that caused by itchy skin or biting insects, but it lowers the heart rate and cortisol levels of the individuals when directed at certain locations. (Feh & Mazieres, 1993; Haverbeke et al., 2002; Dierendonck & Goodwin, 1992).

“In mammals, grooming behavior appears not only to remove ectoparasites, but to play a role in cementing social relationships” (Dugatkin, 1997)

To initiate a mutual grooming bout, one or both horses approached the other head on (Feist & McCullough, 1976), “(…) with its ears forward and its mouth occasionally open with the lower teeth slightly exposed”. (Tyler, 1972)

A typical bout consists of two standing horses facing each other; nibbling at the neck, mane, forelegs and withers of their partners (Tyler, 1972). Alternately they stand antiparallel, with head to shoulder for the mutual grooming session.

Feist & McCullough (1976) noted that mutual grooming only occurred between members of the same group and in all possible combinations between group members.

Unlike mutual grooming described in the competition-reconciliation model, where the number of times groomed by another is relative to status, in horses this seems not to be the case as suggested by the random and multivariate grooming sessions afforded by feral horses.

Mutual grooming will be discussed further in a following section.

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Reference list

Alberts, J.R. (1978). Huddling by rat pups: multisensory control of contact behaviour. Journal of Comparative and Physiological Psychology 92, 220–230.

Alberts, J. and Brunjes, P.C.  (1978) Ontogeny of Thermal and Olfactory Determinants of Huddling in the Rat. Journal of Comparative and Physiological Psychology; Vol. 92, No.5, pp. 897-906

Alberts, J.R. (2007). Huddling by rat pups: ontogeny of individual and group behaviour. Developmental Psychobiology 49, 22–32.

Behnke, T. (2012) To Huddle or Not to Huddle: That is the Question . A Brief Study of the Basis for Huddling Behavior in Eulemur rubriventer. In dependent Study Project (ISP) Collection. Paper 1470

Berger, J. (1986). Wild horses of the great basin: social competition and population size. University of Chicago Press, Chicago.

Brunjes, P.C. and Alberts, J. (1979) Olfactory Stimulation Induces Filial Preferences for Huddling in Rat Pups. Journal of Comparative and Physiological Psychology, Vol. 93: 3: pp. 548-555

Canals, M., et al. (1997) Geometrical aspects of the energetic effectiveness of huddling in small mammals. Acta Theriologica 42 (3): 321-328

Contreras L. C. (1984) Bioenergetics of huddling: test of a psycho-physiological hypothesis. Journal of Mammalogy 65: 256-262

Crowell-Davis SL  (1994)  Daytime rest behavior of the Welsh pony (Equus caballus) mare and foal.  Appl Anim Behav Sci 40: 197-210.

Dierendonck, M. and Goodwin, D. (????) Social contact in horses: implications for human-horse interactions

Dugatkin, L.A. (1997) Cooperation Among Animals: An Evolutionary Perspective. Oxford University Press. Oxford, U.K.

Dunbar, R.I.M. (1991) Functional significance of social grooming in primates. Folia Primatol 57: 121-131.

Feh C (1987) Etude du développement des relations sociales chez des étalons de race      Camargue et de leur contribution à l’organisation sociale du groupe. Thèse d’université, University of Aix-Marseille, France.

Feh C, de Mazières J (1993) Grooming at a preferred site reduces heart rate in horses. Anim Behav 46: 1191-1194.

Feist, J.D. & McCullough, D.R. (1976) Behavior Patterns and Communication in Feral Horses. Z. Tierpsychol, 41, 337-371

Gilbert, C.G., Robertson, Y., Le Maho, Y., Naito, A. and Ancel, A. (2006) Huddling behavior in emperor penguins: dynamics of huddling. Physiology & Behavior , 88(4-5), 479-488

Gilbert, C., McCafferty, D., Le Maho, I., Martrette, J. M., Giroud, S., Blanc, S. and Ancel, A. (2010) One for all and all for one: the energetic benefits of huddling in endotherms. Biol. Rev. 85: 545–569

Haverbeke, N.S. et al. (2002). Heart rate reduction by grooming in horses (Equus caballus). Dorothy Russell Havemeyer Foundation Workshop. Horse Behaviour and Welfare. Holar. Iceland http://www2.vet.upenn.edu/labs/equinebehavior/hvnwkshp/hv02/odberg.htm.

