You won't see a whale slathering on the tanning oil anytime soon, but that doesn't mean their skin doesn't respond to the Sun.
Pigment in whales' skin changes when exposed to sunlight, similar to the way a human's would when getting a tan, a Newcastle University press release reported.
Researchers first noticed this phenomenon after observing several whales with "blistering skin." In the study, they found the aquatic mammals can get DNA damage from the Sun, just like humans. They also "accumulate damage" in their skin cells as they age.
"Whales can be thought of as the UV barometers of the sea. It's important that we study them as they are some of the longest living sea creatures and are sensitive to changes in their environment so they reflect the health of the ocean," co-author of the paper Mark Birch-Machin, a professor of Molecular Dermatology at Newcastle University, said.
The research team took samples of the back skin of blue, fin, and sperm whales during their annual migration.
Blue whales have very light skin, so researchers noticed "a seasonal change with the pigment in their skin increasing as well as mitochondrial DNA damage." This is similar to what is seen in sunburnt human skin.
Sperm whales have darker skin, but spend more time at the top of the water and endure more exposure to UV light. They found the round-headed whales had a genetic defense against the harmful rays.
"We saw for the first time evidence of genotoxic pathways being activated in the cells of the whales - this is similar to the damage response caused by free radicals in human skin which is our protective mechanism against sun damage,"Amy Bowman, a Newcastle researcher said.
Fin whales have very dark, highly pigmented skin; they showed a strong resistance to the Sun's rays.
"There has been an increase in the number of reports on blister-type skin lesions in various whale species in areas of high UV radiation. In many cases no infectious microorganism has been found associated with these lesions. It's important that we study the effect of UV radiation on whale skin and the mechanisms that these species use to counteract such damage, both from an evolutionary approach and from a conservation perspective," Karina Acevedo-Whitehouse, Senior Lecturer at the Universidad Autónoma de Querétaro, said.
Acevedo-Whitehouse warned further study is essential in monitoring the effect of climate change on the blistering whales. Researchers should also observe if these blisters are early signs of skin cancer.
