Apure, Venezuela -vpr2011
Large social non-ruminant grazing herbivores
Horses are an herbivorous, grazing species that graze an average of 14-15 hours a day in the wild (Heird et al, 1998). Keiper (1985) found that horses on the Assateague spent 78% of daylight hours grazing. , Horses are not ruminants; they have a single stomach and the digestion of ingested roughage occurs in the cecum at the end of the large intestine (Heird et al, 1998). Cecal digestion, high level of food intake, and quick passage of food through the digestive system allows horses to have a diet high in fiber and low in protein (Waring, 2003). Although horses prefer grasses they are known to forage and derive nutrition from bark, tree, shrub buds, small woody stems, aquatic plants, fruits, roots and seeds. (McDonnell, 2003).
On Assateague Island along the Maryland-Virginia coast Keiper (1985), found that these horses graze during 54.6% of the night time hours. Tyler (1972) in her 3 year study of the New Forest ponies stated; ‘from the few observations that were made at night, it seemed that most of the hours of darkness in all seasons were spent feeding’. From these studies it seems that on the onset of darkness walking and drinking activity becomes greater, especially in the first hours of darkness (Keiper, 1985).
Drinking in feral horses is not as frequent as one would expect, many only drink once or twice a day and some have been noted to travel considerable distances to drink once every 2 days. Drinking activity is variable in time and frecuency and occurs both during day and night. (Pellegrini, 1971; Feist & McCullough, 1976) A direct corelation was observed between drinking frequency and ambient temperatures, with a clear increase in frequency occuring at temperatures above 30 C. (Crowell-Davis, 1985)
The horse has adopted early predator detection and flight as its primary defense mechanisms, thus rely on survival strategies centered on the formation of cohesive social bonds within stable bands (Mills and Nankervis, 1999). Horses are a prey species that live in herds for safety and protection (Heird et al, 1998). Horses have few predators. Wolves, lions, pumas, and bears have all been reported horse predators. Wolves are more commonly predators of foals than adult horses (Berger, 1986).
A herd is a localized population consisting normally of one or more bands (Waring 2003). Several kinds of groups can be seen in a herd. Besides the typical family or harem bands, consisting of at least one mare and her recent offspring plus an adult male, occasionally additional males accompany harem bands. Bachelor males often form small, less-stable assemblages of usually 4 or fewer members. Membership in bachelor groups commonly shifts throughout the year.
In the wild, membership of a group is such an important survival strategy that the social behaviour of the horse functions to minimize conflict within the group and so promotes its stability. Horses readily form social order and overt aggression in feral horse bands is relatively rare, compared with horses in the domestic environment (Houpt and Keiper 1982).
Individuals within a group of large herbivores in their natural habitat do not need to be in competition for much of the time. Consequently they may have developed a way of living together which concentrates, not so much on strategies for overcoming competition, but rather by displaying behaviours to foster group cohesion. (Kiley-Worthington, 2005)
Horses exhibit home range behavior, and its home range corresponds with the area occupied by other members of its band. (Waring, 2003). Abundance of food and water fluctuate seasonally in a horse’s home range.
Resources in a given home range are neither abundant nor evenly distributed; thus home ranges often overlap to share food, water, and shelter (Waring, 2003). However, the distribution and quality of resources within the home range affects the types of associations between band members.
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