They're So Adolescent!

At a recent staff meeting, Life Sciences staff commented that the naked mole-rat chambers have been looking grubby lately, even shortly after a fresh cleaning. At first this was simply meant as a slightly rueful observation. But as we discussed it, it became clear that the behavior of one group of animals is creating most of the mess.



The youngest colony members are now as large as the smallest of the adults in the colony. As they transition from juveniles into fully active colony members, these animals are showing behaviors that will help them be accepted in the group.

To a human, some of these behaviors may sound odd. The youngsters go into the communal latrine area and roll in the waste material they find there. Then they run through the tunnels tracking this mixture of bedding and debris. Wherever they go, there is a mess.


What could be the social advantage to a young naked mole-rat in coating itself in liquid from a communal potty? The answer starts to form when we think about where they live. Naked mole-rats’ habitat is underground in near total darkness. In their tunnels, it is impossible to recognize colony-mates by sight. One of the primary forms of identification is odor. Animals that smell like the colony are accepted; those that smell different may be rejected or worse, attacked. So rolling in the most odor-intense area makes a certain amount of sense.

As babies and youngsters, the mole-rats may have been so unthreatening that the colony accepted them without much difficulty. But as they become larger, it is important to the older colony members to recognize them as friendly.


For readers who have never had the pleasure, we can try to describe the odor of the colony. Naked mole-rats get all the water they need from their food, so their urine is extremely concentrated. It is pungent but not ammonia-y. It has a top note of sawdust and mouse, with a musky base note.

In the harsh outdoor habitat where they evolved, leaving the colony is extremely risky. Staying in the colony is much safer – if you don’t mind the smell.