- Chimpanzees live in Kibale National Park, Uganda.
- A large group later split into two groups.
- One group attacked and killed many former friends.
- The attacks began after rising aggression between subgroups.
- The group split into two parts.
- The groups then stopped meeting and breeding.
- Researchers have followed them for many years.
- Scientists were surprised by violence among former allies.
- Long-term study helped show the change.
- The study raises questions about social behaviour.
Difficult words
- chimpanzee — a large wild ape that lives in AfricaChimpanzees
- split — to divide into two or more parts
- attack — to hurt or try to harm someone or somethingattacked, attacks
- aggression — angry or violent behaviour toward other animals or people
- breed — to produce young animals or have babiesbreeding
- researcher — a person who studies animals or groupsResearchers
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- Have you ever visited a national park?
- Do you think animals can be friends?
- Would you like to watch animals for many years?
Related articles
New commercial bee feed improves winter survival
A study published in Insects found that a new, nutritionally complete commercial feed helped honey bee colonies stay healthier through two winters and the California almond pollination, reducing winter losses and raising hive productivity.
Band of Holes at Monte Sierpe: an Indigenous accounting system?
New evidence suggests the Band of Holes at Monte Sierpe in southern Peru was part of a pre‑European Indigenous system for accounting and exchange. Researchers used sediment analysis and drone images to reach this conclusion.
Gum ingredients help tilapia cope with cold
Researchers tested lecithin and Arabic gum as feed additives for tilapia and found they improved growth, survival and cellular responses to cold. Experts say the approach may help farms in cooler, subtropical areas but not very cold regions.