Animal welfare officers yesterday urged zoos to phase out keeping elephants, after two damning reports found the animals suffer serious health problems and die much younger in captivity.
Elephants born and raised in zoos live less than half as long as those living in their native Africa and Asia, despite being protected from predators and having better care, according to one of the reports.
Many of the deaths are thought to be linked to obesity, because the animals are well fed but get very little exercise in their small enclosures. Scientists also blamed high stress levels, which the animals suffer most after being transferred between zoos and being separated from their mothers.
Scientists called on zoos to introduce immediate health checks on elephants to identify obese and stressed animals.
In one study, researchers led by Ros Clubb, a wildlife scientific officer at the Royal Society for the Prevention of Cruelty to Animals, analysed records of 786 Asian and African female elephants kept in European zoos between 1960 and 2005. They then compared the lifespans of the captive animals with Asian elephants used by a logging company in Burma, and African elephants living in the Amboseli national park in Kenya.
Asian elephants born in captivity typically lived for 18.9 years, while those used as working animals in Burma survived for 41.7 years. African elephants also fared worse, living for 16.9 years in captivity and 35.9 years in the wild. When the scientists discounted African elephants killed by people in the national park, the typical lifespan reached 56 years, more than three times as long as those kept in zoos.
"You would expect captive elephants to live at least as long, if not longer, than those in the wild because they are better cared for, but that is not the case. The difference is massive," said Clubb, whose study appears in the US journal Science.
A second report, commissioned by the Department for Environment, Food and Rural Affairs, examined the welfare of 77 elephants in 13 UK zoos. It found that the animals spent 83% of their time indoors and 71 were overweight. Only 11 were able to walk normally.
"We often hear that zoos play a vital role in conserving elephants but patently this is not the case," said Rob Atkinson, head of wildlife science at the RSPCA.
"The new data shows elephants die young in Europe's zoos, and those Asian elephants born in captivity have a poor chance of survival. Surely the way forward is to encourage conservation programmes in native habitats rather than condemn elephants to a shortened and unhealthy existence in our zoos."
He added: "Elephants are having a torrid time in our zoos, judging by this overwhelming evidence, and action must be taken to alleviate their welfare problems as a matter of urgency."
Zoo enclosures for elephants are typically 60 to 100 times smaller than the smallest wild territories. African elephants can roam over 2,000 square miles, and Asian elephants 300 square miles. In captivity, researchers said, elephants are also at risk from infanticide, tuberculosis, herpes and lameness.