A uncommon, vividly orange nurse shark has been found off the coast of Costa Rica, baffling scientists and prompting renewed curiosity in marine pigmentation anomalies.
The six-foot-long shark was caught throughout a sport fishing journey close to Tortuguero Nationwide Park, at a depth of 37 metres. In contrast to the standard brown colouring that nurse sharks use for camouflage alongside the ocean ground, this shark’s vibrant orange hue made it stand out starkly in opposition to its environment.
In line with researchers from the Federal College of Rio Grande, this peculiar colouration is because of xanthism—also called xanthochroism—a uncommon situation of pigmentation. “Additional analysis is required to discover potential genetic or environmental components influencing this uncommon pigmentation anomaly in sharks,” the researchers famous, based on The Unbiased.
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Xanthism causes extreme yellow or golden hues on account of an absence of pink pigmentation. It has by no means been documented earlier than in cartilaginous fish, the group of species that features sharks, rays, and skates, within the Caribbean.
Scientists in ‘Costa Rica’ found the primary nurse shark with each albinism & shiny yellow xanthism 🌊🦈 Uncommon combo challenges survival assumptions and offers new insights into shark genetics. pic.twitter.com/iLHVvlO0XD
— PastToFuture 🕰️➡️🤖 (@PastTo_Future) August 20, 2025
Along with its golden-orange pores and skin, the nurse shark additionally confirmed indicators of albinism, significantly a pair of hanging white eyes. These bodily traits may make it extra weak within the wild. Usually, nurse sharks depend on their brown pores and skin to mix into the seabed. Vibrant colouring and white eyes take away that pure defence.
Nonetheless, the presence of each xanthism and albinism traits raises attention-grabbing organic questions. Whereas some scientists consider that animals with xanthism are at a survival drawback on account of their visibility to predators, this discovery challenges that idea.
The origin of the pigmentation continues to be unsure. Whereas xanthism is commonly the results of a genetic mutation, environmental components comparable to weight loss program may additionally play a task. Researchers consider this discovering may result in broader questions concerning the genetic variety of native nurse shark populations. The complete examine was printed within the journal Marine Biodiversity.
Xanthism is taken into account extraordinarily uncommon throughout the animal kingdom. It’s beforehand been noticed in a small variety of fish, reptiles, and birds. As an illustration, vivid yellow morphs have appeared in freshwater fish, whereas parrots and canaries have been seen with golden feathers. Occasional experiences have additionally emerged of yellow snakes and lizards exhibiting the situation.
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On the alternative finish of the pigmentation spectrum is axanthism, a situation marked by an absence of yellow pigment.