Haig, D. (2008) Huddling: brown fat, genomic imprinting and the warm inner glow.  Current Biology 18(4): R172-R174.

“Huddle.” Merriam-Webster.com. Accessed January 18, 2014. http://www.merriam-webster.com/dictionary/huddle.

Jefimow, M.; Glabska, M. and Wojciechowski, M. (2011) Social thermoregulation and torpor in the Siberian hamster. The Journal of Experimental Biology 214, 1100-1108

Linklater, W.L. (2000). Adaptive explanation in socio-ecology: lessons from the equidae.Biological Reviews of the Cambridge Philosophical Society, 75(1), 1-20.

Linklater, W.L. et al. (2000). Social and spatial structure and range use by Kaimanawa wild horses (Equus Caballus, Equidae). New Zealand Journal of Ecology, 24(2), 139-152.

McDonnell, S.M. (2003) The Equid Ethogram: A Practical Field Guide to Horse Behavior . Eclipse Press, Lexington, Kentucky

Ransom, J.I. and Cade, B.S. (2009) Quantifying equid behavior— A research ethogram for free-roaming feral horses:U.S. Geological Survey Techniques and Methods 2-A9

Rees, L. (1984). The Horse’s Mind. London: Stanley Paul.

Rubenstein, D.I. & Hohmann, M.E. (1989) Parasites and Social Behavior of Island Feral Horses. Oikos 55: 312-320.

Sealander J. A. (1952) The relationship of nest protection and huddling to survival in Peromyscus at low temperature. Ecology 33: 63-71

Spruijt, B.M., Van Hoof, J.A.R.A.M., Gispen, W.H. (1992) Ethology and neurobiology of grooming behavior. Physiol Rev 72(3), 825-852.

Takahashi, H. (1991) Huddling Relationships in Night Sleeping Groups Among Wild Japanese Macaques in Kinkazan Island During Winter. Primates, 38(1): 57-68

Tyler, S.J. (1972) The behaviour and social organization of the new Forest ponies, Animal Behaviour Monographs, 5: 85-196

Zitterbart DP, Wienecke B, Butler JP, Fabry B (2011) Coordinated Movements Prevent Jamming in an Emperor Penguin Huddle. PLoS ONE 6(6): e20260

Lichen licking in feral Pottokas

Our recent field study workshop [FSW] in collaboration with Lucy Rees, and the Piornal Pottoka Project of Extremadura, has just concluded. Many behaviors have been added to our ongoing Ethogram project, amongst which I am thrilled to report on lichen licking behavior.

Horses are usually considered to be grazers and to a lesser degree browsers and both these foraging forms have been documented extensively. In fact grazing can be understood as the ingestion of grassy or grass-like plants while browsing is the ingestion of woodier plants (McDonnell, 2003). In the former horses usually walk while grazing, placing one foot forward at a time and eating around it in at an arc type movement. Browsing has been observed to be a more static form of foraging were the horse may reach up, down or sideways to eat foliage of woodier plants, shrubs and trees while standing almost stationary.

Grazing

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Browsing

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The image below shows members of a mixed bachelor band together with a stray (dispersed) mare and foal from an adjacent band with overlapping home ranges that gathered around a particular rock. The horses gathered facing the rock with heads lowered and at first sight, from a distance of approximately 100 meters, it seemed that the horses were scraping and eating stone.

DSC_0053 ©

As we approached the group for a closer look it became evident that it was not the actual rocks that attracted them but the lichens and mosses growing upon these. The horses were observed to lick the lichens on the rock and in some cases flakes of lichen were observed to be licked-up and consumed.

