Rats play tit-for-tat when looking for help from others in their species, according to a new study.
Researchers from the universities of St Andrews in Fife and Bern, Switzerland, found the creatures are happy to help each other out – but only if another rat helps them out first.
After a series of tests to determine co-operation levels, the study concluded rats “literally play quid pro quo when doing favours for one another”.
Dr Manon Schweinfurth of the School of Psychology and Neuroscience at St Andrews led the research.
She said: “We asked what rats remember to reciprocate help with co-operative partners.
“Interestingly, they co-operated based on the last encounter with a partner instead of integrating several encounters.
“To check whether this might be due to a lack of memory capacity, we tested whether rats remember the outcome of encounters that had happened three days before.
“Co-operation was not diminished by the intermediate time interval.
“This shows that rats can remember what happened in the distant past, but only use the most recent encounters with a partner.”
It is the first such study showing how animals behave this way to reduce their load.
Dr Schweinfurth added: “We conclude that rats reciprocate help mainly based on most recent encounters instead of integrating social experience over longer time-spans.
“This is in line with how humans co-operate when it is difficult to remember the exact behaviour of several interactions with partners.
“Given that this is the first study in which animals experienced a partner with conflicting co-operation experience, future studies are needed to understand how common this behaviour is.”
The study – Rats play tit-for-tat instead of integrating co-operative experiences over multiple interactions – is published in Proceedings of the Royal Society on Wednesday.