Fear Disorders in Animals
This hub will discuss sources of fearfulness in various species, including both farmed and pet species. A proportional sense of fear is important for learning to avoid things that are dangerous. However an overly fearful temperament causes animals unnecessary suffering and can interfere with normal activities ad relationships.
Fearfulness (or timidity) is considered a personality trait and it has both learned and genetic elements. Domesticated animals usually show very low levels of fear and aggression, because a calm temperament is selected fro over generations of breeding. However certain lines are still predisposed to be fearful, especially if they have limited opportunities to learn and explore when they are young.
Fear in Domesticated Animals
One of the major functions of domestication in animals is to make them less reactive, both less aggressive and less fearful. In return the human caretaker tries to ensure the animals is not exposes to the kinds of danger that their wild counterparts need to learn to avoid. Domesticated animals are prepared to learn to trust humans and the features of human environments so long as they are handled gently during the early, sensitive period of their life.
Overly fearful domesticated animals can be a problem in a variety of settings. Excessive fearful reactions may lead a working animal being to nervous to carry out his or her duties, a pet animal to live in constant anxiety that is distressing to the owner, or a farm animal that will panic and become dangerous to people and other animals.
Older, less domesticate lines or hybrids with wild species are more inclined to revert to more fearful emotional behavior. And animals kept in isolation such as a puppy mill may have extreme difficulties adjusting to life in a normal home.
In cattle some breeds such as Brahman cattle are more reactive, and so more likely to respond fearfully to unfamiliar or startling stimuli. This is because the are more similar to the wild species that are the ancestors of our current domesticated species. These general breed level tendencies to be fearful can be increased by handling calves in a manner that it too dominating or too nervous instead of a clam and patient approach (Ellingson et al, 2014)..
Extreme fearfulness can be such a problem in poultry that the will panic and pile up in a reaction sometimes called 'hen hysteria', smothering some birds in the pile and breaking bones. There seem to be links between genes that make hens productive and those that predispose them to showing extreme fear reactions.
However this genetic predisposition is modified by many factors such as the fearfulness of hen even when the eggs are cross-fostered and can only be controlled by keeping these breeds in small groups and carefully controlled environments.
Porcine Stress Syndrome is the name of a metabolic disorder common in commercial breeds of pigs used to raised produce lean (aka low fat) pork. This disorder can be traced to a recessive gene. These pigs are particularly susceptible to stress and if frightened may collapse or even spontaneously die. The pork industry is breeding to remove this disorder from their herds and it is now relatively rare.
It has been shown that mink could be selectively bred to be less afraid of humans, and this boldness also extended to other novel situations. This was considered a good quality to select for in fur-farmed breeding programs as mink are easier to handle if they are calmer.
However just as improving meat quality made pigs more easily stressed, improving temperament (domestication) can easily lead to reduced for quality--as was found in an early Russian study of foxes. Tame foxes are available and Russia to the present day. They have behavior, coloring and a pelt more like a dog than a wild fox.
Temperament, including boldness/timidity is an important part of the suitability of dogs for work (such as police dogs). And genetic play a significant roles in determining a dog's temperament.
Several domestic breeds are known to have lines that are overly timid, including the Rough Collie (Arvelius et al, 2014) and the Sheltie. And some research lines of dogs have been specifically bred to be fearful to study the genetic basis of temperament.
Regardless of breeding, early socialization and consistent handling and training can avoid most domesticated animals demonstrating excessive fearfulness during normal day-to-day activities.
A variety of studies have a found a genetic component to fearfulness in diverse animal species including chimpanzees and quail.
Fear and anxiety have been shown to be strongly influenced by genetics in humans and other animals. Several kind of panic disorder have been shown to be transmitted within families as a autosomal dominant trait.
However environment also plays a strong role. So even if an animal is predisposed to be fearful both genetic and from an impoverished early environment, patient habituation can increase their tolerance for normal daily experiences.
Just remember that every domesticated animal need to have a place they feel safe, and a person they feel safe with. Only after you have established this trust ad security should you offer the timid animal opportunity to explore and investigate new stimuli.
- Arvelius, P., Asp, H. E., Fikse, W. F., Strandberg, E., & Nilsson, K. (2014, August). Good Possibilities to Select Against Fearfulness in Rough Collie. In 10th World Congress on Genetics Applied to Livestock Production. Asas.
- Ellingsen, Kristian, Grahame J. Coleman, Vonne Lund, and Cecilie M. Mejdell. "Using qualitative behaviour assessment to explore the link between stockperson behaviour and dairy calf behaviour." Applied Animal Behaviour Science 153 (2014): 10-17.
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