Baby sea turtles work together to dig their way out of sandy nests, and the more of them there are, the less energy they use doing it.
We knew of this group-digging behaviour, called social facilitation, for a long time, but the reasons for teamwork were unclear. Possible explanations included speeding up nest escape or helping the turtles emerge together to swamp awaiting predators on the beach. Read more in New Scientist.