It may be difficult for many people to imagine a world without zoos, as they have existed for many years, far exceeding any living human’s age. According to historical records, the first instance of a large collection of animals for human entertainment occurred during an enormous procession organized to honor the god Dionysius staged at Alexandria in 275 BC by Ptolemy II Philadelphos, the second Greek king of Egypt. Thousands of years later, in 1751, a menagerie was created in Vienna, Austria (which exists today as Tiergarten Schoenbrunn), and is now recognized as the world’s oldest continuously operating zoo.
The Antiquated Design of Zoos Dating Back Centuries Still Persists
As the presence of zoos has largely become the “norm” in many parts of the world, so, too, has the design of them. This is despite the advancement of animal biology and welfare science indicating that antiquated design often ignores or conflicts with the basic needs of the animals zoos hold captive.
By design, and largely for what are promoted as “educational” purposes, zoos often group animal exhibits based on shared geography, oversimplified versions of similar climates, or comparable distribution of animals. For example, many zoos have areas entitled “African Savannah,” “Asian Rainforest,” or “South American Jungle” or similar, but these are little more than design themes that bear no meaningful resemblance to the areas they claim to replicate. These themes also force animals to live unnervingly close to animals that would be their enemies, competition, or food in the wild.
Zoo Design Negatively Impacts Animal Welfare
Designing zoos in this way negatively impacts animal welfare, as the nature of these broadly themed exhibits requires solitary, predatory, and prey species to coexist in unnatural ways that conflict with their many evolved behaviors to thrive in the wild. Additionally, the measly square footage of zoo enclosures does not even come close to how far away these animals would typically be from each other in the wild on a typical basis. As explored in our new report, Clawing at the Cages: Big Cats in Zoos (April 2024), big cats exemplify some of the most extreme examples of the detrimental effects of this problematic zoo design; as most big cat species are solitary (except lions, who form social and familial prides) and highly territorial. By design, zoos actively prevent these natural, species-specific behaviors from occurring, and often force animals to live in unnatural social groupings or near other solitary predator or prey species due to the limitations of the captive environment.
Natural Predator/Prey Dynamics Are Disturbed in Zoo Captivity
In the same ways big cats have evolved to use scent marking and vocalizations to establish their territory to warn other big cats, prey have simultaneously evolved to detect these chemical warnings to avoid such spaces. Research confirms that the presence of predators can induce extreme stress and powerful physiological responses in prey, including the following distinctive behavioral effects: inhibition of activity, suppression of non-defensive behaviors like foraging, feeding, and grooming, and movements to locations where such odors are not present. Further, and of particular concern to anyone responsible for caring for animals in captivity, predator odors can have profound effects on the endocrine system of prey animals by suppressing testosterone and increasing levels of stress hormones including corticosterone and Adrenocorticotropic hormone (ACTH). Experiencing prolonged states of stress can decrease immune system function and lead to a higher susceptibility to numerous chronic diseases that can cause long-term physical harm and psychological distress.
To communicate with other members in their species, tigers have scent glands on their tails, paws, and face, and often leave olfactory signals for other tigers using various methods including urine spraying, scraping surfaces with deposits of urine, feces, or anal gland secretions, clawing, cheek rubbing, and vegetation flattening. In addition to these chemical tactics, tigers also often engage in nighttime patrols of their territory. During these patrols, they may renew scent marks and vocalize to reinforce their ownership of the area. In the wild, territorial patrols help deter other tigers from entering established territories, while simultaneously alerting prey to their presence and proximity. One can imagine the elevated frustration level tigers and other big cats in captivity must experience when constantly smelling the “territorial” markings of other big cats in a zoo (without the option to properly defend it), making them constantly aware of their presence.
Within the zoo industry, there is the assumption that predator and prey species (or multiple solitary/territorial predator species) will habituate to each other over time in a captive setting. Studies have confirmed, however, that prey species retain awareness of a predator regardless of the level of exposure. One study illustrated this effect by demonstrating a difference in behaviors exhibited by prey animals (five species of African ungulates) when a predator (African lion) was visually absent versus visually present. The authors discovered that prey spent less time with their heads down when the predator was present, which allowed more time for predator surveillance of potential risk. These results indicate that prey animals experienced increased stress levels when predators were visually present due to the extensive behavior modifications demonstrated by the prey animals.
Valerio the Jaguar’s Escape and Subsequent Hunting Rampage Emphasizes that Natural Predator/Prey Behaviors Remain in Captivity
In 2018, a male jaguar named Valerio escaped his enclosure at the New Orleans Audobon Zoo and killed nine animals, including three foxes, five alpacas, and one emu. Luckily, zoo staff tranquilized Valerio and secured him before any visitors entered the zoo grounds, and no humans were hurt during his escape. The zoo’s managing director believes that Valerio escaped by biting through a steel-cable barrier that comprised the roof of the habitat, and then slipped through the resulting 8 inch by 10-inch gap left in the cables. Officials were unsure how long Valerio roamed free before the escape was discovered. This incident confirms that animals retain their natural instincts, like hunting and killing live prey, despite being confined to a captive environment. Valerio lived his entire life in zoos; he was born at the San Diego Zoo in 2015. Troublingly, the animals targeted as Valerio’s prey did not have any opportunity to escape the fatal attacks during this incident.
Every single aspect of captivity causes animals in zoos to live unfulfilling and miserable lives; the too-small enclosures, lack of mental stimulation, inability to move freely, unnatural social groupings, and inappropriate, largely exploitative interactions with humans all cause animals to suffer in unimaginable ways. Join us in pledging not to go to zoos or aquariums in efforts to prevent future animals from entering this damaging industry that only values animals for their worth in dollars despite emerging science indicating that zoos are literally killing them.
Read our report, Clawing at the Cages: Big Cats in Zoos.
Sign our petition to the USFWS to stop instances of dangerous public interactions with big cats.
Keep Wildlife in the Wild,
Devan
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