Bat Ray
Myliobatis californica

Physical Description

    • Bat-like pectoral (side) fins are triangular, have rounded tips
    • Snouts are broad, short, and rounded
    • Hole called a spiracle behind each eye
    • They have one to three venomous barbed spines at the base of their long, whip-like tails
    • Brown, olive, or almost black on top; white on the bottom
    • Female bat rays are larger than males. Females’ wingspans can reach 6 feet and they can weigh 200 pounds

Range

    • Found on the Pacific Coast from Oregon to Baja California, Mexico and around to the Gulf of California
    • Also found near the Galapagos Islands

Habitat

    • Live in muddy and sandy-bottom bays, kelp forests, and near coral reefs

Reproduction

    • Females mature at 5-7 years old, and males at 2-4
    • Bat rays are normally solitary, but during breeding season, they come together in large groups
    • A courting male swims in a synchronized motion below the belly of a female and uses the spines above his eyes to maintain position
    • After a 9-12 month gestation, 2-5 live pups are born. They are approximately 9-12 inches long
    • When bat rays are born, the babies have to be careful to not sting the mothers. They are born with soft spines on their tails that are covered in a protective sheath. The spines harden and are ready for defense within a few days

Diet

    • Bat rays eat clams, shrimp, worms, other crustaceans and molluscs, and small fishes
    • They flap their pectoral fins to expose buried prey, like clams, and then use their snout to dig out prey
    • Bat ray teeth are fused into teeth that can crush mollusc shells. They crush the entire shell inside their mouth, spit out the shell, and then eat the soft mollusc body.

Predators

    • California sea lions, broadnose sevengill sharks

Interesting Facts

    • Just like sharks, their close relatives, bat rays are continuously growing new teeth.
    • Female bat rays’ eggs develop and hatch inside her body. When bat rays are born, the babies have to be careful to not sting the mothers. They are born with soft spines on their tails that are covered in a protective sheath. The spines harden and are ready for defense within a few days.
    • Bat rays often rest semi-buried in the sand. Do the “stingray shuffle” and shuffle your feet in the sand instead of picking your feet up to reduce the risk of stepping on a ray and getting stung!

Sources: Monterey Bay Aquarium; Aquarium of the Pacific; AnimalDiversity.org 

Photo: Brian McHugh    

Come see a Bat Ray and its elasmobranch (shark and ray) relatives in person at Birch Aquarium’s Shark Shores or at Living Coast Discovery Center!

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