The reality is that the majority of zoos do not meaningfully contribute to conservation and that captivity hurts animals more than it helps them.
If you’ve ever been to see a mammal in captivity, you’ve likely seen them exhibit behaviors they wouldn’t engage in in the wild. Repetitive, often destructive behaviors like swimming in circles, grinding their teeth, and bobbing their heads are all symptoms of the effects of captivity on the animal’s brain. How does an animal’s brain change in captivity, and why is it detrimental them?
Living in an unstimulating, stressful environment has been shown to change the brains of animals from rabbits to humans. Such an environment has been linked to thinning of the cerebral cortex, reduced blood flow in the brain due to thinning capillaries, decreased length in dendritic branches, and less efficient synaptic connections, to name just a few examples. A thinner cerebral cortex, the part of the brain involved in voluntary movement and higher cognitive function, can result in poor decision making and worse memory. The change in dendritic branches and synapses means that captive animals process information less efficiently than those living in their natural habitats.
These brain changes do not happen in a microcosm. As an animal’s brain changes, so too do their behaviors. The primary change is that animals lose their some of their natural behaviors including food-finding, avoiding predators, and rearing young, and replace them with stereotypic, destructive behaviors brought on by chronic stress and boredom. These new behaviors are often self-destructive, like gnawing on bars and running headfirst into walls. They also show a marked difference between a captive animal and their wild relatives.