Captive elephants are stressed, overweight and dying before their prime, according to a scientific report that is set to inflame the debate over the value of zoos.
The report, to be published in today's edition of Science, says the average lifespan of captive elephants is half that of their wild counterparts, even when poaching is factored in.
While the research is based on European zoo elephants, co-author Georgia Mason of the University of Guelph says it is pertinent globally.
Captive elephants, she says, are stressed by family split-ups. They're overweight. Mental and physical ailments are common.
"They're stressed because they don't have control over their lives," Dr. Mason said.
But Calgary Zoo veterinarian Doug Whiteside challenged the claims, saying the research wasn't strong enough to back up such broad statements. The study also compares captive African elephant survival rates to one of the best-managed elephant populations in the world, he said, ruling out factors of poaching and human encroachment. "The wild picture is not as rosy as critics would paint it."
The paper compares data on 4,500 female elephants in Europe - about half of the world's captive female elephants - to data on wild elephants in Amboseli National Park, Kenya, and elephants working in the Burmese logging industry.
The researchers found that zoo-born African elephants had an average lifespan of 16.9 years. In Ambolesi, the average natural lifespan is 56, but that drops to 35.9 years if "human-induced death" is factored in.
For the more endangered Asian elephants, median lifespans in captivity were 18.9 years, compared with 41.7 years in the Burmese population. The infant mortality rate was also higher for captive Asian elephants, and inter-zoo transfers significantly increased the risk of death.
Canada is home to an estimated 32 elephants at seven zoos. Julie Woodyer, campaigns director for Zoocheck Canada, said the European figures reflect the information collected locally.
"We believe it is the stress of captivity which is killing these animals," Ms. Woodyer said, citing small enclosures, the disruption of social groupings and the restrictions of cold weather as prime stress factors. "It's very frustrating for the elephants in this country."
Zoo populations are not self-sustaining, and need wild elephants to survive, the researchers say. The Detroit Zoo cited the same concern, among many others, when it decided to close its elephant enclosure in 2005 and send its remaining two elephants to a sanctuary.
But some facilities, like African Lion Safari in Flamborough, Ont., say they have a healthy environment and their elephants are thriving. This summer, its herd welcomed Chuck, the first third-generation elephant born in North America.
"It's a philosophy of activity and mental stimulation," said the park's marketing manager, Lori Latter, of its elephant program.
But Dr. Mason said the best place for elephants to live is in their natural home.
"If you want animals to live a long life, the most efficient way to ensure that is to protect them in Africa and Asia, rather than here," she said. "You need to look at the data, not just look into your heart and see how much you care about them."