Whales too Get 'Suntanned' : Study

Like humans, some species of whales also get suntans, according to a latest discovery.

An international team of experts from Newcastle University along with colleagues in Canada and Mexico have discovered that some species of whales get darker with sun exposure and their skin suffers damage similar to humans as they get older.

Prior to this, a study published in the Proceedings of the Royal Society B revealed that whales exhibit skin damage akin to the acute sunburns in humans.

"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," said Karina Acevedo-Whitehouse, currently Senior Lecturer at the Universidad Autónoma de Querétaro, Mexico.

The marine biologists in Mexico called the skin experts from Newcastle University after they saw a growing number of whales in that area developing blisters on their skins.  They worked on the skin samples of three types of whales; the blue, sperm and fin whales. Over three years the experts collected skin samples from  the three species during their annual migration between February-April to the sunnier Gulf of California.

Compared to the sperm whales that had a darker pigmentation, the jumbo sized blue whales had very pale pigmentation. There was a seasonal change in the skin pigmentation in the blue whale as well as DNA damage.  Similar to the sunburned human skin, the UV exposure caused internal damage to the mitochondria.

Sperm whales spend a longer time on the surface between feeds due to which their exposure to sun and UV is more resulting in a darker pigmentation. These sperm whales trigger a stress response in their gene in order to protect themselves from the sun.

"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," said Newcastle University researcher Amy Bowman.

The darkest whale, the fin whale , was found to be resistant to the damage of the sun and had less sunburn injuries on their skin.

The researchers are further studying whether this UV damage develops into skin cancer and if the burns are an early warning system.

The study is published in the journal Scientific Reports.