Chimpanzees exaggerate their screams when under attack

Oct 16, 2007

Research by the University of St Andrews shows that chimpanzees vary their screams depending on the severity of the attack and that they can exaggerate the nature of the attack, but only if higher ranking group members are in the audience. The way they scream provides nearby listeners with important cues about the nature of the attack.

The research team, comprising of Dr Katie Slocombe and Dr Klaus Zuberbuhler, found that victims' screams change in acoustic structure according to the severity of aggression experienced. Screams given in response to severe aggression (chasing or beating) are longer, higher in frequency and given in longer slower bouts than screams given to mild aggression (charges and threats).

The study, conducted with wild chimpanzees in Budongo Forest, Uganda, also shows that victims are sensitive to the composition of the audience and modify the structure of their screams accordingly. When faced with severe aggression, victims modify their screams to exaggerate the level of aggression faced, but only if there is a chimpanzee in the audience who is equal or higher ranking than the aggressor (ie a chimp capable of challenging the aggressor and helping the victim). This audience effect only occurs with severe aggression, not mild aggression, showing they only modify their calls when they most need help.

Dr Slocombe said, "We conclude victims use screams flexibly to recruit help from others and have a complex understanding of third party relations. They know exactly who can challenge who, and this knowledge of social relationships influences their vocal production. This shows there is more flexibility in their vocal communication than previously thought".

The study is published in the Proceedings of the National Academy of Sciences (Monday, October 15, 2007).

Source: University of St Andrews

Explore further: Investigators insert large DNA sequence into mammalian cells

Related Stories

Solar Impulse 2 pilot becomes aviation legend

7 hours ago

At 62 years of age, Swiss Solar Impulse 2 pilot Andre Borschberg has made aviation history with a record breaking solo flight across the Pacific that he has called "an interior journey".

Facegloria: Facebook for Brazil's Evangelicals

7 hours ago

Fluffy clouds waft across a blue sky as you log in and while you chat with friends, Gospel music rings out: welcome to Facegloria, the social network for Brazilian Evangelicals.

Mexico City proposes regulations for Uber

7 hours ago

Mexico City is proposing regulations that would allow Uber and other smartphone-based ride-sharing apps to operate, while requiring drivers and cars to be registered, the city's Office of Legal and Legislative Studies said ...

Researchers discover new mechanism of DNA repair

21 hours ago

The DNA molecule is chemically unstable giving rise to DNA lesions of different nature. That is why DNA damage detection, signaling and repair, collectively known as the DNA damage response, are needed.

Recommended for you

Mitochondrial metagenomics: How '-omics' is saving wild bees

5 hours ago

Mitochondrial genome (mitogenome) database demonstrated its great value on detecting wild bees in UK farms via mitochondrial metagenomics pipeline, a new approach developed by scientists from the China National Genebank (CNGB), ...

The role of species competition in biodiversity

6 hours ago

(Phys.org)—Over long spans, biodiversity is a fluid and shifting balance of species and influences. Species diversification occurs in response to a host of complex factors, both biotic and abiotic, and ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.