Mole rats: Teamwork
When they dig, they work in teams. The one at the front gnaws away dislodging the soil behind it where the second member of the team hurls the soil back between its legs onto the third member of the team. The soil is passed in this way until the last member of the line receives it and throws it vigorously out of the entrance of the tunnel. A patch of ground colonized by mole-rats is riddled with small heaps of earth which demarcate the entrance to the burrows.