Anyone who has experienced the searing pain of sunburn knows that too much sun can wreak havoc on your skin.
Turns out that our fellow mammal, the whale, can also tan and get sunburn.
Research by an international team of scientists showed that, not only do some species of whales get dark tans when they’re exposed to the sun, but they also suffer harm to their skin’s DNA. And just like us, whales can wind up with damaged skin cells as they get older.
Marine biologists at Universities in Mexico noticed that an increasing number of whales in their area had blistered skin, so they called in researchers from the UK’s Newcastle University. The British scientists analyzed skin samples from three types of whales, the blue whale, sperm and fin whale.
They worked with their Mexican colleagues along with other marine biologists from Canada’s Trent University, to study changes in whale skin after the gargantuan creatures made their annual migration to sunnier climes.
“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, a senior author of the study and a professor of molecular dermatology at Newcastle University.
The Mexican and Canadian scientists took skin samples off the backs of the three species of whales over a three-year period between February and April, when the whales make their annual move to the sunny Gulf of California, located along the northwest coast of Mexico.
The biggest species the researchers studied was the pale-skinned blue whale.
The team found a seasonal change with the blue whale during its migration time. They noticed that the whale’s skin pigment increased and that its skin cell’s mitochondria – a cell’s power plant – were also experiencing some DNA damage. They say that the internal mitochondrial damage that was discovered was caused by UV exposure and was similar to what could be found in the sunburned human skin.
Another species, sperm whales have a darker pigmentation than their blue whale relatives. While they too take part in the annual February to April trek to the Gulf of California, the sperm whales have a different lifestyle than other whales. They spend a long time on the water’s surface which means they are exposed to more UV rays.
But the researchers found that by setting off a stress response in their genes, the sperm whales had developed a unique mechanism to protect themselves from harm caused by the sun.
“We saw for the first time evidence of genotoxic (a toxic agent that damages DNA molecules in genes) 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 Amy Bowman, a researcher from Newcastle University.
The third species studied by the researchers was the fin whale, which compared to the blue and sperm whales, had the deepest pigmented skin. Because of their darker skin color, the researchers discovered the fin whale had the lowest number of sunburn lesions on their skin, which meant that they were more resistant to sun damage.
“We need to investigate further what is happening,” said 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 research team noted that their findings serve as a reminder that changing climatic conditions are affecting every creature on the planet.