What does science tell us about depression in animals?
While many stakeholders in the commercial wildlife industry believe that animals respond to their environments based on instincts alone, science has demonstrated that animals can experience depression-like behaviours. This information is not new as an early (and highly unethical) study conducted in the late 1960s by Martin Seligman, an American psychologist, showed that dogs subjected to unavoidable electrical shocks gave up trying to escape their environments after repeated exposure. The phenomenon was termed ‘learned helplessness’ and became an important model for understanding depression in humans and animals.
What does ‘learned helplessness’ mean?
‘Learned helplessness’ occurs when an animal is repeatedly exposed to stressful situations outside of their control. Eventually these animals cease trying to escape their situations. Sadly, even when escape from long-term and repeated exposure to a stressful situation eventually stops, animals experiencing ‘learned helplessness’ may not even attempt to escape.
How does this relate to depression in animals?
Although Seligman’s study was extremely cruel and unethical, the concept of ‘learned helplessness’ became an important model for understanding the behavioural responses of people (and animals) to depression. It’s a powerful indication that chronic, uncontrollable stressful situations can lead to severe and lasting behavioural and neurochemical changes.
‘Learned helplessness’ can be seen in passive behaviour, a lack of motivation, and feelings of pessimism that things will never change for the better. In animals, scientists have found that those who display signs of ‘learned helplessness’ even have altered brain chemistry and behaviours similar to people experiencing depression.
Do animals in captivity experience depression and learned helplessness?
Science shows that wild animals kept in captivity can experience severe environmental deprivation, a lack of control, and long-term exposure to stress, all of which can lead to depression-like behaviours associated with ‘learned helplessness’, such as the following:
Animals showing signs of depression actually mirror what we see in humans experiencing depression, including neurochemical changes in serotonin (implicated in depression) and cortisol (the stress hormone), and neurological changes in brain function and structure.
What does depression look like in captive animals?
The general public often miss the signs of depression in animals kept in captivity, but the following are strong indicators that an animal is experiencing chronic stress and ‘learned helplessness’:
Animals kept in captivity show these behaviours because captive environments do not provide mental and physical stimulation, they feel isolated from members of their own species, and because they simply cannot escape their stressful environments.
What does this mean for the welfare of predators kept in captivity?
Captive facilities are by their very nature artificial environments that confine and restrict an animal’s ability to engage in natural behaviours. For predators, like lions and tigers, one of their most inherent behaviours – hunting – is impeded. They are robbed of their ability to roam their territories, hunt prey, and socialise with their own species in ways that are natural to them. Predators kept in captivity often exhibit signs that their environments are harming their well-being and quality of life. By supporting commercial captive facilities, we are failing to genuinely consider wild animals’ quality of life. Even if overt cruelty and neglect is not occuring in a commercial captive facility, captive predators quietly endure stressful and inadequate conditions from birth to death. One or two negative conditions may not feel harmful to the animal’s overall welfare state, but the cumulative impact over its entire life can turn into serious depression and severely affect a captive animal’s quality of life.
