The way that whales react to sunlight can shed new light on the human ageing process, say researchers.
Some species react by getting darker with UV exposure in the same way as humans get a tan.
Others though, protect from themselves from sun burn by turning genes on and off.
The work, which is published in the journal Scientific Reports, could lead to new anti-ageing treatments in humans.
For several years now, marine biologists in Mexico have noticed an increasing number of whales in the region with blistered skin as a result of exposure to UV light.
Over a three-year period researchers took skin samples from three different species of whales during their annual spring migration, when they move to the sunnier waters of the Gulf of California.