August 30, 2013
Can Whales Get Sunburns?
[ Watch the Video: Whales Can Get A Tan Like Humans ]
Brett Smith for redOrbit.com - Your Universe Online
If you spent the whole day swimming in the ocean you might expect to get a tan, and a new study has found that whales also experience an increase in skin pigment as a result of exposure to the sun’s rays. The same study also found that the skin of blue, sperm and fin whales can suffer genetic damage due to UV ray exposure – just like humans.
According to a recently published article in Scientific Reports, researchers from Newcastle University in the UK and other institutions made the discovery after marine biologists in Mexico spotted a growing number of whales with blistered skin. Samples were taken from the three types of whales to study how their skin is affected by the annual migration to sunnier waters.
"Whales can be thought of as the UV barometers of the sea,” said Mark Birch-Machin, a molecular dermatologist at Newcastle University. “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."
Over the course of three years, marine biologists took skin samples between February and April, when the whales migrate to the Gulf of California. Skin cells from these samples were analyzed for their genetic response to UV rays.
Each species of whale was found to react differently to light. With their pale pigmentation, blue whales exhibited a seasonal increase in the pigment of their skin as well as mitochondrial DNA damage caused by UV exposure.
Sperm whales have a darker pigmentation as well as a different lifestyle. They tend to spend long periods at the surface of the ocean, exposing themselves to more sun and UV radiation. The team found that sperm whales are able to trigger a stress response in their genes 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 co-author Amy Bowman, a researcher at Newcastle University.
The darkest of the three species, fin whales were found to be resistant to sun damage, exhibiting the least amount of sunburn lesions in their skin.
"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,” said co-author Karina Acevedo-Whitehouse, currently a lecturer at the Universidad Autónoma de Querétaro, Mexico. “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,” she added in a statement.
The study also marks the first time migratory patterns have been linked to genetic damage.
"We need to investigate further what is happening," Birch-Machin said, "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."
"These whales occupy the same area year after year, so it is increasingly possible to understand the status of their populations, and what may be going on around them and in the environment,” he added. “They are a reminder that changing climatic conditions are affecting every creature on the planet."