A while ago I wrote a post on the evolution of the horse. I am currently revising for my last exam which is on Monday morning and is on equine behaviour and welfare. Part of this module covers the evolution of equine behaviour so I decided to write a post on it.
Looking at the evolution of behaviour is interesting as the behaviours and level of intelligence that a horse shows must have evolved for specific reasons. They must have lead to an improved survival rate in the horse. Behaviour allows adaptation to the environment for protection, reproduction and body maintenance. An example of body maintenance behaviour is seeking shade when the weather is too hot or finding food and water.
When looking at fight or flight in the horse, flight is their primary mechanism of defence. In horses, their flight mechanism is very sensitive. They are built to be able to stand for long periods of time which is an advantage when being prepared to escape from predators. Horses will lay down but often only for a short period of time and when other standing horses are present.
Horses have evolved to be social animals. This has given them an advantage in a a number of areas including protection, maintenance and reproduction. There are often variations in herd structures depending on environmental pressures such as how much food and water is present. The natural herd structure is rarely replicated in the domestic situation. The dominance hierarchy may still be seen however. In the domestic situation the herd is often more unstable than in the wild. This is due to new horses coming on to a yard and other horses being sold and moving onto another yard. This results in the continual re-establishment of the hierarchy. Social isolation may also be seen in domestic situations, particularly in stallions who are often isolated which can lead to
Horses' social cognitive abilities have allowed them to succeed in a wide range of environments including those closely linked with humans.
Hamilton (1971) developed the selfish herd theory when looking at horses. It was thought that a horse may have had a mutation which increases it's reproductive strategy by taking cover between it's herd companions. This would make it less likely to be caught be predators. The novel behaviour would spread through the whole population as horses with this behaviour would be more successful at surviving and therefore reproducing.
The horse does have a strong tendency to gather in groups supporting Hamilton's selfish herd theory. However, other factors should be taken into account. The horses' ability to detect it's neighbours is an important factor in the dynamics of group formation. Not only the nearest neighbours but also the behaviour of distant neighbours gives useful information in case of predation (Viscido et al, 2002).
It has been found that when introducing a group of horses to a bucket of feed a hierarchy will be established. After a period of time dominant individuals showed tolerant type behaviour to other horses that were ranked below them in the hierarchy. Tolerated horses were found to have an increased food intake compared to non-tolerant individuals at an equal position in the hierarchy (Kolter, 1984).
Studies observing Prezwalski horses has show that a band’s
behaviour can be synchronised between 50-98% of the time. Communication between
the group helps this. Horses usually communicate without using their
voices as they are prey animals.
When looking at a band of horses the position they are standing within the group may affect their ear movements. Horses at the front of
a moving group tend to have their ears forward while the rest orientate their
ears backwards. This suggests that their ears are being used for surveillance.
When horses are frightened by or simply suspicious of a
stimulus, their alarm is often indicated by switching the direction of the ears
and by a tense mouth and dilated nostrils. Alarmed horses tend to withdraw from stimuli with jerky movements that contribute as a survival strategy
because they confuse the predator leading them unable to predict the horse's route of escape.
Primary forms of equine communication are vocalisation such
as whiney, neigh or squeal. Body postures are also important such as being agonistic or submissive. Ear
positions are another indicator as they have limited number of facial muscles but increased number of ocular
muscles. Ear position and movement often used to communicate, aggression, alertness and vigilance.
Before placing new horses in a group, it is preferable to
introduce horses to one another individually so that they have the opportunity
to form pair bonds. The first meeting of two strangers can be facilitated if
both are sufficiently hungry to be distracted by food sources placed a safe
Where possible the horse should be kept in social groups as
they respond poorly to being isolated. Horses without companions have been
found to spend 10% less time eating and are three times more active than horses
that could make auditory, visual and tactile contact with other horses. There
is evidence that mirrors may help.
This information has come from a variety of resources. I might write more of these posts on equine behaviour as part of my revision so watch out over the next few days. I am back home on Tuesday so will be back to normal blogging then and starting my dissertation.