Tuesday, August 4, 2015

Meeting ethological needs: Conflicting data on orca longevity in captivity

by Frans de Waal

Editor's note: Frans de Waal, PhD, is the Charles Howard Candler Professor of Primate Behavior at Emory University and the Director of the Living Links Center at the Yerkes National Primate Research Center. He is also a member of the United States National Academy of Sciences and the Royal Netherlands Academy of Sciences and a member of the AJOB Neuroscience editorial board. His research focuses on primate social behavior, including conflict resolution, cooperation, inequality aversion, and food-sharing.

de Waal, a leading primatologist, makes an argument here for thinking seriously about the captivity of certain animals such as orcas. Of course, the orca also has a sophisticated mammalian brain. Is the defining criterion of our responsibility to other animals their ecological needs, as de Waal suggests, or is it their cognitive function? What do you think?

There is so much to-do about orcas (killer whales) in captivity, with a drumbeat of voices against humans keeping this species, that it was about time we got some data on longevity. Not that longevity is the only measure to consider with regards to the ethics of keeping these fascinating animals, but since there is the claim out there that orcas in human care live short, stressful lives, there is a need to know the truth.

Source: flickr.com



I am interested in this issue since I support animal keeping for educational and conservation reasons at zoos and aquariums. There are many facilities at which the care for animals is taken very seriously by a dedicated staff. I am not going to defend substandard zoos, but feel there is a place for good zoos that bring urban human populations closer to the animal kingdom and teach the value of wildlife conservation.

Nevertheless, it is clear that some species fare better at zoos than others. Baboons kept on a large island or rock, for example, may be in excellent health, breed successfully, and be able to express many of their natural social behaviors, from squabbling to grooming. Despite the complaint that these animals are not free, there is actually no evidence that they are any less happy or healthy than their wild counterparts. But what about species that cannot express their natural behavior in captivity, such as large birds of prey and vultures, which are prevented from soaring high up in the sky? Zoos have played an invaluable role in preventing the extinction of the California condor, yet putting such a magnificent bird in an aviary still seems far from ideal. This is known as the “ethological needs” argument, named after “ethology,” the study of natural or naturalistic animal (and human) behavior. It is about the expression of species-typical tendencies. A chicken needs to have a surface in which it can scratch and dust bath, a pig needs mud in which it can wallow, and so on.

As an ethologist myself, I am sensitive to this argument, and always wonder which species are so curtailed by captivity in their natural behavior that it applies. Apart from large birds, it may apply to elephants, orcas, other cetaceans, perhaps large felines. How to provide these animals with the appropriate environment? It is much easier to offer a troop of baboons or an otter family a stimulating enclosure that shows off their natural tendencies than a herd of elephants or a pod of dolphins.

Longevity is one way to look at this question. Many primates, for example, live on average considerably longer in captivity than in the wild. For elephants and orcas, however, the same cannot be said. On the contrary, they die prematurely compared to their wild counterparts. This may be due to inadequate care, inadequate environments, or chronic stress. But how solid is this longevity data?

We now have two studies, both published in 2015, intended to answer this question. Unfortunately, they contradict each other. In the Journal of Mammalogy, a study compared Sea World’s orca record with what we know about the same species in the North Pacific. It was found that calf survival to two years of age was better in captivity than in the wild and that overall survival at Sea World has steadily gotten better, probably owing to improved husbandry and veterinary care. The study claims that survival is presently indistinguishable from that of wild populations. A second study, published in Marine Mammal Science, also notes improvement in captive survival, but claims substantial differences in the upper age range. In captivity, only 7% of females get older than 40 years, whereas in the wild this proportion is said to be between 41 and 75%. If true, captivity still negatively affects health, at least physically, but probably also psychologically.

Source: Wikimedia Commons

Even if one day we could extend the lives of large cetaceans in captivity, however, this still doesn’t solve the issue of ethological needs. One could still argue that so long as we are unable to provide these animals with a species-appropriate environment in which they can live in large pods, travel distances, and employ their echolocation capacities, it is unethical to keep them. Despite being a zoo supporter, I could live with such a conclusion.

References

Jett, J., & Ventre, J. (2015). Captive killer whale (Orcinus orca) survival. Marine Mammal Science. doi: 10.1111/mms.12225

Robeck, T. R., Willis, K., Scarpuzzi, M. R., & O’Brien, J. K. (2015). Comparisons of life-history parameters between free-ranging and captive killer whale (Orcinus orca) populations for application toward species management. Journal of Mammalogy. doi:10.1093/jmammal/gyv113

Want to cite this post?

De Waal, Frans. (2015). Meeting ethological needs: Conflicting data on orca longevity in captivity. The Neuroethics Blog. Retrieved on , from http://www.theneuroethicsblog.com/2015/08/meeting-ethological-needs-conflicting.html

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