Thursday, August 27, 2009
The biggest news of the summer at Pacific Science Center’s Life Sciences department has got to be the baby naked mole-rats born on August 6. Because many people have been asking about the babies’ welfare, Life Sciences Manager Sarah Moore has provided a week-three update.
**This article was updated on August 31, 2009. See below**
Sometime around August 23 the mole-rat pups passed a very important milestone. That was when staff members spotted them eating solid food.
Their first foods, sweet potatoes and jicama, are both fairly firm, crunchy food, not what we think of as a good texture for infants. However, there were softer foods available, such as thawed frozen peas and “dough balls” made from baby cereal mixed with nutritionally complete rodent food. Yet the pups chose something very chewy.
These little animals are already growing teeth. Like other rodents, naked mole-rats’ teeth continue to add enamel throughout their lives. The process of chewing helps them keep their teeth even and at the right length, so chewing hard foods probably feels good to them, even as babies. Having good, functional teeth is a sign that our babies are developing well.
As they start eating more adult food, the pups will show a very unusual behavior. They will start begging older animals for cecotropes, a special kind of pellet produced by the digestive systems of mature naked mole-rats. The pellets give the pups valuable beneficial organisms (probiotics) that help them digest their food. Without them the babies would not be able to get the nutrients they need. Readers with pet rabbits may have observed them eating their own cecal pellets for the same reason.
The pups are also starting to move around the chambers on their own. This is a positive development as some of the workers recently worked their way through one of the barriers that was separating the nursery from the main colony. The entire colony is now together with the new mother and her pups. So far their behavior appears healthy and normal.
Our Animal Care team will continue to monitor them closely to ensure that the pups are not harmed by the many large workers that are now surrounding them. Come visit our exhibit at Pacific Science Center and check back on this blog for more updates as these adorable babies continue to grow.
On Saturday August 29, our Animal Care staff discovered that one of the naked mole-rat pups had died. Unfortunately we were not able to bring it to the vet for a necropsy, so we will not know the exact cause of death. This is a reminder that the mole-rat pups are still in a fragile stage of their lives. We are approaching day 28. By September 11, day 36, they will be entirely eating solid food. That will be the second time of high risk. We have to hope the cecotropes did their work as a lot of mammals run into problems at weaning.