Round Stingray
Urobatis halleri

Physical Description

• Main body is smooth and almost round.
• Short sturdy tail, less than half the length of body. Spine about halfway down the tail, on the top of the tail.
• Tail ends in caudal (tail) fin. Have no dorsal (back) fins.
• Tan, brown, or gray coloration, plain or mottled coloration on back, with a whitish belly.
• Juveniles: Born at 2.5-3 inches wide, miniatures of the adults.

Range

• From Humboldt Bay, California to Panama City, Panama.
• Most common in southern California and northern Baja California, Mexico.

Habitat

• They prefer sandy or muddy bottoms.
• Found in rocky reef areas, estuary mouths, beaches, and shallow bays.
• Normally found in shallow water but can be in depths of 300 feet.

Reproduction

• Round rays reach sexual maturity at 2 and a half years old.
• Mating is most often from March to April.
• The male’s electroreceptors become particularly sensitive during mating season and can detect buried females in sand.
• Gestation is about three months; at first the egg gets all nourishment from the yolk sac, then it transitions to nourishment from the mother.
• One to six pups are born alive; larger females have more pups.
• Pups are independent from birth.

Diet

• Eat lots of benthic invertebrates, such as worms, shrimp, amphipods, clams, small mollusks, and small fish.

Predators

• Round stingrays are a favorite food of leopard sharks, as well as elephant seals, giant sea bass, and other sharks.
• In the northern part of their range, they are also eaten by northern elephant seals and black sea bass.

Interesting Facts

• Round stingrays bury themselves completely in the sand except for their eyes and spiracles (holes beneath their eyes). It is very important to perform the “stingray shuffle” and shuffle your feet in the sand so that they see you coming and swim away. If you step right on one, you might get stung!

Sources: Aquarium of the Pacific; Florida Museum 

Photo: Don Balch