Nov 20, 2020 08:04 AM
https://www.eurekalert.org/pub_releases/...111920.php
INTRO: The African crested rat (Lophiomys imhausi) is hardly the continent's most fearsome-looking creature -- the rabbit-sized rodent resembles a gray puffball crossed with a skunk -- yet its fur is packed with a poison so lethal it can fell an elephant and just a few milligrams can kill a human. In a Journal of Mammology paper published today, the University of Utah, Smithsonian Conservation Biology Institute, and National Museums of Kenya researchers found the African crested rat is the only mammal known to sequester plant toxins for chemical defense and uncovered an unexpected social life--the rats appear to be monogamous and may even form small family units with their offspring.
"It's considered a 'black box' of a rodent," said Sara Weinstein, lead author and Smithsonian-Mpala postdoctoral fellow and postdoctoral researcher at the University of Utah. "We initially wanted to confirm the toxin sequestration behavior was real and along the way discovered something completely unknown about social behavior. Our findings have conservation implications for this mysterious and elusive rat."
People in East Africa have long suspected the rat to be poisonous. A 2011 paper proposed these large rodents sequester toxins from the poison arrow tree (Acokanthera schimperi). A source of traditional arrow poisons, Acokanthera contains cardenolides, compounds similar to those found in monarch butterflies, cane toads and some human heart medications. Cardenolides, particularly the ones in Acokanthera, are highly toxic to most animals.
"The initial 2011 study observed this behavior in only a single individual. A main goal of our study was to determine how common this exceptional behavior was," said co-author Denise Dearing from the University of Utah. When threatened, the African crested rat lives up to its name and erects a crest of hair on its back to reveal a warning on its flanks--black and white stripes running from neck-to-tail on each side of its body. The 2011 study hypothesized that the rats chew the Acokanthera bark and lick the plant toxins into specialized hairs at the center of these stripes.
In the new study, researchers trapped 25 African crested rats, the largest sample size of the species ever trapped. Using motion-activated cameras, they documented nearly 1,000 hours of rat behavior. For the first time, they recorded multiple rats sequestering Acokanthera toxins and discovered many traits that suggest the are social, and likely monogamous. "Everyone thought it was a solitary animal. I've been researching this rat for more than ten years, so you would expect there to be fewer surprises," said Bernard Agwanda, curator of Mammals at the Museums of Kenya, co-author of this study and the 2011 paper. "This can carry over into conservation policy." (MORE)
INTRO: The African crested rat (Lophiomys imhausi) is hardly the continent's most fearsome-looking creature -- the rabbit-sized rodent resembles a gray puffball crossed with a skunk -- yet its fur is packed with a poison so lethal it can fell an elephant and just a few milligrams can kill a human. In a Journal of Mammology paper published today, the University of Utah, Smithsonian Conservation Biology Institute, and National Museums of Kenya researchers found the African crested rat is the only mammal known to sequester plant toxins for chemical defense and uncovered an unexpected social life--the rats appear to be monogamous and may even form small family units with their offspring.
"It's considered a 'black box' of a rodent," said Sara Weinstein, lead author and Smithsonian-Mpala postdoctoral fellow and postdoctoral researcher at the University of Utah. "We initially wanted to confirm the toxin sequestration behavior was real and along the way discovered something completely unknown about social behavior. Our findings have conservation implications for this mysterious and elusive rat."
People in East Africa have long suspected the rat to be poisonous. A 2011 paper proposed these large rodents sequester toxins from the poison arrow tree (Acokanthera schimperi). A source of traditional arrow poisons, Acokanthera contains cardenolides, compounds similar to those found in monarch butterflies, cane toads and some human heart medications. Cardenolides, particularly the ones in Acokanthera, are highly toxic to most animals.
"The initial 2011 study observed this behavior in only a single individual. A main goal of our study was to determine how common this exceptional behavior was," said co-author Denise Dearing from the University of Utah. When threatened, the African crested rat lives up to its name and erects a crest of hair on its back to reveal a warning on its flanks--black and white stripes running from neck-to-tail on each side of its body. The 2011 study hypothesized that the rats chew the Acokanthera bark and lick the plant toxins into specialized hairs at the center of these stripes.
In the new study, researchers trapped 25 African crested rats, the largest sample size of the species ever trapped. Using motion-activated cameras, they documented nearly 1,000 hours of rat behavior. For the first time, they recorded multiple rats sequestering Acokanthera toxins and discovered many traits that suggest the are social, and likely monogamous. "Everyone thought it was a solitary animal. I've been researching this rat for more than ten years, so you would expect there to be fewer surprises," said Bernard Agwanda, curator of Mammals at the Museums of Kenya, co-author of this study and the 2011 paper. "This can carry over into conservation policy." (MORE)