Chimpanzees' brutal battle for territory leads to a baby boom A rival chimp can die in less than 15 minutes during these deadly territorial fights. New research led by UCLA and the University of Michigan has shown that chimp communities that kill their neighbors to gain territory also gain reproductive advantages. Breakthroughs, discoveries, and DIY tips sent every weekday. Uganda's Ngogo chimpanzees are well known for their "chimpanzee warfare." Primatologists have observed their brutal, lethal fights between 10 or more chimpanzees for decades, deciphering what leads to such violence.

How can we identify groups of primate individuals which could be conjectured to drive social structure? To address this question, one of us has collected a time series of data for social interactions between chimpanzees. Here we use a network representation, leading to the task of combining these data into a time series of a single weighted network per time stamp, where different proximities should be given different weights reflecting their relative importance. We optimize these proximity-type weights in a principled way, using an innovative loss function which rewards structural consistency across time. The approach is empirically validated by carefully designed synthetic data. Using statistical tests, we provide a way of identifying groups of individuals that stay related for a significant length of time. Applying the approach to the chimpanzee data set, we detect cliques in the animal social network time series, which can be validated by real-world intuition from prior research and qualitative observations by chimpanzee experts.

Chimpanzees get more selective over who they associate themselves with as they age, new research reveals. In a study spanning two decades in a Ugandan national park, US experts observed social interactions among 21 wild male chimps, ranging in age from 15 to 58 years. Both chimps and humans prefer to be around the company of old friends and spend less time among new faces, the experts conclude. Ageing male chimps have more mutual and positive friendships than younger chimps, who have more one-sided, antagonistic relationships. Chimps also showed a shift from negative interactions to more positive ones as they reached their twilight years, 'like humans looking for some peace and quiet'.

Scientists have discovered two species of wasps which grow up to four inches (10cm) long and lay their eggs inside other insects. The wasps were found in the jungle in Uganda's Kibale National Park and are among some of the only ones of their type ever discovered. Named Epirhyssa quagga and Epirhyssa johanna, the creatures are part of the rhyssine family, which cannot sting and are harmless to humans. But they are less harmless in their own habitat – their larvae develop inside the offspring of beetles and other wasps and eat them from the inside out. Discoveries of these disconcertingly large wasps are generally rare, but scientists this time found large numbers of both males and females of new types in the forest.