Monk Seal Monday #32: Molting

About the first of the month, two-year-old RH92 was reported to have started her annual molt. She joins four other seals known to have molted this year thus far: R1KT, R3CX, RG22, and V2.

Photo credit: Lynn Nowatzki

Hawaiian monk seals experience what’s called a “catastrophic molt,” meaning the loss of the top layer of skin and fur happens in one concentrated period of time, rather than continually throughout the year. The molting process can take one to two weeks. Because molting requires great energetic resources, during this time, the seal will usually stick pretty close to the beach, often spending the night tucked high up the beach and under bushes.

Molting is a vulnerable time for monk seals, another reason to encourage folks to keep dogs on leashes. Typically, the molt starts on the belly, flippers, muzzle, and scars. Then, moves to the back. The molting pattern isn’t exactly “attractive.” A seal with patches of dead skin falling off can often cause beach-goers concern, thinking the seal is sick or, even, dead.

Adult females will often molt soon after they wean their pups. Also, any seals outfitted with a telemetry tag near its molt will lose it during the molt. (If you happen upon a telemetry tag on the beach–it’s a rare event but it has happened–please call the monk seal hotline to report it.)

Photo credit: D. Lee

Basically, seals molt, because their coat gets dirty. After spending long bouts of time at sea, algae will often grow on their fur. If you see a seemingly green-colored seal, you’ll know he or she is nearing his/her molt.

After molting, monk seals regain their dark gray to brown color on their dorsal (back) side and a light gray to yellowish brown color on their under (ventral) side. This difference in coloration is known as “countershading.” From below, the seal’s light belly blends in with the sunny surface of the ocean. From above, the seal’s darker back is closer in color to the dark ocean floor. This serves as camouflage for seals. It helps them sneak up on prey, as well as, hide from sharks and other predators.

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Field Report: May 2018

Sightings:

The Kauai team logged 33 individually identified monk seals on Kauai in May, for a grand total of 332 sightings. This equates to more than 10 monk seals sighted and reported per day.

New:

• Juvenile female R7AA hauled out onto roads or parking lots three times in the Poipu area this past month. In order to prevent injury from vehicle traffic she was quickly displaced back onto the beach and into the water.
• We are currently tracking several pregnant females that we expect to pup any day now. That includes the well known RK30 and a more reclusive seal RK22. Two other females, RH58 and RO28, that are typically on Oahu but come back to their birth beaches on Kauai to pup, are both pregnant and approaching their due dates.

Updates:

• RK13 gave birth to PK1 on 4/20/2018. Extensive monitoring was immediately set-up and continues. Pup weaned after 37 days of nursing. Tagged as RK42. Mother, RK13, became unusually thin prior to weaning, but has been sighted several times since weaning. The pup has begun socializing with other seals, specifically with a 3-year old female bleach-marked V2.

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