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When it's summer, get ready for chondrichthyes! CREATURE FEATURE: bat ray

Updated: Aug 7, 2018

During the spring and summer seasons, we see an increase of cartilaginous fish populations in the SF Bay. This week's creature is the bat ray

The bat ray (Myliobatis californicus ) is a fish commonly found in the eastern Pacific Ocean, ranging from Oregon, United States, to Baja California, Mexico. These animals are mostly common in shallow bays, but also occur along the open coast, around islands, kelp beds, near rocky shores and sandy beaches.

Rays, sharks and skates are closely related cartilaginous fish--but what's the difference? Basically, rays and skates are flattened cartilaginous fish and rays belong to three scientific orders: Pristiformes, Myliobatiformes and Torpediniformes. This animal's common name is attributed to its dark brown to black coloring on the top of its body and the broad, angular shape of its pectoral fins that look like "wings". Besides the "wing-like" pectoral fins,

this ray has a long tail, double the length of it's body with a

venomous spine at the tail base. (pictured left)

Compared to other fish of the cartilaginous type, bat rays grow relatively fast, reaching maturity at ages between 2-3 years for males, and 5 years for females. Females can have up to 12 pups per litter, but smaller litter sizes are more typical.

As they're commonly spotted in a variety of marine habitats, these creatures have the skills to thrive in a variety of conditions, making them easily adaptable to life in captivity. For this reason, they are often displayed in aquariums for viewing and touching.

Touching? But wait, what about the venomous spine at the base of its tail?

Marine Science Institute Science Instructors are specifically trained to safely handle bat rays. Safety is the priority for both the animal and program participants, whom we encourage to interact with the animal when there is an opportunity. In aquariums where visitors are allowed to freely touch bat rays in open tanks, the spines are removed to eliminate any chances of potentially painful encounters with the venom.

Of course, there's so much more information to share about these amazing animals! Join us on a Discovery Voyage and get involved with MSI for a chance to see this animal up-close, and to learn more about all the incredible marine life found in the San Francisco Bay.

Produced and Edited by Naomi Deal


Resources and References:

  • Bester, Cathleen. Myliobatis californica . Ichthyology Collection. Dickinson Hall Florida Museum. University of Florida. 2018. . July 2018.

  • van Hees, K., Pien, C., Ebert, D.A., Cailliet, G.M. & Smith, W.D. 2015. Myliobatis californicus. The IUCN Red List of Threatened Species 2015: e.T39416A80677869. August 2018.


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