A lichen is neither plant nor fungi but a combination of these or more organisms (see below), and the form employed by horses in the acquisition and ingestion of lichen is neither that typical of grazing or that of browsing. In both forms discussed, plants are gathered into the mouth with lips curled and tongue, vegetation is then ripped in clumps by way of a jerking movement of the head while simultaneously chewing.

With lichen, the horses observed were typically stationary such in browsing, while licking the flattened, crusty and granular crustose lichens that had fastened onto large rocks. Occasionally lichen flakes were licked-up, once moistened, or were alternately scraped off with the teeth of the lower jaw. Horses were also observed to peel away lichen flakes with both prehensile lips and apparently swallow.

The licking of lichen and its ingestion is fairly similar to a number of behaviors categorized in Sue McDonnell’s: Equid Ethogram (2003). In fact by combining the lick behavior categorized in the ethogram in which horses explore the surroundings with their tongues, and that described under pica behavior as the ingestion of soil by drawing it into the mouth by way of tongue and lips, and swallowing, would give a pretty close approximation of the activity patterns involved in licking licken.

Lichen Licking can thus be considered as a combination of licking and pica, an ingestion by way of moistening of the crustose lichen with the tongue, then drawing the lichen flakes into the mouth by way of tongue and lips and ultimately swallowing. The behavior was observed in short bouts lasting a mean of 2-3 minutes and much longer period that lasted up to 32 minutes. It should be noted that all 5 members of the mixed bachelor band along with a mare and foal from an adjacent band licked lichens.

In particular the lengthiest lichen licking bout was by the mare “Gastain” and her 4 month foal (not yet named) who clocked 32 minutes each on a single large rock. This lengthy bout was preceded and followed of shorter 2-3 minute bouts on other rocks in the area.

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“Gastain” lichen licking with “Serrana” close-by

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Crustose lichen after being licked by the horses under observation
Crustose lichen after being licked by the horses under observation

….and a bit on Lichens

Lichens come in many shapes and sizes and are found in the majority of ecosystems from ice free polar-regions through to tropical rainforests. They have been known to provide a forage source to many small mammals and artiodactyl ungulates such as Caribou, Reindeer and mountain sheep.

It is common knowledge that Reindeer and Caribou rely on lichens for their diets, hence the misnomers referred to Reindeer or Caribou Moss, which are in fact fruticose lichens normally of the family Cladoniaceae

Lichens are not plants, algae or fungi per se. Instead lichens are an association between 2 or more organisms that form a composite symbiotic relationship, which at times may be mutually beneficial to fungi, algae and cyanobacteria alike, or on the other hand it may be parasitic in which only one of the actors, usually the fungi, derive benefits at the cost of the others.

The fungal partner in the association is referred to as a mycobiont, while the non-fungal partner whether protista or monera is referred to as the photobiont, as these undergo photosynthesis which allows for the production of carbohydrates and thus the provision of nutrients for microbionts to harvest.

With over 20,000 species of lichen known identification is not always an easy task, but they can generally be classified into 4 distinct groups as follows:

1.  Fruticose – bushy structure which appear erect or pendulous and are markedly three-dimensional.

2.Crustose – Typically observed as flat crusts on or below rocks or under the bark of a tree. Crustosian lichens are markedly two dimensional and firmly attached to rocks, trees and other substrates by their entire lower surfaces, hiding in this way its entire undersurface.

lichen fly
Close-up of the area preferred by the mare “Gastain” in her 32 minute lichen licking bout. The fly conveniently posed for scaling.

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lichen closeup
Close-up of the area preferred by the mare “Gastain” in her 2 minute lichen licking bout.

3.Foliose – flat, leaf-like structure halfway between crustose and fruticose lichens.

4.Squamulose – tiny, scale-like squamules form these lichen which are sometimes classified within the category of crustose or foliose lichens.

