This Orange Shark Is the Result of a Rare Genetic Double Whammy

The depths of the Caribbean host a spectacular array of marine life—including this nurse shark featuring vivid orange scales and cloudy white eyes.

Last year, anglers on a fishing trip near Costa Rica with Parisima Domus Dei, a tourist company, reeled in what looked like a giant goldfish with shark-like chompers. After snapping some photos of the creature—about 6 feet (1.8 meters)—the fishermen let it go, later describing their strange encounter to marine experts. 

The researchers concluded that this odd creature was not a bloated goldfish. Rather, it was a nurse shark (Ginglymostoma cirratum), a well-known predator living in Caribbean waters. But unlike most of its brethren, this orange nurse shark has not one but two extremely rare conditions—xanthism and albinism, a combination only observed once before in marine creatures. A detailed account of the orange nurse shark’s discovery and analysis was published earlier this month in Marine Biodiversity.

Is this shark okay?

Yes. At least, the data we do have about the shark doesn’t seem to imply that it’s suffering from major health issues. For researchers, this orange shark is a living example of nature’s wonders—and quirks. Xanthism, or unusually yellow pigmentation, is so rare that it’s only been recorded a handful of times across all animal species. That alone makes this orange shark special, but it also had “white eyes, with no visible iris,” implying the shark has albino-xanthrochromism, the mix of the two rare conditions. 

Meanwhile, nurse sharks are normally brown, an unassuming color that helps the predator blend into its surroundings. What’s remarkable about the orange shark is that it survived to adulthood without such camouflage—a promising sign for its survivability, according to the paper. 

But the genetic pathway that resulted in this aesthetic is still unclear. Independently, albinism and xanthism are associated with genetic mutations. However, researchers are wondering if this unique mix could have emerged from inbreeding or environmental stresses, such as elevated sea temperatures or hormonal imbalances. The discovery “raises important questions about the genetic variability and adaptability of nurse sharks in specific habitats,” the paper noted.

Whenever I learn about strange animal mutations, my first thought—or concern, rather—is whether we humans exposed them to some horrible pollutant that’ll eventually end with their untimely death. So far, it doesn’t seem like that’s the case for this orange shark, which is great news.