In August 2024, a group of anglers off the coast of Costa Rica’s Tortuguero National Park experienced something they would never forget. As they reeled in their catch from about 37 meters below the surface, a flash of color unlike anything seen before in these waters emerged. Instead of the familiar gray or brown tones of a nurse shark, a glowing orange predator with eerie white eyes came into view.
The shark was about six feet long, its body shining with an intense yellow-orange hue that stood out vividly against the blue-green waters. Even more striking were its eyes — pale white, with no visible irises, giving the shark an almost ghostlike appearance.
The anglers, shocked and amazed, took photographs before carefully releasing the animal back into the ocean. Those pictures were later shared by Parismina Domus Dei, a local tourist company, and eventually caught the attention of scientists.
When researchers reviewed the images and details of the encounter, they quickly realized this was no ordinary sighting. The discovery was later documented in the Marine Biodiversity journal, confirming that it was the first time an orange nurse shark had ever been recorded anywhere in the world.
Scientists explained that the shark’s unusual coloring was the result of two very rare genetic conditions occurring at the same time. The first was xanthism (also called xanthochroism), a mutation that reduces dark pigments and makes brighter colors like orange and yellow more visible. This condition is rare across the animal kingdom, sometimes observed in fish, reptiles, and birds, but never before in a cartilaginous fish such as a shark in the Caribbean.
The second condition was albinism, which affects the production of melanin. This explains the shark’s white eyes and the absence of normal pigmentation that most sharks have. Together, xanthism and albinism created a combination that made the shark’s skin glow like a creamsicle and its eyes appear unnervingly pale.
While the colors made it beautiful to human eyes, scientists pointed out that they also removed one of the shark’s most important survival tools — camouflage. Normally, nurse sharks have light brown skin and dark eyes, allowing them to blend in with sandy seafloors and reefs.
Without that natural disguise, the bright orange shark would stand out easily to both predators and prey. Despite this, the shark had already reached adulthood, a sign that it had managed to survive despite its disadvantage.
Experts also suggested that other factors might have influenced the pigmentation, including environmental stress, hormonal imbalances, or even inbreeding among shark populations. For now, the case raises new questions about the genetic diversity of nurse sharks living in Costa Rica’s waters.
The sighting sparked comparisons to other unusual animals with rare pigmentation. In April, a family in Iowa stumbled upon two albino deer during a birthday outing, and in Australia, a sanctuary recently sheltered a small mob of albino kangaroos. Cases of albinism are better documented across species, but xanthism remains far less understood, making the orange shark’s appearance even more remarkable.
Nurse sharks themselves are generally slow-moving creatures found in warm coastal waters. They are known more for their ability to use suction to pull in prey than for having razor-sharp teeth. Often considered harmless to humans, they usually grow up to 10 feet long and spend much of their time resting on the seabed.
For scientists, this single shark has opened a window into a little-known corner of marine biology. They hope future studies will uncover whether other sharks in the region carry similar genetic traits or if this was a one-of-a-kind anomaly. What’s certain is that this glowing orange shark has already made history as the first of its kind ever recorded.