Thread by @UofUNews

The African crested rat looks adorable, but its fur is packed with lethal poison—just milligrams can kill a human. New study discovered they also have a rich social life.@NationalZoo @museumsofkenya @UUtah @MDeniseDearing @SaraBWeinstein doi.org/10.1093/jmamma… 📷StephanieHiggins

People in East Africa have known the rat to be poisonous but its source was mysterious. A 2011 paper proposed these rabbit-sized rodents sequester toxins from the poison arrow tree Acokanthera schimperi. They’re the only #mammals to use plant toxins for defense.

The 2011 study hypothesized that the rats chew Acokanthera bark and lick the plant toxins into specialized hairs at the center of these stripes. In the photo, the larger, porous center hair is poisonous, compared to the normal ones in the background. PC: @SaraBWeinstein @UUtah

“The initial 2011 study observed this behavior in a single individual. Our main goal was to determine how common this exceptional behavior was.”—@UUtah @MDeniseDearing #mammalogy #rodents #chemicaldefense PC: Stephanie Higgins

For this study, the researchers got ~1,000 hours of rat behavior using motion-activated cameras. For the first time, they recorded multiple rats sequestering Acokanthera #toxins and discovered many traits that suggest they’re social, and likely monogamous—a big surprise.

“Everyone thought it was a solitary animal. I’ve been researching this rat for more than 10 years, so you’d expect there to be fewer surprises”— Bernard Agwanda, curator of #mammals @museumsofkenya, also a coauthor on 2011 paper. “This can carry over into conservation policy.”

At the Mpala Research Centre in Kenya, 1st author @SaraBWeinstein was joined by Katrina Nyawira, 2nd author, now @oxford_brookes. They spent months experimenting to capture the rodents.When they caught a male/female in the same spot, they were thrilled. PC:@MDeniseDearing

“We put these two rats together in the enclosure and they started purring and grooming each other. Which was a big surprise, since everyone we talked to thought that they were solitary. I realized that we had a chance to study their social interactions.”— @SaraBWeinstein @UUtah

Weinstein & Nyawira transformed an abandoned cow shed into a research station and placed cameras in pens, then analyzed every second of footage to build a baseline of normal behavior before seeing any changes after the rats chewed the toxic tree. Photo of chewed Acokanthera bark.

The footage & behavioral observations support a monogamous lifestyle. The paired rats spent more than half the time touching & following each other around. Observations suggest that offspring spend an extended period of time with their parents. @DearingLab @UUtah @museumsofkenya

Multiple rats chewed the poison arrow tree & anointed themselves. It didn’t alter their behavior. “Most people think that it was a myth because of the potency. But we caught it on video! It was very crazy!”— Katrina Nyawira @oxford_brookes @UUtah @NationalZoo @museumsofkenya

The research team is planning future studies to better understand their physiology & behavior. “We are interested in the genetic mechanisms that allow the crested rats and their parasites to withstand the toxic cardenolides,” said co-author Jesús Maldonado @NationalZoo.

“We are looking at a broad range of questions influenced by habitat change. Humans have cleared forests to make farms and roads. We need to understand how that impacts their survival,”— Bernard Agwanda @museumsofkenya

Read our take here: attheu.utah.edu/facultystaff/t… @SaraBWeinstein @MDeniseDearing @DearingLab @NationalZoo @museumsofkenya