This shark occurs in cool to warm temperate waters, both inshore and offshore (Compagno in prep). It is most often found on or near the bottom in shallow water from the intertidal to 20m depth, and less commonly down to 91m depth, in flat sandy areas, mud flats, and bottoms strewn with rocks near rocky reefs and kelp beds (Compagno in prep). The leopard shark is commonly found in shallow, enclosed, muddy bays, often entering them as the tide rises and leaving when it retreats (Compagno in prep).
Leopard sharks are viviparous, without a yolk sac placenta, and the female produces from 4 to 36 offspring in an annual reproductive cycle. Gestation time is 12 months, and size at birth is 17 to 25 cm TL (Ackerman 1971, Compagno 1984, Kusher 1987, Kusher et al. 1992, Smith 2001, Compagno in preparation). Age at maturity for females is between 10 and 15 years and 105 to 135 cm TL. Males mature between 7 and 13 years and at 100 to 105 cm TL. Maximum age is at least 24 yrs, but is estimated to be about 30 years, and the maximum size is 198 cm TL with reports of sharks up to 213 cm TL (Miller and Lea 1972, Feder et al. 1974, Kusher et al. 1992, Smith et al. 2003). Leopard sharks grow slowly, reportedly averaging less than 2.2 cm per year, with fish of the same age varying greatly in size (Kusher et al. 1992). The fastest growth takes place prior to maturity; large fish are particularly slow growers, e.g., a 125 cm fish released in September 1979 in San Francisco Bay measured only 129 cm when it was recaptured in November 1991 at Santa Cruz--gaining only 4 cm in twelve years (S.E. Smith unpublished data).
Bays and sloughs appear to be important nursery areas in the north. Reported nursery areas include San Francisco Bay, Tomales Bay, Elkhorn Slough, Humboldt Bay, San Diego Bay, Catalina Harbor, and Bodega Bay (Eigenmann 1891, Bane and Bane 1971, Talent 1985, Smith 2001, Ebert 2003). In San Francisco Bay and Elkhorn Slough, California, parturition appears to occur from March through September, with a peak in April and May (Ackerman, 1971, Talent 1985, Smith and Abramson 1990). It also reportedly occurs between March and July in Humboldt Bay, Tomales Bay, Morro Bay, Santa Monica Bay and San Pedro Bay (Monaco et al. 1990). In San Diego Bay parturition is reported as occurring in September (Eigenmann, 1891). In Humboldt and San Francisco Bay, females have been observed releasing their young in beds of eel grass (Ebert 2003), while in southern California females are thought to release their pups along more open coastal areas, and have been observed giving birth to young in water 1m in depth over a shallow flat in Catalina Harbor, the pups milling about in water only 0.3 m deep (Smith 2001). Newly born pups are reportedly found in northern California bays and sloughs in April and May; also in the shallow surf zone in more southerly areas such as Santa Monica Bay in southern California around late May and June where they were harvested by hook and line for the aquarium trade in the late 1980s and early 1990s (S.E. Smith pers. obs. 1991). Juveniles are often found in more sheltered, shallow, inshore areas such as bays, mudflats, and tidal creeks (Barry and Cailliet 1983).
This shark is an opportunistic benthic feeder, devouring a variety of invertebrates and fishes, including the fat innkeeper worm (Urechis caupo), crustaceans (grapsid crabs and shrimp), clam siphons, teleosts, fish eggs, and small elasmobranchs. They may disturb the mud and use suction to capture prey. Their diet shifts with the season and the size of the shark (Russo 1975, Talent 1976, Ebert 2003). Pups caught in the surf zone along sandy ocean beaches in southern California reportedly feed heavily on sand crabs and presumably other sandy-bottom invertebrates. Predators on leopard sharks include the sevengill shark (Notorynchus cepedianus), and the great white shark (Carcharadon carcharias); man is probably the most important predator.
Strong swimming and nomadic, they are known to suddenly appear in an area, and then move on - possibly in relation to feeding or reproductive behaviour. They often occur in schools, sometimes with smoothhounds, spiny dogfishes, sevengills, and bat rays. Schools are often segregated by sex and size, and newborn leopard sharks have been observed to form loose schools (Feder et al. 1974; Ebert 2003). They are seasonally abundant in bays and estuaries (such as Elkhorn Slough, Humboldt Bay, Tomales Bay, Bodega Bay, and San Francisco Bay) during the spring and summer, and during the winter they often move out of the bays to coastal waters, likely as a result of decreased salinity and temperature due to winter storms and rain. In San Francisco Bay, California, the population is mainly resident but about 10% move out of the bay in fall and winter (Smith and Abramson 1990, Hopkins 1993, Ebert 2003). Their movements in several bays are strongly correlated to tides. During incoming tides they move into shallow mudflats to forage and retreat to deeper water as the tide goes out (Ackerman et al. 2000, Ebert, 2003). They appear to exhibit limited long distance movement. There have been several instances of sharks travelling between Monterey Bay and San Francisco Bay, and one shark tagged in San Francisco Bay was recaptured in Santa Monica Bay in southern California 10 years later, but in general movements appear to be limited (Smith 2001).
Along beaches in southern California it is not uncommon to observe large groups of leopard sharks in or just beyond the surf zone. Generally timid and wary around divers, this species is not considered dangerous, though there is a recorded minor attack on a skin diver in 1955 in California (Feder et al. 1974). Groups confined in aquaria have been observed to form a loose social hierarchy, where larger individuals assert dominance over smaller ones by gentle pectoral fin nipping (Smith pers. obs. 1979).