16 October 2022

Dolphins have specialized skin for their underwater lives. The outer layer (epidermis) feels rubbery and is 15 to 20 times thicker than our own. It stays smooth because:

Dolphin skin constantly flakes and peels as new skin cells replace old cells. A bottlenose dolphin’s outermost skin layer may be replaced every 2 hours. This sloughing rate is 9 times faster than in humans. This turnover rate ensures a smooth body surface and probably helps increase swimming efficiency by reducing drag (resistance to movement).

— Seaworld.org: Bottlenose dolphin characteristics

Dolphins will even take turns to rub their bodies on corals and sponges, an activity that probably feels good. (video: Why Taking Turns Is Good for Dolphin Skin)

We know these things about dolphins because some have a close association with humans. Veterinarians and trainers take an active interest in the welfare of animals in their care.

Dolphin veterinarians are especially concerned that as dolphins age, their heart health may suffer. This includes the dolphins in the U.S. Navy’s Marine Mammal Program in San Diego.

Last year the Navy asked for proposals to place heart monitors on their aging dolphins to unobtrusively monitor them as they move about in the ocean. There are many challenges to doing so including the dolphins’ skin. Because the skin turns over every two hours nothing can stick to it for long. I wouldn’t know about their skin if I hadn’t heard about the heart monitors.

The vast majority of us rarely if ever seen dolphins in the wild and know very little about their lives. We are mesmerized when we see them this close.

It’s hard not to love them.

(photos from Wikimedia Commons and from Royal Society Publishing; click on the captions to see the originals)