Porcupine Ray | Oceana

Sharks & Rays

Porcupine Ray

Urogymnus asperrimus

Distribution

Indian Ocean and Indo-West Pacific

Ecosystem/Habitat

Coastal; lives on soft bottoms near coral reef habitats

Feeding Habits

Foraging predator

Conservation Status

Vulnerable To Extinction

Taxonomy

Order Myliobatiformes (stingrays and relatives), Family Dasyatidae (whiptail stingrays)

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A layer of sharp thorns on its back gives this ray a considerable edge over any predators looking for a bite. The spikes, which are a mixture of large, cone-shaped thorns and smaller, pointed scales known as denticles, are critical for the porcupine ray as they lack the venomous barb most stingray species use for warding off larger animals. The porcupine ray is a rarely seen and distinctive ray species that unfortunately faces many threats in its range.

The porcupine ray is aptly named for its prickly body that acts as armor against a litany of predators. Stingray species are often vulnerable to the appetites of hammerhead and bull sharks, killer whales and other carnivorous fish. Though the porcupine ray has a signature whip-like tail similar to other stingrays, theirs does not hold venom for stunning predators. The porcupine ray's body is flattened into an oval-shaped disc with a rounded snout, and is usually shaded brown or grey above and white below. Its black tail stands out against its light body, and appears darker towards the tip. The porcupine ray inhabits the Indian Ocean and the Indo-West Pacific, concentrating around East Africa, the Red Sea and parts of Australia where tropical, inshore waters give way to coral reefs and sandy seafloors.

The reproductive habits of porcupine rays have rarely been observed, but females most likely retain their eggs internally as most other stingrays do until the eggs are fully developed and then the female can give birth to a live litter. Newborn porcupine rays lack the species’ characteristic sharp thorns, but are still equipped with countless denticles on the upper part of the body. Porcupine rays forage for bottom-dwelling crustaceans, marine worms and fish that burrow into soft, sandy bottoms. Sharp rows of teeth in the ray's downward-facing jaws are ideal for breaking the hard, outer shells of its prey. Porcupine rays are benthic, which means they live near the sediment surface of the ocean. Benthic rays tend to "ripple" their fins to move around above the seafloor, in contrast to pelagic rays that flap their pectoral fins.

Porcupine ray populations are declining today, and the species is considered vulnerable to extinction. Porcupine rays are not targeted by commercial fisheries, but they are often caught accidently by recreational fishermen in nearshore waters. Fewer porcupine rays are caught today as bycatch compared to years past, and researchers believe this means the species has been overexploited in its range and there are fewer individuals. Further, a porcupine ray’s preferred habitat is in populated coastal areas that are more susceptible to human activity.

Want to learn more?

Check out KELP (Kids Environmental Lesson Plans) for free marine science activities for children.

 

Additional Resources: 

http://www.iucnredlist.org/details/39413/0

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