Fishers caught a bright orange shark off Costa Rica that had albinism, alongside the species’ first scientifically documented case of an extremely rare condition called xanthism.
Rare Bright Orange Nurse Shark Spotted in the Caribbean: A First-of-Its-Kind Discovery
In a stunning discovery off the east coast of Costa Rica, researchers have documented a bright orange nurse shark exhibiting a rare condition called xanthism — marking the first confirmed case in this species.
The 6.6-foot (2-meter) shark was spotted by sports fishers in 2024 near Parismina, swimming 120 feet (37 meters) below the surface. Its vivid orange coloration and white eyes immediately caught attention.
“We could not believe what we had in front of our eyes,” said Garvin Watson, owner of the Parismina Domus Dei hotel. “That orange shark shining with the sunlight was something out of the ordinary.”
The fishers safely photographed the shark, removed the hook from its mouth, and released it back into the Caribbean Sea.
What is Xanthism?
Xanthism, also known as xanthochroism, is a genetic condition that increases yellow pigmentation in the skin, sometimes producing bright orange or golden hues. While the phenomenon has been observed in frogs, birds, and fish, it had never been scientifically documented in nurse sharks (Ginglymostoma cirratum) — until now.
Interestingly, researchers also noted signs of albinism in the shark, including the absence of black pigmentation in its irises. This combination, known as albino-xanthochromism, has previously been seen in a few rays but is extremely rare in sharks.
“We were very surprised and excited when we saw the [xanthism] in the photos,” said study lead author Marioxis Macías-Cuyare, a doctoral candidate in biological oceanography at the Federal University of Rio Grande in Brazil.
How Rare is This Coloring?
Nurse sharks typically range from yellow to gray-brown, blending into their environments to avoid predators. Bright orange coloring would normally be a disadvantage in the wild, making this shark’s survival into adulthood particularly remarkable.
“Many factors influence this, such as the environment, but everything remains speculative until the variables that could influence this genetic condition are tested,” Macías-Cuyare explained.
The causes of abnormal pigmentation in sharks are still being studied. Genetics plays a primary role, but environmental factors such as stress, water temperature, and hormonal imbalances may also contribute.
Why This Discovery Matters
This finding provides a unique opportunity for scientists to study shark genetics and pigmentation, as well as the ecological impacts of unusual coloration in marine animals. The shark’s successful survival despite its bright orange hue may offer insights into how rare genetic variations can persist in wild populations.
The study detailing this discovery was published on August 1 in Marine Biodiversity, highlighting the importance of documenting rare marine anomalies and the resilience of wildlife in their natural habitats.
Final Thoughts
The orange nurse shark with white eyes is more than just a curiosity — it’s a living testament to the incredible diversity of life in the ocean and the ongoing mysteries waiting to be uncovered beneath the waves.
“We did not know that it was going to be a discovery worldwide, recognized by all the biologists of the world,” Watson said.
This extraordinary sighting is a reminder that even well-known species can surprise us — and that careful observation and conservation are essential for understanding the natural world.