The farallon islands, or the Devil's teeth, as they are referred to by sailors, are a group of small islands with rocky, barren terrain and treacherous underwater currents, 48 km (30 miles) off the coast of san Francisco, California. Although the islands are small, with a combined total land area of 0.41km2 (0.16 square miles), they are positioned in a major ocean current, which enables them to house dense populations of birds, rodents, seals, and other mammals.