The amount of plants available on an island leads to restrictions in the sizes of the plant-eating animals. Dwarf titanosaurs live among the coconut palms of the seashore and in the ferny undergrowth beneath the oaks and pines further inland on the Seychelles. They feed on the undergrowth and the leaves of the low-growing vegetation. Unlike their larger relatives, the dwarf titanosaur is not a gregarious animal. It lives in small groups of two or three rather than in large herds. The group can move quite quickly through the thickets, long necks waving, when faced with an agile predator like the dwarf megalosaur. The body of the dwarf titanosaur needs smaller legs to support it, but the head is as large as that of a conventional titanosaur, and so it looks proportionally large. Dwarf animals are not unique to these islands. Dwarf forms of other large animals live on other islands in the oceans of the world, where a group of animals has become separated from the mainland population. It often happens that the isolated population has no meat-eaters to attack the adults among its numbers. