It’s the Monday after Thanksgiving, and there’s probably a few of us who could shed a few pounds after feasting all weekend, so let’s talk about molting.
Healthy Hawaiian monk seals molt once a year. That is, they shed the top layer of their skin–and their fur along with it. It’s called a “catastrophic” molt, because it happens over a shortened period of time of about 10 days to two weeks. Unlike a snake, say, the process doesn’t happen all in one piece but in bits and pieces. A monk seal can look pretty raggedy during this time. The molting process taxes the monk seal’s energetic resources, so you’ll often find a molting animal tucked under bushes and resting on the beach. That’s all the more reason to not disturb them and why the HMSRP rarely uses them as study subjects–say for telemetry and/or video camera purposes.
We’ve got a couple Hawaiian monk seals going through their annual catastrophic molts right now and a few more ready to start any time, including RH80, RH38, and, possibly, RK14.
The clue to knowing when a monk seal is about to molt is when they start looking very green. Monk seals tend to spend two-thirds of their life in the water. During that time, algae can grow on their fur, typically in areas where a monk seal’s fur doesn’t always dry out–under the fore flipper and around their rear flippers.

Photo credit: Lynn Nowatzki