Description: 2.5 to 4.2 inches long from snout to vent. The largest of the Xantusiids, growing from about 5 to 8 inches long including the tail. A medium sized lizard with granular scales, soft skin that appears loose around the neck and shoulders, large plates on the head, lidless eyes with vertical pupils, a gular fold, and a fold of skin low on each side of the body. Two rows of supraoculars and 16 lengthwise rows of squarish scales at the midbelly. Color and pattern are variable : Brown, olive-brown, grayish, rusty, or yellowish-brown with dark brown or black spots or blotches, sometimes with full or broken light stripes edged with black along the sides of the back. Striped lizards occur on San Clemente Island, but rarely on Santa Barbara Island. The underside is slate bluish, cream or pale yellow. The undersides of the feet are sometimes yellowish

Habitat: Found in almost any island habitat that provides it protection and shade - maritime desert scrub, grassland, chaparral, oak savanna, cactus, dry streambeds, cliffs, rocky beaches, sparsely vegetated areas. Takes shelter in cracks in rocks or in the ground, and under surface objects such as rocks, fallen vegetation and beach driftwood. Santa Barbara Island is a flat tree-less plateau with grasses, small shrubs, introduced ice plant, prickly-pear cactus and Giant Coreopsis. There are a few small rocky canyons along the edge with dense vegetation.

Range: Endemic to California. Found only on San Nicolas Island off the southern California coast.

Found in these States: CA

Diet: Eats small invertebrates including insects, spiders, scorpions, and marine isopods along with plant material (which can make up to one third of its diet.)

Reproduction: Reproductive potential is low. Adults do not reach sexual maturity until their 3rd or 4th year and only about half of all females reproduce each year. Breeds in March and April. Viviporous, bearing 2 to 9 live young mostly in September.

Status: Protected since 1967. This lizard's restricted habitat has been threatened by the grazing of introduced livestock and game, (most of which have now been removed) and by introduced predators such as feral cats and possibly rats. It is also preyed upon heavily by native birds and mammals. In 1990 the USFWS categorized the status of lizards on San Clemente Island as stable. A 1991 study by Fellers and Drost determined that the population on Santa Barbara Island is not threatened. The U.S. Navy administers San Clemente and San Nicolas Islands, and has petitioned to have lizards from those islands removed from the Endangered Species List. Santa Barbara Island and Sutil Islet are protected as National Park property. On 4/1/14 the U.S. Fish and Wildlife Service removed Xantusia riversiana, the island night lizard, from the Federal List of Endangered and Threatened Wildlife.

Taxonomy: This subspecies of Island Night Lizard is not universally recognized. It occurs exclusively on San Nicolas Island which is currently controlled by the United States Navy and is off limits to the public.