Lichens come in many colours which clearly imply a richness of chemical compounds, the richness of which can only be understood through detailed analysis. These chemical compounds can be broken down into 2 further classes; primary metabolites that include amino acids, proteins, vitamins and polysaccharides which are normally soluble in water, and secondary metabolites which may include some antibiotics and chemical defenses against herbivorous vertebrates feeding on them.

Samples have been taken for laboratory analysis and identification and results will be posted accordingly in due course.

Some interesting articles and links on lichen:

The surprisingly toxic world of lichens

The British Lichen Society

Introduction to Lichens an alliance between kingdoms

The horses were observed to be licking away at flattened, crusty and granular like crustose lichens. Enjoy the gallery!

Quick-link to some of our posts:

Koniks at Oostvaardersplassen

The Oostvaardersplassen is a unique nature reserve with a variety of habitats which include marshes as well as wet and dry open grasslands that extend over an area of about 5,600 hectares. The reserve is overseen by Staatsbosbeheer which is the Dutch State Forestry Service.

Curiously enough, most of this 56 square kilometer reserve is below sea level with a mean altitude of -4 meters;  the reserve having been set on reclaimed land that was gained back from lake Ijssel in 1968. The land was initially destined for the heavy industries sector, but the area was left untouched for many years, and nature claimed it back. The reserve can basically be devided into a wet and a dry area of 3600 and 2000 hectares respectively.

Before the establishment of the reserve, the dry area was apparently a nursery for willow trees, and it is said that in the first year a vast proportion of willow seedlings could be found per square metre. This led to concern that a dense woodland would develop in the drier area, significantly reducing the value of the habitat for water birds.  Greylag Geese, Anser anser, soon arrived in Oostvaardersplassen soon after the area was drained in the early 1970s.

The arrival of the geese proved valuable at balancing off the years of abandon. Their numbers and foraging habits maintained the openness of the reclaimed land. Without the grazing geese, this fertile area would be overgrown and rapidly growing species such as willows and reeds would prosper, decreasing the biodiversity.

“(…) Non- breeding Greylag Geese from all over Europe chose the site to moult during May and June. During moulting they lose all their primaries simultaneously, which renders them incapable of flying for 4 to 6 weeks. Obviously, they are very vulnerable during this time and they therefore seek out inaccessible areas to retreat to, like the marshy area of the Oostvaardersplassen. Up to 60,000 (non-breeding) Greylag Geese retreat to the marshland to moult (Van Eerden et al., 1997).” (from Frans Vera)

To assist the grazing geese and further maintain the openess of the habitat, Heck cattle, red deer and konik horses,  were released into the area in 1983, 1984 and 1992, respectively ( http://www.staatsbosbeheer.nl), and are allowed to live and behave as their wild ancestors, with no supplemenetal feeding and living out all year round.

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“In 1983, 32 Heck cattle were introduced at the Oostvaardersplassen. In 1985, 20 konik horses followed as did 57 red deer over the course of 1992 and 1993. The animals have since been counted once every three years, among other things, using aerial surveys. The herds have developed naturally and the largest number of animals so far was a total of almost 4,000 animals in 2008.” ( http://www.staatsbosbeheer.nl)

Please respect copyright! ©Victor Ros and Equilibre Gaia 2012
Please respect copyright!
©Victor Ros and Equilibre Gaia 2012

Thanks to Dr. Machteld van Dierendonck, without whom this experience would not have been possible.

We  were a total of 5 (Machteld, Eva, Sef, Thessa and myself) in the counting team, but only four of us attended the counts on any one day. Following the Protocol for counting Koniks 2012 previously prepared by Machteld, we set out for the Oostvaardenplassen to count this primitive looking horse.

