#SharkÂ
Fishermen caught a bright orange shark near Costa Rica that had albinism, along with the first scientifically documented case of an extremely rare condition called xanthism in this species
A bright orange shark with white eyes, one of a kind, was caught and released in the Caribbean, a new study reveals.
The nurse shark (Ginglymostoma cirratum) had a mysterious condition called xanthism, or xanthochroism, which increases yellow pigmentation in the skin.
Researchers have recorded xanthism in several animals, but this is the first confirmed case of a nurse shark with this characteristic.
The shark also appears to have albinism, making it even more special and unusual.
Sport fishermen stumbled upon the shark off the east coast of Costa Rica in 2024. Garvin Watson, owner of the Parismina Domus Dei hotel in the village of Parismina, hooked the animal, which measured about 2 meters long and was swimming at a depth of 37 meters.
“We couldn’t believe what we were seeing,” Watson told Live Science via email.
“That orange shark glowing in the sun was something out of the ordinary,” he said.
“We didn’t know it was going to be a global discovery, recognized by every biologist in the world.”
The fishermen took photos of the shark, removed the hook from its mouth, and released it back into the Caribbean Sea.
Scientists described the case and its significance in a new study published August 1 in the journal *Marine Biodiversity*.
Scientists have previously documented xanthism in several species, including frogs, birds, and fish.
While some animals are naturally yellow or orange, in these xanthic creatures, these colors are even more intense.
Nurse sharks are typically yellow to grayish-brown in color.
There have been sporadic reports of strange colorations in this species, including albinism-a complete lack of melanin (the pigment that gives color to skin and eyes)-and possible cases of xanthism, but a xanthic nurse shark had never been scientifically documented before, according to the study.
“We were very surprised and excited when we saw [xanthism] in the photos,” the study’s lead author, Marioxis MacÃas-Cuyare, a doctoral candidate in biological oceanography at the Federal University of Rio Grande do Sul in Brazil, told Live Science via email.
The researchers spoke with Watson and analyzed the shark’s photos.
They noted that the animal lacked the black irises typical of shark eyes and concluded that it was likely albino in addition to being xanthic.
A 2018 study recorded this combination of conditions, called albino-xanthochroism, in a species of stingray (Raja montagui) found in the Irish Sea.
Scientists are still studying the causes of abnormal pigmentation in sharks.
These conditions are often linked to genetics, but factors such as environmental stress, higher temperatures, and hormonal imbalances can also contribute to different colors, according to the study.
MacÃas-Cuyare said xanthochroism is usually genetic, but more research is needed to understand what influenced this shark’s unusual pigmentation.
The shark’s survival is also curious.
Animals evolve to have specific colors that help them survive in their environment, so being bright orange-when the species isn’t designed for it-would normally be a problem.
In this case, the shark reached adulthood and doesn’t appear to have been harmed by the unusual color.
“Many factors influence this, such as the environment, but everything remains speculative until the variables that may affect this genetic condition are tested,” said MacÃas-Cuyare.
Published in 09/13/2025 07h06
Text adapted by AI (Grok) and translated via Google API in the English version. Images from public image libraries or credits in the caption. Information about DOI, author and institution can be found in the body of the article.
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