California Butterfly Ray
Gymnura marmorata

Physical Description

• The disk or body of this ray is almost twice as wide as it is long.
• Their pectoral (side) fins are not separated from their head, leading to the triangular shape of the body.
• Their tail is short with a small stinger at its base.
• Brown or gray coloration on their back with lighter mottling; white coloration on their belly.
• They can be 5 feet wide.

Range

• Point Conception, California to Paita, Peru.
• Gulf of California, Mexico.

Habitat

• They are an inshore species.
• They are common in shallow bays and along sandy beaches.
• Found in inlets and jetties.

Reproduction

• The embryos are nourished by small yolk sacs inside eggs inside the mother and then are born alive.
• The litter size is often 4-16 pups.
• The pups have a disk of 8-10 inches in width at birth and grow rapidly.

Diet

• Crustaceans, mollusks, fin fish.

Predators

• Large fishes, especially sharks.

Interesting Facts

• They are commercially harvested in the Gulf of California for their liver oil.
• Many species of butterfly rays can quickly change color to blend into their surroundings to avoid predation.

Sources: Pierfishing.com; bullbuster.net; Navarro-Garcia et al. 2004; animaldiversity.org; Mexican-Fish.com

Photo: Nanette Oser Oselett

Come see a Butterfly Ray and its elasmobranch relatives in person at Birch Aquarium’s Shark Shores!