Upon our arrival at the Staatsbosbeheer park officeswe were briefed as to the current situation at the park, provided with coffee, a snack lunch, and a 4×4. The park rangers had informed us that the herds have merged to form 1 or 2 massive herds. We were also infomed that Deer and Heck cattle counts had been underway and still in progress. We were in for a long couple of days of endless counting, as we intened to take at least three counts of each group, daily.

We all boarded the 4×4, armed with binoculars, clipboards, mechanical counters, telescopes and all one could possibly need for the job, oh and lots of coffee and tea.

Once inside the OVP, I realised the vastness of the habitat, which reminded me much of the Venezuelan savannah in rainy season. As we drove through the park we spotted a massive group of horses, well massive is not the right word, Humongous would be more apt, as there were well over 400 adults in the group, breathtaking really. Leaving this group behind we ventured to the extremes of the park to attmpt localizing all the different groups before starting the count.

konik on the move

Sef, who was sitting in the back seat on the right side, saw movement in the thickets at about 200 meters and confirmed that it was a large group of horses on the run in the direction we were coming from. Machteld, who was obviously familiar with the terrain proposed that we try and anticipate their direction and wait until they settle down.

The herd finally settled down, and was loafing while drifting directly in the direction of our vehicle. They seemed to pose for our counting, not at all disturbed by our presence or that of the vehicle. This group was counted at point by all four of us at least three times, and our means did not vary more than 1 individual. In the end we counted all groups, well there were only three, which made things easy in that aspect. However there was one large group of about 80 individuals, and two Humongous groups of 400+ adults each. Needless to say that counting the two different groups of 400+ adults was a laborious task. When the group finally settles, individuals lie down, or bands are so cohesed that one individual blends into another. The bigger groups were counted by way of transects and point several times each day, by each observer.

I am not providing the final counts, as these will be provided in due course once the final report has been submitted and data made public. However, I would like to share some images taken during coffee and lunch breaks:

Enjoy the slideshow!

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Feral horses

Horses (Equus caballus / Equus ferus caballus) are found living a wild way of life in many parts of the world with little human intervention, or none at all. There is little discussion between scientists as to the domestic origin of most of these free ranging horse populations, although some do defend theories of non-domestic origin.

For those that consider that all extant wild living populations of horses indeed descended from domestic horses, the term used to describe them is “Feral” and below some examples of its scientific usage:

“The majority of the apparently wild populations around the world are in fact feral. That is they are domestic animals which have returned to the wild” Kiley-Worthington (1987)

“Feral horses are those whose ancestors or who themselves were domestic stock, but have been free running for some time” McDonnell (1999)

“A number of other populations of free-ranging horses or ponies like these at Assateague are found throughout the world. Some live on Islands while others rom over inland regions. Some populations have been studies by scientists, others remain unstudied. All these populations consist of feral animals, animals that have been domesticated but have since returned to the wild. There are no groups that have never been domesticated, and thus there are no truly wild horses in existence.” Keiper (1985)

“Historically, romantic names such as Mustang and Cayuse in North America, Brumby in Australia, and Cimarron, Begual, or Monstreco in South America were applied to free ranging horses. Today’s horses regardless of nomenclature are feral animals whose ancestors were once domesticated.” Berger (1986)

The word feral has its origins in the Latin fera, or wild animal, or ferus which is simply translated as wild. Funnily enough, fairly recent (2003) adjustments to taxonomical nomenclature of horses have made space for the extinct wild ancestor of Equus caballus, the domestic horse. These previously unclassified ancestors were named Equus ferus and proponents of this line of thinking suggest that the nomenclature of domestic horses should thus be: Equus ferus caballus.

Furthermore modern dictionaries like “American Heritage® Dictionary of the English Language, Fourth Edition 2000”, propose in most cases two distinct definitions for feral, as follows:  

1) Existing in a wild or untamed state

2) Having returned to an untamed state from domestication.

