Post on 16-Dec-2015
Horse Behavior
Moira IlgERS 69713-April-2004
Outline Introduction and General
Background Social Status or Ranking Foal and Mare Behavior Stallion Behavior Grazing Behavior Conclusions and Possible
Implications
General Background Factors that influence dominance
relationships Body size Physical condition Age
• Older the more dominant Sex Previous agonistic encounters Group size Dominance hierarchy of parents
Background continued Band structure
Single adult male Adult females and their offspring Normally stable
• Changes are normally juvenile males and females Juvenile males may remain solitary for months
or years Juvenile females normally bands
A well defined hierarchy is present during grazing and will persist if they are provided with food
General Background Behaviors
Threatening Behavior
• Maybe widespread or may have a few favorites to pick on
• Is often one sided• If there is a
“winner”, they move up in rank
Behaviors
Grooming•Normally
groom with two or three individuals that are similar in rank and age
Behaviors continued Play
• Important for social development of young
• Most common within in peer groups
Submissive• Often a response to
threatening behavior
Social Status or Ranking Top ranking individual
Large number of threats • Distributed widely across the herd• Often don’t have “friends”
Stallion • Is often times the only breeding male
Mare• Often decreases aggressions as rank
becomes higher
Social Status or Ranking Friends
• Normally close in age and social status• Mares may bond more closely with those
that are related to them• It is important account for “friendships”
when assessing the distribution of threats
Social Status or Ranking Tend to be selective about who they
interact with Animals tend to spend the most time near
individuals that have the same rank or age or both
Top ranking animals are seldom seen alone or in a small group Elders are less social than the young
• Often have fewer interactions with younger subordinate mares
Social Status or Ranking May recognize individuals that they
have competed with Leading to fewer competitions in older
animals
Theories of the evolution of bonds Evolved between mares and stallion
in a band because of pressure from predators that hunted cooperatively
Protect mares against harassment from other stallions and reduce inter-mare aggression
Mares Acts of aggression
is most common with mares that do not have foals
The least amount of aggression is seen between mares that have foals Protection of foals
Mares Intermediate aggression is seen
between mares that have foals and those that do not
Young mares are much more aggressive than older mares when foals were less than a week old
Mares continued Older mares have fewer encounters
of aggression• Number of acts of aggression decrease as the
mare becomes older
Aggression frequencies increase in May (foaling season)
Frequencies of aggression increase significantly the closer the mare is to parturition
The Advantage of Being A Dominant Mare Receive less aggression Access to shade on hot sunny or rainy days to
rest Increased access to feed Supermare May suppress conception, induce abortions, or
harass or kill offspring of subordinate mares However, dominant mares may not live as long
They have increased amount of stress and a increased amount of cortisol
The Disadvantages of Being A Subordinate Mare Increased acts of aggression Denied access to shady areas Give birth to fewer or less fit foals Denied access to food
Decreased growth rate
Foals Foals will often
play with foals of their dam’s friends
Also like to associate with foals of the same gender
Foals In the case of fillies they most often will
have a similar rank to their dam• Dams may assist their foals in agonistic
encounters• Foal-mare association• Genetics
Stallion Behavior Some bands will have multiple
stallions The subordinate stallions are more
likely to help defend the band than the dominant stallion
However these stallions are forced to stay on the periphery of the group by the dominant stallion
Grazing Behavior The time spent grazing is dependent on the
intake of the grazer Daily intake is determined by
Time spent foraging• Varies from a few minutes to 13hrs and 25 min
Bite rate Bite size
Are selective when quantity and quality of forage is high When drops below a threshold level they
become less selective
Grazing Behavior Foraging time increases for mares in
the summer months Major feeding bouts after dawn and
before dusk Feed mainly during the day except
for summer months when there is a midday lull
Grazing Behavior Often forage from plant communities
that are continuous with patches of more desirable plants
May use spatial memory to find those plants that are the most desirable
Study by Edwards et al., 1996
Grazing Behavior Most large herbivores rest in the
areas that they graze Some herds have been shown to travel
over 1 kilometer to high ground, saltflats with low plant cover, or denuded vegetation
Yet when they arrive they show signs of extreme discomfort
Grazing Behavior So why travel all that distance?
Higher altitude cooler temps?• Unlikely, cooler temps are more likely to be
found in shady areas rather than bare ground
Fewer biting flies?• Probably, though the reasons are unclear• Most likely the flat, open areas are poor
habitat for biting flies
Grazing Behavior Is it really worth the effort?
They can lose up to 500cc of blood to biting flies a day
Biting flies are also the carriers of disease
• Anthrax• Lethal arbovirsues
Horses actually spend less energy in the comfort movements
Grazing Preferences Preferences
Prefer gentler slopes
Mesic grasslands Avoid
Steep slopes Drier grasslands Large tracks of
forests
Home Range Home range varies in size in relation to
the band size Home ranges overlap Groups can move seasonally Home range cores become larger during
winter months than in summer months Change elevations for foaling and mating
Methods Focal animal Focal groups
Problems In feral herds it is often times
difficult to identify individuals Identify distinctive individuals
• Markings• Colorations• Sex • Location
Counting by helicopter
Conclusion Horses are for the most part herd
animals and they move as a herd, but can be influenced by individualistic behaviors
There are reasons and patterns in their movements that can be predicted when their behavior is understood
Possible Implications Understanding behavior can allow
Better prediction of movements Understanding habitat choice Better herd management
QuestionsQuestions?