[ad_1]
A poisonous mouse licking deadly toxins on its fur looks like some kind of invented nightmare species. But these creatures are real, and scientists now say they are also unexpectedly affectionate, at least with their own kind.
For would-be predators, the African crested mouse, Lophiomys imhausi, it’s trouble. They inhabit wooded areas in the eastern part of the continent, and people have long known to stay away from these elusive black and white rodents.
“If a dog tried to attack them, the dogs would get sick and die. So that information has been around for a long time,” says Sara Weinstein, a researcher at the Smithsonian Institution and the University of Utah who has worked with colleagues in Kenya to trap. and study rats.
The animals don’t look like a typical city rat at all. “They are actually about the size of a small skunk,” he says. “A lot of these are fluff. They’re pretty blurry.” Like a skunk, these creatures have black and white markings that can serve as a warning. When the animal is threatened, it spreads its fur to expose black and white stripes on the flanks.
Curiously, those hips have rows of weird hairs. They’re much thicker than normal hairs, Weinstein says, “and they have this really cool honeycomb structure.”
That structure appears to allow the hair to act as a sponge to absorb poison, which the rat obtains from a plant and deliberately applies to its body.
This has been known since 2011, when a team of researchers reported they caught a crested mouse and offered it a branch from the local Acokanthera changes tree, also known as “poison arrow tree”. It contains a toxin supposedly powerful enough to kill an elephant when applied to an arrowhead. Scientists watched the rat chew the bark, mixing it with saliva. Then the animal coated its specialized hairs with the dirty mixture.
The discovery thrilled mammologists. “Basically, it’s the only mammal known to date, at least what we know, that co-opts a plant’s toxins to make itself poisonous,” says Adam Ferguson, a mammal expert at Chicago’s Field Museum who says he’s obsessed with these rats. .
Weinstein and his colleagues wanted to confirm that this unusual behavior seen in a single rat was, in fact, widespread in this species. They also wanted to check if this mouse’s health was really unaffected by this poison.
Eventually the research team managed to trap and observe 25 rats. In Journal of Mammalogy, say that about half of them chewed tree branches and applied poison to their hair.
“They did occasionally, but not always,” says Weinstein, who says what causes a mouse to grease itself remains a mystery.
The behavior really seemed to have no negative effect on the animals, who remained perfectly active and healthy within their enclosures, he says, noting that “if I were to go out there and start chewing on this tree, I would get incredibly sick and probably die. “
Scientists had assumed that these rats lived lonely lives, since they are rarely seen and usually seen alone. Then it happened to trap a male and a female mouse who lived in the same area.
When their cages were next to each other, though, “they started doing these really interesting vocalizations that we’ve never heard before,” says Weinstein.
It sure seemed that two of them knew each other and wanted to be together.
When the two rats were placed in the same enclosure, “they started cleaning each other and entered the nest together,” Weinstein says, “which totally changed the way we thought about these animals and their behavior.”
From that point on, if they had trapped an animal in one place, they would have installed other traps to try to trap more, and they often did. Researchers now believe that the creatures can live in bonded pairs and that their young can stay with them for a long time.
“This latest paper is a very nice piece of work,” says Jonathan Kingdon, a zoologist at the University of Oxford who led the team that first observed a mouse chewing the bark and applying poison.
After a childhood growing up in East Africa, Kingdon knew these creatures well enough to be able to describe them in the 1974 work he wrote about African mammals. Yet, he says, there are many unanswered questions that “require attention, especially the precise chemistry and evolutionary history of crested rat saliva.”
Ferguson says this mouse has long been almost “mythical, as it has escaped our understanding, and there has been speculation. But now we are finally trying to figure out what really happens with this mouse.”
He and some colleagues are working to sequence the entire genome of African crested rats, to try to understand what their biological trick is that allows them to accidentally nibble on such a super toxic plant.
“This thing is unique,” notes Ferguson. “As mammologists, biologists and humans in general, we are obsessed with rare things.”
9(MDAzNTg0OTAyMDEyOTc4NzIxNTYxN2U1Yg004))
ARI SHAPIRO, HOST:
Normal rats can already be a little hard to love. Poisonous rats – well, it looks like some kind of made-up nightmare species. But as NPR’s Nell Greenfieldboyce reports, this odd East African rodent is real and, it turns out, surprisingly affectionate.
IN THE GREENFIELDBOYCE, BYLINE: The African crested rat looks more like a skunk than a city rat. Sara Weinstein is a researcher at the Smithsonian Institution and the University of Utah. He trapped these creatures in Kenya, where they live in the forests.
SARA WEINSTEIN: They are actually about the size of a small skunk, so about two pounds. And a lot of that is fluff. They are quite blurry.
GREENFIELDBOYCE: It says like a skunk, they have black and white stripes that serve as a warning. People who live near these animals know they stay away. Rats have a reputation for being bad news.
WEINSTEIN: If a dog tried to attack them, the dogs would get sick and die. So that information has been around for a long time.
GREENFIELDBOYCE: About ten years ago, researchers trapped one of these mice. They had an idea what made these mice so scary. They suspected that a mouse might apply poison to its own fur. They offered the mouse a branch from a local tree known as the poison arrow tree. This plant contains such a powerful toxin that putting it on an arrow can be deadly to an elephant. The rat chewed the bark, mixing plant material with its saliva. Then he applied this disgusting mixture to a row of hair down the side. Weinstein says these distinctive hairs look really weird.
WEINSTEIN: They are a little thicker than normal hair and have this really interesting honeycomb structure.
GREENFIELDBOYCE: The hair acts like a sponge that absorbs the poison. Now, this unusual behavior had only been seen in one rat, so Weinstein and his colleagues wanted to confirm that the others did too. They also wanted to watch the mice for a while after to see if their behavior and health weren’t really affected by this poison, which seemed surprising.
WEINSTEIN: If I were to go out there and start chewing this tree, I would get incredibly sick and probably die.
GREENFIELDBOYCE: The research team eventually managed to trap 25 rats. In the Journal of Mammalogy, they say that about half of them chewed tree branches and applied poison to their fur.
WEINSTEIN: Sometimes they did, but not always.
GREENFIELDBOYCE: And they remained perfectly active and healthy. The researchers also learned something else. They had assumed that these mice lived a lonely life. Then it happened to trap a male and a female mouse who lived in the same area. And when their cages were next to each other …
WEINSTEIN: They started doing these really cool purring vocalizations that we had never heard before.
GREENFIELDBOYCE: Put together in the same enclosure, these mice have started grooming and snuggling.
WEINSTEIN: Which totally changed the way we thought about these animals and their behavior.
GREENFIELDBOYCE: Researchers now believe creatures can live in loving pairs. Also, their young ones may stay with them for a long time. The new findings thrilled Adam Ferguson. He is a mammal expert at the Field Museum in Chicago who says he is obsessed with these rats.
ADAM FERGUSON: Basically, it’s the only mammal known to date, at least, of which we know that it cooperates with a plant’s toxins to become poisonous.
GREENFIELDBOYCE: He and some colleagues are now working to sequence the entire genome of these rodents to try and figure out what their biological makeup is that allows them to accidentally nibble such a super toxic plant. In Greenfieldboyce, NPR News.
(SOUNDBITE OF SONG, “TOXIC”)
BRITNEY SPEARS: (singing) With a taste of your lips, I’m on my way. You are toxic. I’m slipping under. With a taste of a poisonous paradise, I’m addicted to you. Don’t you know that you are toxic? And I love what you do. Don’t you know that you are toxic? Transcript provided by NPR, Copyright NPR.
Source link
