Whales Migrate to Shed the Skin They’re In


By Ralph Birch

Without access to the latest human moisturizers and rejuvenation regimens, whales are resorting to relocation as a means for maintaining healthy skin.

Scientists have discovered that certain whale species are migrating to warmer waters to rid themselves of their bacteria-laden outer layers.

Robert Pitman, a marine ecologist at Oregon State University’s Marine Mammals Institute, attached satellite tags to four different species of whales that inhabit Antarctic waters.

Pitman tracked the whales over eight southern summers and found that both baleen and toothed whales traveled as many as 9,400 kilometers to the western part of the South Atlantic Ocean. However, they don’t make the trip to give birth in warmer waters or escape their typical predators.

Researchers are aware that whales, like humans, shed skin cells continuously. But whales are unable to molt in the cold waters of the Antarctic. Instead, they build up a thick, yellow film of microscopic diatoms on their skin.

High concentrations of diatoms can result in the accumulation of harmful bacteria on the skin, which can have an adverse effect on the health of both killer and baleen whales.

The observation of the yellow buildup on the skin of killer whales led researchers to take a closer look. To help them conserve heat in colder waters, researchers hypothesized that killer whales divert blood flow away from their skin.

This causes skin cell regeneration to slow down and drives the whales to seek out warmer waters where their metabolism — and presumably their ability to molt — increases. A recent report published in Marine Mammal Science supports Pitman’s assertions, concluding that all whales, not just certain species, migrate for the purpose of molting.

Scientists consider this explanation to be plausible for killer whales, but they’re doubtful this pattern of behavior can be applied to all whale species. Richard Connor,  a cetacean biologist at the University of Massachusetts-Dartmouth, points out that newborn baleen calves are incredibly vulnerable to predatory killer whales.

“The cost of being eaten is much higher than the cost of molting in cooler waters,” Connor said.

Pitman stands by his findings, pointing out that the effects of whale molting on ocean ecosystems is deserving of further study.

“Most people don’t consider skin molt important to whales,” Pitman said. “But it’s an important physiological need. Shedding their skin is a first-line defense against disease and bacteria.”

Discussion Questions

  • Can you think of any other reasons why whales migrate?
  • What effects do you think whales’ molted skin cells have on other marine life?


  • baleen
  • molt
  • diatom
  • cetacean