Some Species of Whales Get Tans, Sunburns

Just like humans, whales also get a tan, a new study has found.

Researchers from Newcastle University and their colleagues in Canada and Mexico have found that some species of whales not only get darker when exposed to sunlight, but they also accumulate DNA damage in cells as they get older.

Back in 2010, another team of researchers from Zoological Society of London too had found that whales in California are displaying signs of sunburns. Scientists then said that factors such as ozone depletion, increased UV exposure were increasing risk of skin blisters in whales.

According to experts, whales can be a good indicator of the ocean's health.

"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," said Mark Birch-Machin, Professor of Molecular Dermatology at Newcastle University and joint senior author of the paper.

Marine biologists called in skin experts from University of Newcastle when they started noticing burns and blisters on some whales. Close examination of skin samples of three types of whales - blue, sperm and fin showed changes in appearance after annual migration to sunnier regions.

Each year between February and April, whales migrate to Gulf of California along the northwest coast of Mexico.

Researchers studied the whales for over three years and found that blue whales tend to get darker skin along with damage to the mitochondria each summer. The skin damage was similar to sunburnt skin of humans.

Sperm whales have a slightly darker skin color when compared with blue whales. The scientists found that exposure to sun led to stress response in genes of sperm whales.

"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 from Newcastle University said in a news release.

Fin whales that have the darkest skin of the three species experienced very little skin damage.

There have been many reports of whales having burns and blisters on their skin. Researchers said that understanding the mechanism of these blisters is important to learn aspects of evolution in the species and design methods to protect whales from further sun damage.

"We need to investigate further what is happening," said Professor Birch-Machin, "if we are already seeing blistered skin in the whales caused by UV damage then we want to know whether this could develop into skin cancer and therefore serve as an early warning system.

The study is published in the journal Scientific Reports.