Recently however, some scientists propose reconsidering the use of the term “feral” for designating free ranging horses on at least two grounds. The first is the theory or belief of native indigenous non-domestic descent, while the second is a plea against its usage based on likely negative consequences as in this quote from Kirkpatrick & Fazio:

“Customarily, such wild horses that survive today are designated “feral” and regarded as intrusive, exotic animals, unlike the native horses that died out at the end of the Pleistocene. But as E. caballus, they are not so alien after all. The fact that horses were domesticated before they were reintroduced matters little from a biological viewpoint. Indeed, domestication altered them little, as we can see by how quickly horses revert to ancient behavioral patterns in the wild.” (Kirkpatrick & Fazio 2008)

The above statement may be true, false or partly both, but that does not change the fact that Kirkpatrick & Fazio are aware of the domestic ancestry of horses. They however claim that domestication, which truly is a blink of the eye in as much as evolutionary timescales are concerned, has altered horses little. The topic of little genetic alteration through domestication will surely be a topic for others to refute if they wish to, but for the purpose of this article let us concentrate on the issue of having descended from domestic stock as the reason behind the term feral.

Ross McPhee, Curator of Vertebrate Zoology at the American Museum of Natural History, recently defended the “nativeness” of Equus caballus to the North American continent with an apt and eloquent argument. In a nutshell: the bulk of horse evolution occurred in North America up to a species very similar to Equus caballus, and these crossed over to Eurasia and South America before going extinct in Northern America, later to be re-introduced by colonizers to the same continent from which they once came. (Read it here: MANAGED TO EXTINCTION? )

Once again, it seems there is no dispute that the extant wild horses of North America have indeed descended from domestic stock. Whether one should reconsider horse’s native, indigenous etc… or not, has no bearing on whether they are feral =>from domestic descent.

In basic terms, the following description from the American Museum of Natural History sums it up pretty well:

“The so-called “wild” horses that abound in Australia and North America are actually feral. A domestic animal becomes “feral” simply by fending for itself when left in the wild, without being helped or managed by humans in any way. If it finds others of its own species, reproduces, and the offspring also fend for themselves in the wild, the result is a feral population.” ( http://www.amnh.org )

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Some criticism on the matter of feral vs. wild

The matter of feral versus wild has inundated the social media. The main marketing strategy for this seems to be “you’re either with us or against us”, pushing people to think that those that utilize one term are “good and intelligent” while those that use the other are “misinformed, conspiring or misguided”.

BOLLOCKS!

It saddens me to think that people who share a passion for horses can be so self-centered and can’t see past the tips of their noses. Social media is an easy way to spread gospel and biased unsubstantiated claims about the work of others, and it’s apparently free. I do understand that much of the gospel is spewed forth for the best of intentions, but good intentions are biased by necessity. I refrain from posting examples of this carefree slander, so as not to fuel bad taste.

Controversy, what controversy? There really is none in the usage or definition of the term “feral”. Free ranging horses, wherever they may be in the world, are either descended from domestic horses, or they are not.

In my opinion, debates on topics like these only distract people from many other aspects more important to the preservation and conservation of free-ranging, feral, or wild horses such as further behavioral and ecological field studies that are likely to result in more viable and stable management schemes.

A plea for protection and conservation

Whether we label free ranging, wild or feral horses in one way or another, antiquated and biased population maintenance practices still abound.

In many parts of the world there are heated debates as to whether horses, the descendants of those that once carried man into the modern ages in more ways than one, should be left to roam freely or should be controlled strictly and considered an invasive pest.

The word we use to describe a population that is when once was not, or even, was and has not been for some time, will make no difference to our need, or greed for expansion. Many populations of free-ranging horses have been reported to cause havoc to local flora and fauna in their ranges. Some people may consider this unacceptable others just unavoidable given the circumstance.

Damn, that’s a very difficult question to answer in many respects. We have already interfered with most ecosystems in the world, either directly or indirectly. Our encroachment of greener pastures for whatever our interest, has pushed horses into marginal lands across the globe.

Now our encroachment is taking that away from the horses too!

