Post-Traumatic Stress Disorders in Wildlife
Many living beings show lasting changes in behavior and physiology following a traumatic experience
When hare populations increase, so do the numbers of predators.
Chronic stress from persecution
Hare populations are declining not only because predators or the hobby hunters take too many of them. The chronic stress of living among attackers causes mother hares to eat less and give birth to fewer young. The trauma of repeated persecution triggers lasting changes in brain chemistry similar to those observed in traumatised humans.
When scientists examined the droppings of live-caught hares, they found that the concentration of the stress hormone cortisol in mother hares fluctuated with predator density.
Lasting effects of trauma
Research shows that fear can alter the behavior and physiology of wildlife — from fish to elephants — over the long term. “Fear is a response that all animals use to avoid being killed by predators. It is of great benefit, because it keeps them alive. But it also comes at a price”, says Zanette.
Traumatised elephants
Some of the most dramatic effects of trauma in wildlife have been observed in African elephants. Today, many surviving elephants have witnessed their mothers and aunts being slaughtered before their eyes. A combination of early trauma and the absence of stable family units has caused orphaned elephants to run amok when they reach puberty.
«There are interesting parallels between humans and elephants. And in elephants that have experienced trauma, we observe a radical change in their development and behavior as they grow up», says Shannon.
The amygdala generates emotional memories. Humans or other animals with damaged amygdalas cannot remember the feeling of fear and are therefore unable to avoid danger. When neurogenesis is inhibited, the memory of the trauma becomes fixed in the mind.
Original article: Do Wild Animals Get PTSD?
