Hi Michael – Squirrels are eutherian mammals, meaning they bear live young which are nourished in utero through a placenta.
The umbilical cord transports the fetal blood to the placenta, where it is nourished with oxygen and nutrients from the mother’s circulation. After birth, the remnant of the umbilical cord connection is the belly button, or umbilicus. Squirrels thus have a belly button.
Mammals also nurse their young through mammary glands which produce the milk. The milk in eutherian mammals is exuded through the nipples. Squirrels, being eutherian mammals, thus have nipples.
- Lynn Bry, MD/PhD, Dept. Pathology, Brigham & Women’s Hospital, Harvard Medical School
Interestingly it would seem that Gerry had a similar question about dogs and cats having belly buttons.
Thanks Mad Science Network!
Additionally, The Worldwide Wildlife Fund has written me indicating that they have printed out Squorty Tails, the Delmarva Fox Squirrel, and hung him on their bulletin board. And if you ask me, that is almost as good as getting published!