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(C) The Field Museum

Tooth Decay May Have Turned Tsavo Lions into Man-Eaters

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(C) The Field Museum

Looking for good motivation to brush and floss? Mammal experts say the infamous lions that killed dozens of rail workers in Kenya in 1898 may have been driven by dental disease. They published a report on the unfortunate beasts in the journal Scientific Reports.

There were only two of them, but the damage they did was both extensive and terrifying. “I could plainly hear them crunching the bones,” Lieutenant Colonel John Patterson wrote in his diary, “and the sound of their dreadful purring filled the air and rang in my ears afterwards.”

Patterson with one of the Tsavo lions. Image Credit: The Field Museum

Patterson eventually killed the lions, and their remains were preserved for scientific study. Today, the two skulls are kept in the collection of Chicago’s Field Museum so scientists can study them.

The Field Museum

Historians have long believed that the lions turned to human prey out of desperation when a famine eliminated their usual sources of food. If this was the case, the lions would have relished every last bite of every animal they killed, including the bones.

But when Field Museum researchers examined the Tsavo skulls, they began to suspect that the lieutenant’s “very vivid recollection” may have been at least slightly exaggerated, as the lions had clearly not been crunching anything. The microscopic signs of wear and tear that accompany regular hard use were nowhere to be found in the lions’ jaws.

They did, however, find evidence of dental problems. One lion had broken a canine tooth several years earlier, was missing three incisors, and had a periapical abscess, or pus pooled around the root of a tooth. The other had a fractured upper left carnassial (the equivalent of a molar) and exposed pulp (tissue at the center of a tooth).

Bruce Patterson (no relation) is the museum’s curator of mammals. He and his colleagues think the Kenyan lions’ suspiciously smooth teeth and dental injuries could have played a role in their attacks on humans. These types of injuries aren't uncommon, and they can be painful.

“Lions normally use their jaws to grab prey like zebras and wildebeests and suffocate them,” he said in a statement. If you’ve got a mouthful of hurt, you’re not going to leap face-first at a kicking wildebeest. “Humans are so much easier to catch,” Patterson said.

“We humans like to think we’re at the top of the food chain, but the moment we step off our paved streets, these other animals are really on top.”

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Animals
This Octopus Species in Northern Australia Can Hunt on Dry Land
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YouTube

Most octopuses live in the ocean—but in northern Australia, a small, shallow-water species takes to land in search of food. Abdopus aculeatus is the only octopus that’s specially adapted to walk on dry ground. Using its long, sucker-lined arms, the slimy sea creature pulls itself along the shoreline as it searches tide pools for crabs.

Witness Abdopus aculeatus in action by watching BBC Earth’s video below.

[h/t BBC Earth]

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Weather Watch
Rising Temperatures Are Killing Off African Wild Dogs
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Over the last few decades, images of fluffy white harp seals, polar bears, and penguins have become shorthand for climate change's creeping destruction of our planet. But the poles aren't the only ecosystems in danger. A new study published in the Journal of Animal Ecology finds that rising temperatures near the equator are making it much harder for African wild dogs to survive.

"When people think about climate change affecting wildlife, they mostly think about polar bears," lead researcher Rosie Woodroffe of the Zoological Society of London told The Guardian. "But wild dogs are adapted to the heat—surely they'd be fine."

To find out, Woodroffe and her colleagues analyzed data from packs of African wild dogs (Lycaon pictus) in Kenya, Botswana, and Zimbabwe. The dog packs have been under scientist surveillance for years—some since the late 1980s—and at least one dog per pack is fitted with a radio collar.

The researchers overlaid information about local weather and temperature with data on the dogs' hunting habits, the size of each litter of pups, and how many pups from each litter survived.

These dogs are creatures of habit. Adults rise early and leave the den for a morning hunt. They range over their large territories, chasing antelopes. At midday, when the Sun is highest, they return to their pups with food. They may go out again in the evening as the temperature drops.

But like the polar bears' glaciers, the dogs' environment is gradually heating up. All three countries saw a temperature increase of about 1.8°F over the study period. This may not sound like much, but for the dogs, it was plenty. Between 1989 and 2012, the number of pups per litter in Botswana surviving to their first birthday dropped from 5.1 to 3.3. Dog packs in Zimbabwe saw a 14 percent decrease in pup survival; in Kenya, the rate declined by 31 percent.

"It's really scary," Woodroffe said.

"If you are an animal who makes your living by running around really fast, obviously you are going to get hot. But there are not enough hours in the day anymore that are cool enough to do that. It is possible that some of these big areas will become too hot for wild dogs to exist."

Woodroffe and her colleagues were not anticipating such clear-cut results. "It is shocking and surprising that even right on the equator these effects are being seen," she said. "It illustrates the global impact of climate change." 

[h/t The Guardian]

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