Bat Ray for breakfast?

 

 

River Otter (Lontra canadensis) chewing on a Bat Ray (Myliobatis californica) in Bodega Harbor on 9 March 2026.

 

The wind hadn't picked up yet, so there were some nice views of the otter swimming in shallow water along the shoreline:

 

 

 

 

 

 

P.S.  The otter seemed to be having trouble eating the Bat Ray, perhaps due to its thick skin?  Eventually it left the ray behind and moved on.

 

Ripple effect

  

The fin of a Bat Ray (Myliobatis californica) at sunset.

Bat Rays are powerful swimmers and since this was a calm night, sometimes their strokes created wide-ranging ripples across the surface of the harbor:

 

 

Photographed from the Bodega Bay Post Office on 27 August 2021.

A thorny identification

While conducting a survey on the beach yesterday (31 March 2017), we noticed a Turkey Vulture in the distance.  We could tell it was feeding on something, but couldn't tell what it was.

 

When we got closer, the vulture had flown off, so we went over to look at what had attracted the vulture's attention:

 

At first I thought it was an electric ray, but there were several characters that didn't seem right.  After doing some more research, I believe this is a Thornback Guitarfish (Platyrhinoidis triseriata) — the first I've seen.

It's especially important to note that the caudal fin (at the tip of the tail) is relatively small; the two dorsal fins (on the right side of the photo) are about equal in size; and there are three rows of prominent spines running down its back and along the tail (sorry I don't have better pictures of those!). 

Thornback Guitarfish prefer shallow water and sandy or muddy bottoms.  They are known to occur as far north as Tomales Bay.  Have you seen them in Bodega Bay, or anywhere further north?

P.S.  To compare with a Pacific Electric Ray, review the post from 5 February 2014.

 

It's electric!

 

Don't worry, the bicycle rider associated with this helmet (Lewis) was not eaten by this fish!  ;)

Lewis spotted the ray washed up along the shoreline of Bodega Harbor while riding his bike...and he placed his helmet next to it for scale.

This is a Pacific Electric Ray (Torpedo californica).  It was ~3 feet long and ~2 feet wide.  It has a very distinctive shape.  Here's a slightly closer view (without the helmet):

 

Look for a variety of features: dark gray coloration; a very rounded disc with a relatively straight leading edge; a short tail with a triangular caudal fin; and two dorsal fins (the front one larger than the back one — see next image).

In the picture below, the caudal fin is broad and triangular at the far left.  The dorsal fins are located on the ridge between the rounded disc and the caudal fin (the front dorsal fin is flopped over, while the back dorsal fin is standing upright).  In this image, if you look closely at the skin of the ray, I think you'll also be able to see some smaller dark spotting which is part of the coloration of the ray.

 

Pacific Electric Rays are endemic to the northeastern Pacific Ocean.  They occur from British Columbia to Baja California, but apparently are more common south of Point Conception (preferring waters from 10-13°C or 50-55°F).

Here's a closeup of the front of the disc, showing the small eyes and the spiracles (holes just behind the eyes).  Water is drawn in through the spiracles and then passed over the gills.

Pacific Electric Rays can produce powerful electric shocks — up to 45 volts!  This is strong enough to "knock down an adult human."  They use electric shocks to stun prey and in self defense.

I don't know how common Pacific Electric Rays are in the Bodega Bay area.  Just asking around a little bit today, it sounds like they might be relatively rare here.

P.S.  Alright, this last part is only for fans of the electric slide.  I couldn't help it!  When looking at this ray today, I was reminded of the song, Electric Boogie.  Do you know it?  There are several lines that are quite appropriate when thinking about this fish:

It's electric!

(Boogie woogie woogie)

You can't see it

You gotta feel it 

Oooh, it's shocking

Now you can't hold it

But you know it's there

It's electric!

This song was written by Neville Livingston (a member of The Wailers) and performed by Marcia Griffiths (a member of the I Threes, Bob Marley's backup singers).  If you need a refresher:

http://www.youtube.com/watch?v=3PyLFzcTiYA&feature=kp

A shocking discovery

 

We were walking along the inside of South Beach in Chatham today and discovered this unusual animal washed up on the sand.  You can see that it had the attention of both Eric and a young gull!

Here's a closer view from the side:

 

This is an Atlantic Torpedo Ray (Torpedo nobiliana).  I remembered that they sometimes strand on Cape Cod beaches in the fall, but I'm not sure if anyone has figured out why.  This individual was about 4 feet long.

Note the very circular shape and the relatively straight front edge of the disc.  The tail is short and the caudal fin (tail fin) is large and paddle-shaped (see below).

 

Torpedo rays are sometimes called electric rays.  They have electric organs that produce powerful electric shocks that stun their prey (primarily fish).

I found a couple of good fact sheets about Atlantic Torpedo Rays online.  If you're interested in learning more about them, check out the FLMNH Ichthyology Department web site or this page from The Shark Trust.

Bat Ray...Bat Ray...Bat Ray

(Sung to the tune of the Batman theme song)

The wings (pectoral fins) of a Bat Ray (Myliobatis californica) disappearing below eelgrass (Zostera marina) in Bodega Harbor.

These photos were taken from the Spud Point Marina breakwater on 30 April 2012.  Because the breakwater extends 1300 feet into the harbor, it's a great place to look for marine life.

Bat Rays are found along the Pacific Coast from Oregon to Baja (and around the Galapagos).  They prefer shallow bays and estuaries, and can also be seen in kelp forests and over rocky reefs.  They are sizable fish, with a maximum width from wingtip to wingtip of ~1.8 meters (6 feet) across.

Often your first clue to the presence of a Bat Ray is the appearance of the wingtips flapping above the surface.  They are flexed upward synchronously, and look somewhat similar to the dorsal fins of sharks...but they're paired, and are floppy, more like the fin of an Ocean Sunfish (Mola mola).

 

Bat Rays feed on invertebrates — e.g., molluscs (clams), crustaceans (crabs, shrimp), and worms.  They use their pectoral fins and prominent snout to dig pits in the mud, exposing invertebrates below the surface.

While observing them recently, it was fun to follow the clouds of sediment in the eelgrass bed as the rays were feeding (it reminded me of watching bubble clouds created by humpback whales).

 

Bat Rays have unusual teeth — they're flattened and hexagonal in shape, ideal for crushing and grinding (imagine trying to break a clam shell in your mouth).  It's worth looking at this picture of a Bat Ray jaw and teeth (scroll down to the 5th image).