Zoos 'Consuming' Elephants From the wild

Dec. 12, 2008— -- Zoos are "consuming" elephants, says a team of researchers and conservationists who have, for the first time, compared how the captive animals fare in comparison to their wild cousins.

The findings are not good for elephants looking forward to a life in a zoo: their life expectancy is significantly shorter than for those in African and Asian wild or working populations.

Despite the care elephants receive in captivity and the absence of predators, the study found that death rates in Western zoos are greater than birth rates, making the captive elephant population unsustainable. "The zoo population consumes rather than produces elephants," says Georgia Mason of the University of Guelph in Canada.

"We are aware that the zoo population isn't doing as well as we would like it to – that the breeding and survival of young animals is not as good as it should be – and are working hard to address this," says Miranda Stevenson, director of the British and Irish Association of Zoos and Aquariums.

Long-Lived Workers

Captive breeding efforts in Europe are just a decade or two old, Stevenson says, and therefore still improving. She believes the captive population helps understand elephant behaviour and physiology so that wild populations can be managed better.

Mason and collaborators compiled data for nearly half the world's population of captive elephants, focusing on 800 female elephants housed in European zoos between 1960 and 2005.

They compared their survival to that of female African elephants in Kenya's Amboseli National Park, and female Asian elephants in the Burmese logging industry.

Female African elephants live on average 16.9 years in zoos, compared to 56 years in Amboseli. When the researchers factored in human-caused deaths in the park, the average lifespan was 36 years – still significantly longer than in zoos.

Premature Deaths

The life expectancy of wild-born Asian elephants was roughly the same whether they were captured and transferred to European zoos or transferred to the Burmese timber industry. Captive-born elephants, however, lived on average 19 years in zoos, compared to 42 years in the logging industry.

"Asian elephants animals born and bred in zoos have much shorter life spans than those that are wild captured," says Mason. "Something is happening before the age of three or four that programmes zoo-bred animals to die prematurely."

The researchers say their results raise concerns for the viability of captive breeding conservation programmes. For such programmes to fulfil their goal of preserving endangered species, they cannot rely on animals being captured in the wild.

"Amazingly there have not been studies of what matters in terms of the welfare of zoo elephants," says Mason. This will soon change: the British and Irish Association of Zoos and Aquariums is publishing the results of such a study later this week.

Stressed and Overweight

There are a few "smoking guns" in elephant welfare. For starters, zoo elephants have a far smaller range so they get less exercise. Zoo food is different to that in the wild, and is much easier to come by, which could contribute to making zoo elephants obese, a known threat to the captive population.

And there are social factors which could be putting a considerable amount of stress on captive elephants.

In the wild, families of elephants stay together forever and are led by a matriarch. In zoos, females are moved on average every seven years. Mason's study showed that Asian elephants were more likely to die after an inter-zoo transfer, an effect that lasted up to four years.

Mason and colleagues are calling for more quantified research into what factors affect zoo survival and a moratorium on importing elephants from Asia and Africa to western zoos. They also would like to see inter-zoo transfers kept to a minimum.