the day, and sometimes lies still on the bottom. In Tomales Bay (among other similar regions), the leopard shark follows the tide onto mudflats to forage for food, retreating just fast enough to prevent being stranded or trapped as the water recedes. At Santa Catalina Island, resident sharks spend the day together in the shallows and at night, they disperse into deeper water, up to away. From birth, leopard sharks form large schools, generally segregated by age and sex; these groups may intermingle with grey or brown smoothhounds (Mustelus californicus and M. henlei) and spiny dogfish (Squalus acanthias). These schools are apparently nomadic, often appearing suddenly in an area for a few hours before vanishing just as quickly. In captivity, larger sharks have been observed establishing their dominance over smaller individuals via light nips to the pectoral fins. During summer days, large aggregations of mature females assemble in shallow bays and estuaries, dispersing at night. As these females follow the warmest patches of water (allowing them to raise their internal body temperatures by up to 3 °C/5.4 °F), they are speculated to be taking advantage of the heat to speed their own growth and that of their gestating young. The membership of these aggregations is inconstant, with individual females periodically switching between different sites scattered over several kilometers. Compared to the related grey and brown smoothhounds that share its range, the leopard shark has smaller and more numerous red blood cells, allowing it to process oxygen more efficiently. This may be an adaptation for foraging in deoxygenated estuarine environments. Their eyes contain very few cone cells, likely due to the murky water they inhabit. Small leopard sharks fall prey to larger sharks such as the great white shark (Carcharodon carcharias) and the broadnose sevengill shark (Notorynchus cepedianus). On one occasion, a sevengill shark was seen ambushing a leopard shark on a tidal mudflat in Humboldt Bay, striking with such momentum that the larger predator momentarily beached itself. Known parasites of this species include the tapeworms Phyllobothrium riseri, Lacistorhynchus dollfusi and Paraorygmatobothrium barber, as well as the copepods Echthrogaleus eoleoptratus and Achtheinus oblongatus. Feeding The diet of the leopard shark consists of small benthic and littoral animals, most significantly crabs (Cancridae, Grapsidae, and Hippoidea), shrimp, bony fish (including anchovies, herring, topsmelt, croakers, surfperch, gobies, rockfish, sculpins, flatfish, and midshipmen), fish eggs, clams, and the echiurid fat innkeeper worm (Urechis caupo). This