The African-crested giant rat is hardly the continent’s most fearsome-looking creature. The rabbit-sized animal resembles a gray puffball crossed with a skunk. However, its fur is packed with a poison so lethal that a few milligrams can eliminate a human or fell an elephant. In a paper that’s published recently, the University of Utah, National Museums of Kenya, and Smithsonian Conservation Biology institute researchers found the African crested rat was the only mammal known to sequester plant toxins for chemical defense. They even uncovered an unexpected social life. These rodents appear to be monogamous and may even form small families with their offspring.
The Giant Rat Strikes Back
When threatened, the African crested giant rat lives up to its name and erects a crest of hair on its back. This way, it reveals a warning on its flanks – black and white stripes running from neck to tail. A study from 2011 hypothesized that the rats licked the plant toxins and chewed the Acokanthera bark. In more recent research, specialists trapped 25 African crested rats, the largest sample ever trapped. After this, the researchers documented nearly 1,000 hours of rat behavior. They recorded multiple rats sequestering Acokanthera toxins. They discovered many traits that suggested the rats were monogamous and social.
The Rich Social Life of the Giant Rat
As a postdoctoral fellow, Sara Weinstein, lead author, and Smithsonian-Mpala postdoctoral researcher, first searched for the rats with camera traps. She found that they rarely triggered the cameras. Katrina Nyawira, who is the second author of the paper and now a graduate student at Oxford Brookes University, joined her in the experiment. They spent months experimenting with live traps so they could capture the elusive rodents. They even talked to ranchers and rangers to ask whether they had seen anything. Eventually, loading the traps with smelly foods like peanut butter, vanilla, and fish did the trick.
The behavioral observations and the footage strongly support a monogamous lifestyle. The rats share many of the traits common among monogamous rodents: a long life span, large size, and a slow reproductive rate. Also, the researchers trapped a few large juveniles in the same locations as adult giant rats, suggesting that offspring spend an extended period of time with their parents. The paired rodents spent more than half of their time touching each other and following each other around.
Bernard Agwanda, curator of Mammals at the Museums of Kenya and co-author of the 2011 research reveals that he is building an exhibit at the Museums of Kenya so he can raise awareness about this unique poisonous giant rat.