A few weeks ago, we posted a birth announcement for Galinda. Four of her pups had made it past the critical first five days of life, and were on track toward growing up healthy and strong. Now five weeks old, they are still doing well, and we have some further news to share.
As long time fans of our naked mole-rat colony are aware, we are in the very unusual position of having two reproductive females. While not unknown, this situation usually resolves through fighting, but in our case seems to have become a stable long term configuration.
It was still a surprise to see a visibly pregnant Elphaba nursing some of Galinda’s pups, as Brianna observed on June 16. This was the first time we have ever observed pups nursing, with seeming success, on an individual other than their mom. Although the mammary glands of all naked mole-rats become well developed near the end of the queen’s pregnancy, we could find no reports of actual milk being produced, let alone of animals providing milk for pups other than their own. Elphaba appears to be doing something never before seen.
Nursing from two females is clearly beneficial for the pups. They gain extra nutrition, and create a social bond with Elphaba while still having the milk and attention of their own mother.
It is a little more puzzling what Elphaba gains. On the face of it, in fact, she appears to be losing nutrients and possibly risking her own litter. Nursing can cause the release of oxytocin, a powerful hormone related to childbirth and parent/infant bonding. Nursing another animals’ pups could lead to her pups being born prematurely, and it certainly is taking resources she would normally be giving to her own offspring. At this point we do not have a clear understanding of why this nursing took place, though it is certainly interesting to observe and speculate.
What is clear is that nursing another female’s babies did not prevent Elphaba from producing at least some viable pups. She gave birth on the June 17th. Two of the pups from that litter survived the critical 5-day mark and have past day ten. From all appearances, they are growing and developing right on track!
