opportunistic hunter has also been known to eat ghost shrimp, polychaete worms, and the young of smoothhounds, shovelnose guitarfish (Rhinobatos productus), and bat rays (Myliobatis californicus). Eelgrass (Zostera) and algae may be swallowed incidentally. The leopard shark captures prey by expanding its buccal cavity to create a suction force, which is facilitated by its labial cartilages swinging forward to form the mouth into a tube. Simultaneously, the shark protrudes its jaws forward to grip the prey between its teeth. As with other sharks, the teeth of the leopard shark are periodically shed and replaced; it takes 9–12 days for a replacement tooth to move into position. Leopard sharks have been caught with stomachs filled with clam siphons, which the sharks seize before the clams can retract and break off with a levering motion of their bodies. On occasion, the shark tears the entire clam body out of its shell this way. Other sharks examined have had stomachs containing whole innkeeper worms with no bite marks, suggesting that the sharks sucked them out of their burrows. Under a hollow bridge support in San Francisco Bay, a group of leopard sharks and spiny dogfish have been observed feeding on a dense school of anchovies by slowly swimming counterclockwise through the clockwise-swimming school, and swallowing any anchovies that accidentally entered their open mouths. In some places, this species feeds only on a few prey types and little else (e.g. innkeeper worms and cancrid crabs in Tomales Bay, jack silverside (Atherinopsis californiensis) eggs and the crabs Romaleon antennarium and Metacarcinus magister in Humboldt Bay). The predominant prey taken depends on location, time of year, and age. For example, in the Elkhorn Slough at Monterey Bay, cancrid crabs and innkeeper worms are mostly eaten in winter and spring, fish eggs from winter to early summer, bony fish in summer, and grapsid crabs and clams in fall. Young sharks feed mostly on crabs and transition to clam siphons, fish eggs, and innkeeper worms once they reach long. The largest sharks are the ones that consume the most fish. Life history The leopard shark is aplacental viviparous, with the developing embryos sustained by a yolk sac until birth. In northern areas, females use bays and sloughs as nursery areas, while to the south they give birth in more open areas. Known breeding grounds along the coast of California include Humboldt Bay, Tomales Bay, Bodega Bay, San Francisco