Crested rats don’t simply chew tree bark that’s dangerous enough to kill an elephant. The rabbit-sized rodents dribble and lick the poisonous drool into their long rat fluff for a weaponized hairstyle. Yet these hazardous rats, which scientists assumed were loners, end up to have a close and cuddly family life. They even purr.
Chewing on bark or other parts of East Africa’s arrow toxin trees gives the rats hazardous saliva to apply to specialized zones of fur. The contaminants sink in to permeable, easily separated hairs on the rat’s flanks. Any predator foolish adequate to bite a Lophiomys imhausi gets a hairy mouthful of bitter toxic substances that human poachers use on arrows for searching huge game.
The rats “have the character of something poisonous,” says ecologist Sara Weinstein, who studied them throughout a Smithsonian fellowship at the Mpala Research Center in Kenya. The rats are more most likely to jog away from problem or stand their ground, hissing, growling and grunting.
Trapping crested rats took some experimenting, says ecologist Katrina Nyawira, who worked on the project with Weinstein prior to relocating to Oxford Brookes University in England. “Sometimes we ‘d set traps for about two weeks and just get one specific and, trust me, that would be a win.”
Researchers set traps in an odd variety of locations, from remote spots in the Kenyan savanna to behind someone’s bed room door, Nyawira and Weinstein recognized that the common success aspect was access to arrow toxin trees ( Acokanthera schimperi).
With glossy, green leaves formed like fat teardrops, this widespread shade tree is a cousin of the North American milkweeds that offer king butterfly caterpillars their defensive toxins. From roots to shoots, the arrow poison tree brings potent cardenolides that can give prospective predators a cardiovascular disease.
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When Weinstein and Nyawira had actually trapped a crested rat for a few days of video observation, the scientists tucked some shreds of the lethal tree bark and roots in the temporary cages. Video cameras periodically caught a nocturnal rat touching up its toxin hairs.
Weinstein questioned if the 25 animals they captured paid some price for licking toxins: “Do they get sick and need to sleep to sleep it off?” The videos, however, total showed no additional naps, no sluggishness or other obvious modifications in behavior after hair care. For crested rats, poison really might be just mousse.
How these rats stand up to the stuff is an ongoing mystery, with lots of speculation. This species’ stomach, for example, has chambers more “like a cow … than your typical pizza rat’s,” says Weinstein, now at the University of Utah in Salt Lake City.
She had not prepared to study crested rat home life, but one why-not impulse changed that. Weinstein once reset a trap in the exact same place she had just captured a crested rat. She ‘d heard that the rats were singular, so her first catch should have emptied the area. Yet she rapidly caught a second rat in the same area.
” We put the two rats sort of next to each other,” states Weinstein, “They start purring– this vocalization that we’ve never heard prior to.”
” They very much looked as if they wanted to be together,” she recalls. One was male, the other woman. When Weinstein enabled the rats into the very same cage, the 2 started grooming each other. One started following the other around, and the couple eventually retired to the cage’s personal retreat, a nest box.
Over the course of a number of months, Weinstein and Nyawira ultimately caught four more male-female sets. 2 sets had children, and each household cuddled together when reunited in captivity. In videos, pair members stayed close, spending about half of their waking time within simply 15 centimeters of each other, the scientists reported online November 17 in the Journal of Mammalogy.
Videos inside the nest box looked particularly relaxing. Pairs bundled together in nose-to-tail swathes of fluff “like a big scarf,” Nyawira says. Their hair is “actually soft, like cat’s fur.” Or as Weinstein puts it: “They’re extremely cute.”