Chimpanzees that had once formed a cohesive community in Uganda split into factions and turned violent, according to a new study. Nearly 30 chimps were killed, including 19 infants.

The long-running conflict in a formerly unified community, the second ever observed, adds to Jane Goodall’s studies about a different chimp war in the 1970s.

A chimpanzee called Trudy who was rescued from her abusive owner is celebrating her 30th birthday. The animal made headlines when circus trainer Mary Chipperfield was found guilty of 12 counts of cruelty relating to the young chimp in Hampshire in 1999.

From her studies, Fiona concluded that the relative absence of creepy-crawlies was the biggest reason chimpanzees build nests. When she slept on the bare ground, she found that just after sunset it became a single crawling, slithering, hopping carpet of insects, which continually interrupted her sleep. “It was unbearable,” she said.

Chimpanzees in Uganda use plants to treat wounds and help injured companions, revealing potential roots of human medicine.