Wild Things | Science News



Help us keep you informed.

Support Science News.

Wild Things

The weird and wonderful in the natural world

Sarah Zielinski

Wild Things

Wild Things

How a snake named Hannibal led to a discovery about cobra cannibalism

cape cobra cannibalizing another cobra

Scientists working in the Kalahari Desert spotted this cape cobra, which they later named Hannibal, eating a smaller cape cobra. The find set off a search for how common the practice of cobra cannibalism really is.

Sponsor Message

Studying the diet of snakes isn’t easy. The animals are elusive, and they don’t feed all that often. It probably doesn’t help that some of them can be deadly to humans. So perhaps it’s not much of a surprise that scientists hadn’t realized how common one category of snack is for southern African cobras: each other. But once researchers started looking, they realized that cannibalism among cobras happens far more frequently than anyone had thought.

Bryan Maritz, a herpetologist at the University of the Western Cape in Bellville, South Africa, hadn’t set out to study cobra cannibalism. He and his colleagues were conducting a study in the Kalahari Desert of two species of snakes: cape cobras and boomslang.

“The snakes raid these huge colonial social weaver nests and eat all the chicks and eggs,” Maritz says. The researchers want to better understand how the two species use the birds and their nests, and they were looking for snakes that they could implant with radio transmitters.

One day this past January, though, while searching for snakes, the researchers got a radio call from a tour guide who told them where to find a pair of large yellow snakes engaged in a fight. Thinking those yellow snakes might be cape cobras, the team raced to the site. They didn’t find a snake fight but did find one large cape cobra swallowing a smaller one.

“Instead of capturing two potential study animals, we found one well-fed study animal, now known as NN011, or more casually, Hannibal,” Maritz and his colleagues write in a paper published October 1 in Ecology.

This wasn’t the first documented sighting of a cannibalistic cobra, but scientists didn’t think such behavior was common. “The total number of observations of cobras eating in the wild isn’t a big number, and the observations of cannibalism in the wild are even rarer, so I think it’s easy to dismiss as a one-off thing,” Maritz says.

But Maritz had previous inklings that this practice might not be so rare. Before starting the cape cobra-boomslang study, he’d had students dissect museum specimens, and they found a surprising number of cape cobras that had eaten other cape cobras. The discovery of Hannibal, though, persuaded him that he needed to investigate just how common the practice was.

Maritz and his colleagues went looking for reports of cobra diets in research papers, newsletters and museum bulletins, and also solicited stories on Facebook. There are some 30 species of cobras in Africa and Asia, but the team restricted their analysis to six species, including the cape cobra, in southern Africa.

Snake-eating, they found, was common among five of the six species studied, accounting for 13 to 43 percent of the cobras’ diets. Conspecifics, snakes of the same species, represented about 4 percent of all prey items in the study, the researchers found. And because all cobra species share similar diets, the scientists think that cannibalism might be a characteristic shared by even more cobra species.

In all the cannibalism events that the researchers witnessed themselves, both the eater and the eaten were males, leading them to suspect that this behavior may be a male-only trait. More research will be needed to determine if that’s true. But if it is, Maritz says, “I could see it playing a role in competition for resources or mates. What better way to get ahead in life [than to] eat the guy who is taking your food and mating with females that you might want to mate with?”


The animal guide to finding love

By Sarah Zielinski 6:00am, February 14, 2017
Learn to dance, keep an eye on your competition, bring a gift: Animals have some practical advice for finding a mate.
Animals,, Conservation

A diet of corn turns wild hamsters into cannibals

By Sarah Zielinski 9:00am, February 7, 2017
Female European hamsters fed a diet of corn eat their young — alive. They may be suffering from something similar to the human disease pellagra.
Conservation,, Plants

A message to rock climbers: Be kind to nature

By Sarah Zielinski 7:00am, January 18, 2017
Scientists are only just starting to figure out the impacts that the sport of rock climbing is having on cliff ecosystems.

World’s largest reindeer population may fall victim to climate change

By Sarah Zielinski 8:00am, December 23, 2016
Climate change and wolves are driving down the reindeer population in Russia’s Taimyr population.
Animals,, Evolution

Chimps look at behinds the way we look at faces

By Sarah Zielinski 8:00am, December 16, 2016
Humans demonstrate something called the inversion effect when gazing at faces. Chimpanzees do this too — when looking at other chimps’ butts.

Why a mountain goat is a better climber than you

By Sarah Zielinski 12:21pm, December 7, 2016
For the first time, scientists have analyzed how a mountain goat climbs a cliff. Big muscles in the shoulder and neck help a lot, they find.

Now there are two bedbug species in the United States

By Sarah Zielinski 9:00am, November 23, 2016
The tropical bedbug hadn’t been seen in Florida for decades. Now scientists have confirmed it has either resurfaced or returned.

Old bonobos have bad eyesight — just like us

By Sarah Zielinski 2:22pm, November 8, 2016
As bonobos age, they lose their ability to see things close up, a new study suggests.
Conservation,, Animals

City dolphins get a boost from better protection and cleaner waters

By Sarah Zielinski 11:08am, November 3, 2016
Bottlenose dolphins near Adelaide, Australia, are slowly growing in number due to better environmental conditions and better protection.

With climate change, grizzly bears may hibernate less

By Sarah Zielinski 1:00pm, October 25, 2016
New research shows that food availability and weather are driving when grizzly bears enter and exit their dens for hibernation.
Subscribe to RSS - Wild Things