The answer in the case of most species is obvious: No. Not when compared to the lifespan of their wild cousins. How could they? The animals are kept in zoos for reasons that have little to do with their welfare or lifespan as individuals.

Unless their habitats have been completely lost, the ideal place for any given animal is his natural home…not a zoo. There’s no argument there.

Though the purpose of zoos in the modern world is not so much to delight and entertain as it is to provide stewardship to imperiled species and to educate humans, it’s worth asking: At what cost?

At the University of Guelph, researchers have been attempting to frame that question by studying the longevity of Indian and African elephants in captivity relative to those in the wild. The study, published in Science on Thursday, includes hundreds of zoos in Europe (and some in Israel).

Though the study’s findings are being hotly debated in the zoo-keeping world, Guelph researchers determined pretty convincingly that elephants live less than they would in the wild—by a long shot.

Indian elephants fared worse according to the study, with half of all members of this species dying by age 19 in the European zoos (compared to age 41 in their natural habitat). In the African species, females were specifically at risk. Though a third of females live beyond age 50 in the wild, no female African elephant in captivity has lived beyond her fourth decade.

Lots of reasons were considered: climate, food sources, obesity (yes, elephants can get obese in captivity), exercise and normal elephant socialization. But the study’s goal was not to reason why, simply to point out the obvious.

One of my favorite radio shows on NPR is Science Friday, a program well known for its nerdy host and top-echelon scientist guests. Yesterday it featured this great story pitting principal study author Dr. Georgia Mason against Paul Boyle, senior vice president for conservation and education at the Association of Zoos and Aquariums in the US.

The sometimes acrimonious debate in this case swirled around the issue of the study’s statistical validity. Given that many of the 4,900 elephants in this study began their lives in zoos in the 1960’s, back when poor husbandry was more the norm, and considering that the wild elephant “control group” live in protected preserves, is this study really comparing apples to apples?

Perhaps not. How could any study like this take droughts and poaching into account? The longevity of elephant species makes a study like this especially difficult. Even so, the dramatic difference in lifespan was published in Science because the data is nonetheless credible and significant.

After all, we do know that zoos impact individual animals adversely. How adversely is the question.

No one is asking zoos to stop doing their job. But if we claim to seek to provide stewardship to these animals, it stands to reason that we should do so with an understanding of what we gain in the bargain…and what we lose.