 |
Size: Width to 6 feet.
Range: Oregon to the Gulf of California; common in bays and in shallow sandy arms along the coast.
Feeding: Primarily bottom feeders: clams, abalone, snails, echiuroid worms. |
If you are lucky enough to chance upon a bat ray in the murky waters of a muddy slough, don’t be ashamed to pinch yourself. This large, charcoal-colored fish has such an odd appearance that to catch sight of one swimming in the wild must be like watching a creature materialize from a fantasy novel.
The California bat ray, with its four-to-six foot "wing" span, has one of the most exotic combinations of features of any creature to be found in San Francisco Bay. A somewhat bulbous head and popping eyes give the ray an awkward, frog-like appearance. The head, however, gives way to a sleek, graceful body, the sides of which form huge flapping "wings," which the bat ray uses to swim. And its long, whip-like tail looks like it belongs on some kind of rodent rather than a sea creature. Altogether, the bat ray looks like a mythical leviathan, embodying in one form the creatures of land, sea and air.
In reality, the bat ray’s exotic looks derive not from myth, but from history. Myliobatis californica has been around for a long time in this area - fossils have been found that date back one million years - to the late Pliocene epoch. Today, bat rays are still a common sight in our bay and around the intertidal zone of the shallow ocean. Although its dark shadow gives off a vaguely menacing air as it cruises just under the water, the bat ray is far from being some fierce, marauding predator - unless you happen to be a crustacean or mollusk. In fact, it spends much of its time simply lying in the sand. There it waits for small mollusks, snails and crustaceans, laconically flapping its "wings" to cover itself with sand as camouflage. This action can also uncover juicy worms or shellfish, which the ray cracks open with its jaws, sucking out the meat for a quick meal. Bat rays can also dig out food using their snouts to probe into the mud or sand.
Any fearsome image the bat ray gives off may derive from a faint family resemblance to its cousins, the sharks. Unfortunately for M. californica, however, it resides a bit lower on the food chain than its relatives, and in fact, in the ocean can serve as a quick bite for a foraging shark or hungry sea lion. An excellent adapter, the bat ray is an upstanding member of the undersea community - it is not particularly picky about what it eats, and gives back to other creatures in a unique way. While digging in the dirt for food, the bat ray exposes not just the clams, crabs and worms it prefers, but also tiny organisms that smaller fish enjoy. As a result, many small fish rely on the bat ray for food, since they are unable to dig out their prey themselves.
But for humans, the beauty of this creature lies in the opportunity to observe its magnificent "flight." While it swims, a bat ray folds its side flaps in a motion that looks like a bird flapping its wings. The smooth and even rhythm it beats, as it glides along, is reminiscent of the most graceful of eagles. Bat rays can even take the simulation of flight one step further. They have been seen "jumping" out of the water, and can skim along the surface for several seconds - a motion that looks remarkably like flying.
Although often solitary, these rays have been observed to swim in packs of hundreds - and have even been seen traveling by the thousands. So next time you are visiting the Bay’s wetlands, keep a sharp eye out for the bat ray. If you are especially lucky, you will catch them in a social mood. But be warned - that tail IS armed with a stinger - the venom of which serves as a painful reminder to the curious to observe these unusual creatures from a respectful distance.
|
