have shown that snout length is indicative of reproductive behaviors, as great snout length is correlated with ovarian follicle growth, which increases sexual activity of the female subspecies. Garter snakes are practically harmless to humans. Their bites are fatal to their prey, but only cause a mild irritation for humans. With mildly toxic venom in their saliva, garter snakes possess no fangs. Habitat The preferred habitat of the San Francisco garter snake is a densely vegetated pond near an open hillside where it can sun, feed, and find cover in rodent burrows; however, markedly less suitable habitat can be successfully used. This subspecies can also be found in forests with dense canopies. Temporary ponds and other seasonal freshwater bodies are also appropriate. This subspecies avoids brackish marsh areas because its preferred prey, the California red-legged frog (Rana draytonii), cannot survive in saline water. Emergent and bankside vegetation such as cattails (Typha spp.), bulrushes (Scirpus / Schoenoplectus spp.), and spike rushes (Juncus spp. and Eleocharis spp.) apparently are preferred and used for cover. The zone between stream and pond habitats and grasslands or bank sides is characteristically utilized for basking, while nearby dense vegetation or water often provide escape cover. The subspecies occasionally uses floating algal or rush mats, when available. The biggest population is found in a protected tract owned by San Francisco International Airport. Diet San Francisco garter snakes forage extensively in aquatic habitats. Adult snakes feed primarily on California red-legged frogs (Rana draytonii), which are federally listed as threatened. They may also feed on juvenile American bullfrogs (Rana catesbeiana), but they are unable to consume adults; in fact, adult bullfrogs prey on juvenile garter snakes, and may be a contributing factor in the population decline of the San Francisco garter snake. Newborn and juvenile San Francisco garter snakes depend heavily upon Pacific treefrogs (Pseudacris regilla ) as prey. If newly metamorphosed Pacific treefrogs are not available, the young garter snakes may not survive. San Francisco garter snakes are one of the few animals capable of ingesting the toxic California newt (Taricha torosa) without incurring sickness or death. Taxonomy and relation to other garter snakes For a brief period from 1996 to 2000 there was confusion over the differentiation of the San Francisco garter snake from two other subspecies from California, the California red-sided garter snake (T. s. infernalis) and the red-spotted garter snake (T. s. concinnus). Barry petitioned