Here's a lovely study I happened upon today.

We all know that Meerkats have lookouts to warn of the approach of predators.  There has been debate recently as to whether this behaviour is altruistic (warnings benefit other group members) or self serving (lookouts don't tend to get eaten).

This study (link below) tends to support the altruistic view.  Observations on a troop made in the days before and after a new batch of pups left the den to join in foraging expeditions showed a marked increase in lookout behaviours once the pups were in the group.

http://www.cam.ac.uk/research/news/research-suggests-meerkat-predator-scanning-behaviour-is-altruistic