Diamond Stingray

Fascinating facts about the Diamond Stingray

• A recorded female 69 cm (27 in) wide ray had gorged on at least 30 small crabs; smaller fish often trail the ray while it forages.
• Hundreds of these rays can gather on a sandy flat, and smaller fish often follow, feeding on the disturbed invertebrates.
• Females give birth to just 1–4 pups each summer, but the embryos pause development for ten months, either storing sperm or entering a dormant state, before a rapid 2–3-month growth spurt. This delayed-development strategy means each generation takes years to replace, making the species especially vulnerable to overfishing. It highlights how a single reproductive quirk can dictate a species’ survival odds.
• Despite living in shallow waters up to 30 m (98 ft) along the Pacific coast, the ray has been recorded as deep as 355 m (1,165 ft) off Hawaii, suggesting a far broader depth tolerance than previously thought. This hidden depth range may offer refuge from coastal threats, yet it also complicates conservation because the ray’s true habitat needs are still being mapped.
• In Mexican artisanal fisheries, this ray makes up about 10 % of the total annual shark-and-ray catch, becoming the most common ray landed in Bahía Magdalena. Its high market value and easy capture in demersal gillnets drive significant removals, underscoring why the IUCN lists it as Vulnerable and why better management is urgently needed.

At a glance

About the Diamond Stingray

The diamond stingray (Hypanus dipterurus) glides over the Pacific’s sandy and muddy flats with a disc shaped like a perfect rhombus, its edges angular and its dorsal surface a uniform olive-brown that darkens to black on the long, whip-like tail. Rows of low tubercles line the midline and shoulders, while the tail bears a single serrated spine near its base and conspicuous dorsal and ventral fin folds that set it apart from its close relative, the longtail stingray. Typically reaching a disc width of about one metre, females can grow even larger, and the ray’s eyes sit just above large spiracles that allow it to breathe while buried. By night it becomes a bustling predator, often forming aggregations of hundreds that hunt burrowing crustaceans, molluscs and small bony fishes. Using powerful jaws and molar-like teeth, it creates negative pressure to suck prey from the sand, and it can even excavate pits with rapid disc undulations and jets of water, a behavior that stirs up invertebrates for trailing fish such as Mexican hogfish and Galápagos porgies. A surprising trait is its ten-month period of sperm storage or embryonic diapause, allowing embryos to pause development until conditions are optimal, after which they mature in just two to three months.

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