Ant colonies have their own personalities, which are shaped by the environment, a US study suggests.
Colonies of several hundred ants show differences in the way they behave, just like individual people do.
The study is published in the journal 'Proceedings of the Royal Society B'.
According to ecologists, having a personality means showing a consistent pattern of behaviour over time.
Researchers from the University of Arizona studied colonies of rock ants across the western US, both by following them in the wild and by taking whole colonies back to the lab.
They found that certain risky behaviours, like foraging widely for food and responding aggressively to a threat, went together, and colonies further north tended to take more of these risks.
The study suggests those more adventurous personalities could be an adaptation to the limited window of activity left by the long, snowy northern winter.