Q: My ten-year-old daughter recently asked me a very good question — and I didn’t know how to answer her. While playing with our male cat, Henry, she rubbed his belly and discovered that he has nipples. She wants to know the purpose of them. And quite frankly, so do I. Hopefully, you can help!
A:Dear Elizabeth: When babies are first developing inside their mother, they look pretty much the same. Both males and females have nipples at birth, but only the female will ultimately use them to nurse young. At a later age, the female produces special hormones (estrogen, progesterone) that allow gland development and the ability to produce milk.
According to the Darwinian theory of evolution, there simply wasn’t a survival advantage for males to stop having nipples. So both males and females have nipples at birth, but only the female will ultimately use them to rear her young.
Michael Stone, DVM
Clinical Assistant Professor
Cummings School of Veterinary Medicine at Tufts University