Callosities: blemishes or beauty marks?

North Atlantic right whale with callosities displayed

North Atlantic right whale with callosities displayed

Callosities (from the word callus)  are natural skin bumps found on the head of right whales. Most of the time it’s pretty tough to see these bumps because they are usually surrounded by whale lice. But if you look really closely at the photo you can see the dark gray bumps sticking up through the whitish orange lice army.

When right whales are born, there’s an area of smooth light gray skin that quickly acquires the bumpy look. Scientists aren’t sure why these callosities form or what purpose they serve. According to the Encyclopedia of Marine Mammals: “Male southern and northern right whales have, on average, a greater portion of the surface area of their head covered by callosity tissue than do females.”

The author of the encyclopedia article suggests that callosities play a role in mating competition. Males could use these more plentiful bumps to scratch each other when vying for a mate. My guess is that the ladies are into these callosities and the more a whale has, the more manly he is. So it could be that these blemishes are really beauty marks. As they say, it’s all in the eye of the beholder.


  1. J Napoli says

    It sounds like callosites are very mysterious creatures, very Zen-like, plus they spend most of their time surrounded by whale lice, which we assume takes a lot of fortitude.

  2. Bryan says

    I may be part right whale. I know my callosites came in handy when I was vying for the affections of a certain wild life blogger.

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