In my opinion science is not likely to sort out our moral, ethical or political beliefs or battles, but it can give us the criteria to freely decide for ourselves.

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“The coming generations will have good reason to call us unfaithful stewards if when we are gone there are no longer little horses on the Exmoor hills.”  Mary Etherington (1947)

I would like to extend Mary Hetherington’s quote to include the majority of the free ranging feral horse populations in the world that are having a bumpy ride on earth because some species are considered worthy of protection while others are not.

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Further articles regarding the feral-wild-native-indigenous dichotomy:

Are the wild horses of the American west native?

The Surprising History of America’s Wild Horses

Feral-vs-wild-horses

The Aboriginal North American Horse

The genomic signature of dog domestication reveals adaptation to a starch-rich diet (full text paper)

Group specific behavior as a basis for equine culture

There is growing evidence for culture in animals other than man. As a matter of fact, those inclined to evolutionary thinking have little doubt that many roots of human culture are found in non-human animals.

“There is no denying the complexity of human culture. However, focusing on an anthropocentric definition of culture occludes evidence of culture in other species.” Greggor 2012

Culture is another hot topic often thought to be uniquely human. Definitions of culture are heatedly debated by scientists and philosophers and it seems that agreements between the parties are not progressing much. Not much point arguing with those that hesitate to contemplate that the differences between man and other animals are of degree rather than kind as put forth by Charles Darwin (1878).

Ths particular group of free ranging horses in the Galician mountains seek refuge in rock formations. Photo by; Victor Ros
Ths particular group of free ranging horses in the Galician mountains seek refuge in rock formations.

For the scope of this article, the definition we have chosen to use is after that of Frans de Waal, as follows:

“Culture simply means that knowledge and habits are acquired from others — often, but not always from the older generation — which explains why two groups of the same species may behave differently.”

Furthermore Frans de Waal makes an interesting comparison between Chickens and other flighted birds:

“The question of whether animals have culture is a bit like whether chickens can fly,” de Waal says. “Compared to an albatross or falcon, perhaps not. But chickens do have wings, they do flap them, and they do get up in the trees. Now imagine a world devoid of flying creatures except for the chicken. We would probably be mightily impressed, writing poems and songs about how we wished to be like them.”

Following the definition above, it should not be surprising to learn that culture was once considered a purely human affair, but in fact is not uniquely human at all. Many forms of group living organisms, from fish to mammals, have some form of culture of their own.

The typical textbook example of culture in non-human animals is the sweet potato washing by Snow Monkeys or Japanese Macaques (Macaca fuscata), first described by Kinji Imanishi in the 1950’s while studying the primates in the Koshima Islet of Japan. Imanishi who predicted that culture should be present in all socially living animals, observed a female he later named Imo, wash dirty sweet potatoes and wheat in water to remove sand. This behavior never before recorded was socially transmitted to members of her troupe as well as to their offspring. Interestingly, Imanishi studied feral horses too!

from: http://pppl.blog.lemonde.fr/category/apres-nous-le-deluge/

But it’s not just our closely related primates that have culture. Cetaceans, which include whales, dolphins and porpoises, have been found to possess forms of culture by way of dialects in whale song, different group strategies for hunting or foraging, or even dietary preferences.

Polly wants a cracker? Many of us will be familiar with the capacity parrots have of imitating sounds. Most species of Parrots exhibit complex social behaviors which are imitated by group members. Groups of Parrots are also known to have between group difference in song, foraging strategies and dietary preferences. Songs of many birds such as starlings, cowbirds and sparrows are learned from others.

Even Guppies (Poecilia reticulata) have been shown to show cultural transmission through mate choice, whereby females tend to copy other females in choosing their preferred mate. Lee Dugatkin, found that if one female likes a particular mate, then other females will take notice and “date copy”, which is to say that females will choose males that attract other females.

So, why not horses?

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The art of over-simplifying an over-simplification!

