Why is this manta ray pink?

Spotted recently off the Great Barrier Reef, the little-seen manta ray’s rosy hue is not due to infection or diet scientists say, according to National Geographic.

Photographer Kristian Laine was freediving recently off the southernmost island of Australia’s Great Barrier Reef when a bright pink manta ray glided by. He thought for sure that his camera was malfunctioning.

“I had no idea there were pink mantas in the world, so I was confused and thought my strobes were broken or doing something weird,” says Laine. He later realized he’d spotted an 11-foot male reef manta ray named after Inspector Clouseau, the bumbling detective of the Pink Panther movies. The fish, who cruises the waters around Lady Elliot Island, is the only known pink manta ray in the world.

First spotted in 2015, Inspector Clouseau has been seen fewer than 10 times since. “I feel humbled and extremely lucky,” says Laine, who photographed him amid a group of seven other males, all of them vying for a female. 

Scientists with the Australian research group Project Manta, who study the rosy ray, have confirmed its colour to be real. At first, they theorised Inspector Clouseau’s colour was the result of a skin infection or diet, similar to how pink flamingos get their colour from eating tiny crustaceans. But in 2016, a Project Manta researcher took a small skin biopsy from the famous animal, and the resulting analyses ruled out diet and infection as the cause.

Now, according to National Geographic, Project Manta’s leading theory is that the manta has a genetic mutation in its expression of melanin, or pigment, says Asia Armstrong, a research assistant for the group.

And the ray is not just a cool-looking animal—it could contribute to science, she adds by email. “Understanding the origin of this genetic mutation may help inform us about how colour evolved in mantas,” she says.

Solomon David, an aquatic ecologist at Louisiana’s Nicholls State University, suspects the mutation is a condition called erythrism, which causes an animal’s skin pigmentation to be reddish, or in some cases, pink. Other more well-known genetic mutations to an animal’s pigment can make them melanistic (black) or albino (white).

“Having seen other pigmentation-related mutations in fishes, it’s not completely unexpected that this exists, but it’s really cool to see regardless,” Solomon says.

Guy Stevens, CEO and co-founder of the U.K.-based Manta Trust, agrees that erythrism is the most plausible explanation.

Stevens doesn’t think the manta’s atypical colour will impact its survival or vulnerability to predation. That’s mostly because of the reef manta’s massive size; an adult can easily weigh more than a ton. 

“They are big when they are born, and they grow quite quickly in their first few years to make them large enough that only the biggest of marine predators prey on them. It just goes to show—nature will always surprise you,” he adds. “Now the search is on for a blue manta.”