Zoo elephants in the U.S. are so obese, they might go extinct

an elephant butt
CC BY 2.0 TheBusyBrain

A cursory glance over Kari Morfield's office desk would likely raise some questions, and perhaps a few eyebrows. As part an ongoing research about the health and well-being of zoo animals, the wildlife researcher has collected hundreds of photographs of elephants -- specifically, close-ups of their rear-ends.

Apparently, you can learn a lot by studying the 'junk in their trunk'. The one in the back, that is.

According to Morfield, who works as an animal endocrinologist at the Lincoln Children’s Zoo's Wildlife Conservation Research Center, many captive elephants in the U.S. aren't just naturally big, they're in fact suffering from obesity. And like the threats associated with being dangerously overweight in humans, zoo elephants too suffer from cardiac disease, arthritis, and infertility because of it.

But an epidemic of portly pachyderms is a bigger problem than most people had ever stopped to realize.

“In the next 50 years, the captive population will not be viable and will be extinct. In 50 years, there will be no more elephants in zoos,” the researcher tells the Lincoln Journal Star. “The last thing they want to do in zoos is take animals from the wild to stock zoos. We have to take care of the ones we have. We want the population to be self-sustaining.”

As you might imagine, determining the body fat of an elephant is no easy task. But Morfield says she's found a way that doesn't require an extra-long waist tape measure. As it turns out, fatter elephants wear excess weight mostly in their hindquarters. So, after scouring over hundreds of photos of elephant butts, both in the wild and in captivity, Morfield created a scale (from 1 to 5) to describe the normalcy of their body mass.

In the wild, elephants average 2 on the scale; in the U.S. forty percent are 5's.

Morfield notes that obesity is threatening captive elephant reproduction, as the extra weight is leading to infertility. Even among elephants classified as 4's, only half are capable of reproducing. And while 3's are unaffected, there are only two 2's in the entire country.

There are several factors believed to be contributing to elephant obesity. For starters, zoo elephants are far more sedentary than their wild counterparts that regularly walk miles in search of grazing grounds. Also, elephants in captivity are fed a comparably lavish diet of fruits and high-quality (read caloric) hay.

Morfield suggests that zoos make changes to counteract this girthing trend -- such as forcing elephants to 'hunt' for food in their enclosures, and by mixing in lower-quality straw and hay into their diets.

"There are no treadmills large enough for elephants," says the researcher.

While it has yet to be proven that animals currently rendered infertile from obesity could become reproductive with weight loss, dietary changes have restored fertility in humans. And as today's population of elephants in the U.S. continue to die off from other weight-related causes, captive births will help ensure no more elephants need to be plucked from the wild.

“Humans have a choice about their lifestyle. We give elephants a lifestyle. It is only fair to give them a healthy lifestyle," Morfield says. "So far, we are failing them."

Zoo elephants in the U.S. are so obese, they might go extinct
Captive pachyderms are packing on the pounds, and it's putting their very future at risk.

Related Content on Treehugger.com