“Everything should be made as simple as possible, but not simpler.” Albert Einstein

Many times I have come across articles that stress the importance of showing the horse who is boss, because it is believed that there are three types of horses in a herd, the boss horse, the not boss horse, and all the rest in between. These horses in the herd apparently rank pretty linearly from the boss horses down to the not boss horses.

5looking

A statement like that above is definitely the Horse Social Behaviour 1.01 Course on the art of oversimplifying the patterns of relationships in group living horses, but nonetheless….

How we emphasize structure and compartmentalise the behaviour of equines in their natural habitat is a purely human affair and has no bearing on the lives of feral horses. However, in a domestic setting, preconceived structures and the terminology we use has grave implications in how we act, and this in turn may unconsciously, adversely affect the horses in our custody.

Of course there are more or less assertive horses, whether in a natural setting or in that of a domestic one, be it in an intra-species or interspecies relationship with humans. The patterns one may observe from these interactions, and more importantly the description of these patterns vary greatly, even to the point of contradiction in some cases.

Falling back always on the idea that boss horses have this need to enforce their Alpha status, incessantly reminding everyone, including their humans, who the “top dog” or dominant individual in that particular relationship is, is well, dare I say, quite anthropomorphic, warlike and status conscious.

As most interested in animal behaviour may already know, dominance is understood mainly as a competition for resources. Mates, food, and suchlike are resources, and as far as I know, we do not compete with the horses over them. So what is really going on?

Well, we will never really know, if we always fall back on the simplistic application of a continuum of dominance-submission relationships throughout the animal kingdom. This simplistic approach, in my opinion is scientific laziness, although it may be a good starting point for investigations, it tells us very little of the natural lives of animals, their motivations, their adaptations and suchlike.

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Further reading!

Snapping at “Alphas” and submission in horses

Humans tend to have a stereotypic understanding of how horses behave, which is likely caused by the incredible amount of cultural baggage accumulated through millennia of relating to them. When I speak of human stereotypies in respect horses, I refer to those unquestioned practices that are detrimental to their maintenance and handling.

Dis-respectful 

It is often we hear suggestions that a dog or horse has acted, or not acted, in a certain way due to a lack of respect toward a particular person. “Respect issues”, are frequently used to label unwanted perceived attitudes or behaviors in human-nonhuman animal interactions.

The social life of feral horses | Part 1

Understanding the social structure and organization of animals helps us better define a class of ecological relationships, including those of con-specifics living together.  Description of these relationships is complex and challenging, and analysis of  patterns of relationships between individuals of a population a laborious one, entailing extended periods of observation.

Horse behaviour: generalizations from observations of one population?

It would be safe to state that, although Equus caballus clearly have innate patterns of behaviour, the feral horses being studied today have many adaptive consequences imposed by occupying new niches in geographical locations for which they have not evolved.

Horses evolved to ultimately live in groups in large open spaces, like plains and savannahs, but have adapted fairly well to life in places so marginal as the desert of Namib, or the coasts of Assateague and Chiconteague. Clearly the behaviours observed from these feral horses have many points in common, thus the commonality of the species, but again surely their behaviour must also differ in consonance with the constraints inevitably imposed by their relatively new environments.

A clear example of this, is that many feral horses no longer suffer selective pressures from predatory animals like larger canines or felines. This lack of predation, even if only to the slightest degree, must necessarily affect group cohesion, but not only in horses as it must be so for many other prey species as well.

A comparative approach between feral horse populations is hence called for, if any macro-determination of the behaviour of Equus caballus is to be sought. This means not that the observations on feral horses up to date have been futile, but it does mean that to have a fuller picture of equine behaviour, one should consider a “broader spectrum”, one which would invariably include particular adaptations to particular environments.

This would entail the consideration of a range of behaviours similar or differing across the species depending on the selective pressures of their environments. The existence of scarce resources or that of over-abundance will surely vary their life strategies. It would surely be naive to consider that a well fed animal would behave (goes about his/her business) in the same manner as one that is hungry.