The bright orange nurse shark was caught and released in Costa Rica. Photo: Facebook//Parismina Domus Dei
When you think of the color of a shark, you think grey. That’s because, for the most part, they are grey. Some, of course, vary in coloration, but bright orange is not a normal hue for a shark. Nature is wild, though, and a nurse shark was caught off Tortuguero National Park in Costa Rica last year that shucked off the bland, normal hues of its species.
“The adult shark, approximately 200 cm in total length, exhibited intense yellow-orange pigmentation and white eyes, indicating a condition known as albino-xanthochromism,” wrote researchers in a paper for Springer Nature.
The shark was caught by a fisherman named Juan Pablo during a sport fishing trip. It had a condition called xanthism, which is extraordinarily rare in marine species. So rare, in fact, that it has not ever been previously reported in cartilaginous fish in the Caribbean. Color is important in the animal world, as it’s often used to disguise the creature in its surroundings. Nurse sharks — not to be confused with the grey nurse shark, a different species — generally come in a muted brown-ish color, but this one was decidedly not muted.
According to IFLScience, xanthochromism is a genetic condition that “causes an excess of yellow-orange tones in the skin, hair, or fur of animals.” It’s generally assumed that it would be weaned out of the population because it makes survival tougher, but this one defied expectations.
“This unique finding suggests that xanthism does not hinder survival in this species,” reads the paper’s abstract.
Although it is assumed that the xanthism is genetic, there are other things that could be at play in this case. “Factors such as inbreeding, environmental stress, elevated temperatures, and hormonal imbalances may also influence pigmentation,” they explained.
The photos were recently shared on a Facebook page run by Parismina Domus Dei, a tourist information center in Costa Rica. “The vastness of the ocean amazes us every day!” its administrators wrote.
