Gray rat (Rattus norvegicus) smell to know who their relatives are hungry faster and help them to reach food, reported in PLoS Biology. So these animals increase the likelihood that they someday also will provide a useful service.
Although the number of resources is limited, animals don’t always have to compete for them: in some cases, more advantages brings cooperation, not individual work. Organisms with intelligence sometimes act on the principle “service for service” — though services are not required to be the same. For example, first one individual helps another to get food, and after the second brushing her hair from her nasty caked on substances.
Swiss scientists under the leadership of Michael Taborsky (Michael Taborsky) from the University of Bern found out in 2018, so may do gray rat. But in the new study, they wondered whether the animals choose who to help. Assistance to those who really need it, it is cheaper, they are more likely to return that favor. In addition, it allows not to waste resources on freeloaders.