Tuesday, March 26, 2013

Naked Mole Rat Enrichment

Viewers of our new naked mole rat cam may have noticed an occasional toy or treat in the exhibit chamber. Animal Caretakers call this “enrichment.” This is a term that frequently comes up in our blog posts and perhaps you’ve wondered, "What is enrichment and why is it important?"

Enrichment, as a whole, is something we give animals to bring out their natural behaviors and keep their brains active and the animals engaged. This can range from something on a small scale, such as hiding food for them to forage, or on a large scale, introducing naturalistic objects into their environment for them to manipulate and explore. In these ways, we cannot only enrich the lives of our animals, but also the experiences of our guests as they explore the world of animal life.

Our only mammals at Pacific Science Center, naked mole rats, are a huge focus for our enrichment activities. Their daily need for food and stimulation offer a fun challenge for Animal Care staff, who constantly find new ways to present a fairly simple diet. One way to enrich their lives in captivity is through food-based enrichment activities. These enrichments can range from blocking up tubes with solid tubers that they have to chew through, like they would in the wild, to small pieces hidden within their bedding to encourage foraging behaviors. We also like to make food-based enrichment fun for us too. Sometimes we create food sculptures, like a naked mole rat styled pizza or holiday shaped food that shows our love for them. While our mother told us to never play with our food, she never said that we couldn’t play with the food of others!

Another way that we keep these little guys challenged and active is through physical enrichment: Consistently changing their chamber and tube layout to keep them stimulated. We also provide them with dead ends. Instead of a tube leading into a chamber, it leads into a concrete block that allows them to keep their ever-growing teeth at a healthy shape and size. Physical enrichment also gives naked mole rats the feeling of working to expand the colony as they would in the wild.

The CareFRESH® bedding in their chambers also provides a great enrichment tool. With the bedding, naked mole rats rearrange their own habitat, filling certain chambers while emptying out others. They also keep their keepers enriched by kicking their bedding up into the exhibit through their volcano tube which Animal Care staff then have to vacuum up!

The mole rats are, surprisingly, also enrichment for themselves! Social enrichment is ever-present with our colony of 63 naked mole rats. Watching them interact, in person or via the web cam, reveals the unique eusocial dynamics and individual behaviors of our naked mole rat colony.


  1. just wondering about the concrete block is the a standard concrete mix or have you put vitamin/ mineral compounds in the mix? also have you had any issues with the NMR eating the concrete or chipped teeth.

    1. The concrete has no supplements in it, just slightly sandy concrete. We have made ones with peanuts in the past, but they can go bad. The answers to your following questions indicate why the make up of the block actually isn’t much of an issue. Chipped teeth is actually essentially a goal of having the concrete blocks in the exhibit area. Since naked mole rats are rodents, their incisors continue to grow throughout their entire lives, similar to our fingernails. They are naturally burrowers, typically burrowing teeth first. That chewing process wears down their teeth as they grow, and actually does it in a productive pattern. Naked mole rats only have hard enamel on the front surfaces of their teeth, so their gnawing on things wears down other tooth surfaces faster, leaving a sharp edge on the front.

      Again, since they are adapted to burrowing with their teeth, they are also adapted to chewing things they never have any intention of eating, like dirt and rocks in the ground. Their lips actually close behind their teeth, so many things they chew never actually make it into their mouths. In addition to the concrete blocks, the mole rats routinely chew on the acrylic tubes of their enclosure to the point that we need to regularly replace them. They aren’t ingesting this material either. So while we do what to be careful about what we put into their home, some things can be there that can’t actually be eaten and it is just fine!