Justification.
There are many ways to try to justify zoo enclosures. The animal gets food, has no visible predators, and has somewhere to sleep and live. However, when we apply these justifications- as if it were a human in the enclosure, it would be considered unjust. Humans would rather live free with the possible risk of predators, unknown food sources, or maybe an unknown place to sleep or live. Regardless, we have this desire for freedom. Shouldn’t they?

Speciesism: The Ethics of Enslaving.
There is nothing ethical about enslaving another being. Enslaving uses dominance, control, oppression, exploitation, and/or forced labor. Owning another being, as a piece of property is enslaving it. What was once living a natural and free life has been disturbed, separated, and transported across the globe to an enclosure for another species to profit from. For those who have an open mind and care about equality, I highly recommend checking out an award-winning 2013 documentary by Mark Devries called Speciesism The Movie.  As said by Huffington Post “Every now and then, a movie comes along that is capable of fundamentally changing the worldview of its audience. Speciesism: The Movie, a new documentary by Mark Devries, is that kind of film.”

Animal Evolution.
Animals who have been isolated from their natural environment are not able to evolve and participate in natural selection [2]. Something which was discovered years ago by Charles Darwin in 1859 [2]. Over the last several decades, the welfare of animals (while under the care of humans) has become a public growing concern [3]. Animal welfare in zoos became a recognized concern in 1950 during Heini Hediger’s publication of  Wild Animals in Captivity; where the study of zoo enclosure improvements and animal welfare was beginning [3]. Some of the studies during this time included: behavioral changes in animals as a response to captivity in un-stimulating environments and their reproductive system changes. If you have studied genetics, you would know the species relies on natural selection in order to obtain genes that are most beneficial to their current environment. Different genes will become more exclusive when the environment changes or the species migrate [4]. Species also rely on: mutation, gene migration, non-random mating, genetic drift, speciation, and adaptive radiation to alter the makeup of a good gene pool. Zoo animals experience selection to some extent, which can cause interference with the natural makeup and evolved gene pool that they have [3].

Animal Body Language & Mental health in Zoo Enclosures.
Zoochosis is the term used to describe the stereotypical behavior of animals in captivity. Stereotypic behavior is defined as a repetitive, invariant behavior pattern with no obvious goal or function. Stereotypic behavior is not seen in animals in the wild and is understood to be abnormal and is, therefore, a negative factor in conservation captive breeding [1]. For further information, you can watch The Zoochotic Report by the Born Free Foundation which was observed by Bill Travers in figure 1. You could also visit a zoo enclosure. Depending on zoo methods and the species, if an animal is unable to have control over their process, it will negatively affect its behavior. Animals require a form of control and choice in their environment to promote positive welfare [5]. The theory of contra freeloading, where an animal prefers to work for their food rather than receive it for free, is something we have learned about certain species over a duration of time (Forkman, & Lazarus, 1997; Osborne, 1977) [3].

figure 1. The Zoochotic Report by the Born Free Foundation

In Summary…

Common displays of zoochosis (abnormal and stereotypical behavior):
-Bar biting
-Neck twisting
-Tongue playing
-Excessive grooming
-Head bobbing, coprophagia
-Swaying
-Pacing
-Circling
-Excessive grooming
-Vomiting
-Self-harm
-Starvation
-Suicide
-Vomiting and Regurgitating (a form of eating disorder)
-Coprophilia and Coprophagia (playing with and eating of feces)
-Lack of apathy (unresponsive or enthusiasm)
-Prolonged infantile behavior
-Abnormal aggressive behavior

Causes of abnormal and stereotypical behavior:
-Separation from natural habitat
-Separation from family and friends
-Lack of natural childhood development
-Enforced idleness
-Direct control by humans
-Loss of life in normal groups
-Drugs and medical fertility control
-Caging

Abnormal Repetitive Behaviour.
ARB is well understood using experimental work on domestic species and observational studies on captive wild animals. The displays and causes of ARB can be categorized using a report from the Centre for Research in Animal Behaviour and HE Animal Management. An animal experiencing abnormal ARB has two forms:

1. Compulsively trying to reach an inappropriate goal [5]. (ie. pacing)
2. A performance linked to an inappropriate motor function [5]. (ie. bar biting)

Studying an animal’s ability to cope with their environment is a method used to determine an animal’s welfare. These methods have been used to remove/rescue certain species from zoo enclosures due to their undeniable inability to cope with their enclosure environment. For example, we have a thorough understanding that elephants and fish often need more room than zoos or aquariums can offer [5].

Our Actions.
Some humans may not have understood the consequences of our actions on these animals. However, now we know. So why do we still have them? In many cases, it is solely for profitable reasons. Similar to: farmed animals, circus animals, carriage horses, sled dogs, and all other animals which are held captive as property, exploited, enslaved, and often abused or murdered. That’s not to say the world isn’t changing; because it is. Sanctuaries, veganism, and animal rights are growing throughout communities globally. We have people who are animal freedom fighters such as the Animal Liberation Front (A.L.F.). They are out on the front line to save animals from cruelty and protect them. If you are interested in who they are check out the ALF: Behind The Mask movie!  To all those who work, volunteer, own/fund animal sanctuaries, and stand up for animal rights when they are not heard. We each have the freedom to choose companies and lifestyles we support through our daily meals and purchases.

References:
[1] http://www.wildlife.org.nz/zoocheck/zoochotic.htm

[2] http://anthro.palomar.edu/evolve/evolve_2.htm

[3] Powell, D. M., & Watters, J.V. The Evolution of the Animal Welfare Movement in U.S. Zoos and Aquariums. Zool Garten N.F. (2017), http://dx.doi.org/10.1016/j.zoolgart.2017.04.007

[4] http://www.biology-online.org/2/14_gene_pool.htm

[5] Paul E.  Rose, Steve M. Nash, Lisa M. Riley. To Pace or not to Pace? A Review of What Abnormal Repetitive Behavior tells us About Zoo Animal Management. Center for Research in Animal Behavior, Washington Singer Labs, University of Exeter. HE Animal Management, Sparsholt, Winchester, Hampshire. Received 23 April 2016, Revised 16 December 2016, Accepted 21 February 2017, Available online 6 March 2017. http://www.sciencedirect.com/science/article/pii/S155878781730045X