The genus Manta contains two species of manta rays: the Reef Manta Ray (Manta alfredi) and the Giant Oceanic Manta Ray (Manta birostris), which are the largest species of the rays in the family Mobulidae, and the largest rays in the world. The largest recorded oceanic manta specimen was more than 7.6 metres (25 ft) across, with a weight of about 2,400 kilograms (5,300 lb), while reef mantas are typically 3 metres (9.8 ft) to 4 metres (13 ft) in disc width, with a maximum possible size of about 4.5 metres (15 ft). Manta rays are circumglobal and are typically found in tropical and subtropical waters, although oceanic manta rays can be found in temperate waters. Oceanic mantas reside in deepwater, pelagic zones, making periodic visits to cleaning stations at seamounts and coastal reefs. Minimal concrete information exists on oceanic manta movements, but they are generally believed to be more transient and migratory than the smaller reef mantas, which tend to be resident to shallower coastal habitats. Manta rays have the largest brain-to-body ratio of the sharks, rays and skates (Elasmobranchii), with ratios approaching what is expected in mammals rather than in fishes.