Whales that acquire suntans as they migrate to sunnier spots are being studied by North East experts.
The whales can act as “barometers” of the health of the oceans, the impact of climate change and also link in with research on skin damage from the sun in humans.
Whales have been shown to increase the pigment in their skin in response to sunshine – just as when people develop a tan.
Research published today reveals that not only do some species of whales get darker with sun exposure – incurring DNA damage in their skin just like humans – they also accumulate damage to the cells in the skin as they get older.
Experts in the response of skin to UV radiation at Newcastle University were called in after marine biologists in Mexico noticed an increasing number of whales in the area had blistered skin. Analysing samples from three types of whales – blue, sperm and fin – they worked together to study the changes in the whale skin after their annual migration to sunnier climes.
Mark Birch-Machin, Professor of Molecular Dermatology at Newcastle University and joint senior author of the research paper said: “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.”
Over three years, marine biologists took skin samples from the backs of three species of whales during their annual migration, when between February and April the whales move to the sunnier Gulf of California, along the northwest coast of Mexico.
Blue whales, the jumbo-jet sized giants, have a very pale pigmentation. During migration time, the team found a seasonal change with the pigment in their skin increasing as well as DNA damage. This internal damage to the mitochondria, the engines of the cells, is caused by UV exposure and is what is found in sunburned human skin.
Sperm whales with their distinctive rounded foreheads have a darker pigmentation and also migrate between February and April to the Gulf of California, but have a different lifestyle. They spend long periods at the surface between feeds and are therefore, exposed to more sun and UV.
The scientists found the sperm whales had a different mechanism for protecting themselves from the sun, triggering a stress response in their genes. Newcastle University researcher Amy Bowman said that the studies showed for the first time evidence of pathways being activated in the cells of the whales similar to the damage response caused in human skin.
In contrast, the darkest whales, the deeply pigmented fin whales, were found to be resistant to sun damage showing the lowest prevalence of sunburn lesions in their skin.
“We need to investigate further what is happening,” said Prof 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 of skin damage.
“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. They are a reminder that changing climatic conditions are affecting every creature on the planet.”
Prof Birch-Machin said that the whale study could also link to skin damage and ageing in humans from sun exposure.