In 2024, off Costa Rica’s east coast, sport fishers stumbled upon a highly unusual 6.6‑foot nurse shark exhibiting bright orange coloration—an unprecedented case of xanthism in this species. Even more extraordinary, the shark also displayed signs of albinism, including a lack of black in its irises. This rare combination, known as albino‑xanthochromism, has almost never been seen, previously documented only in a few other marine species like an Irish Sea ray. The shark was safely photographed and released. While xanthism is typically genetic, researchers suggest environmental stressors or hormonal imbalances might also contribute. Despite its conspicuous coloring, the shark reached adulthood, suggesting its condition didn’t significantly impair survival. The findings were published in the journal Marine Biodiversity, drawing worldwide interest.
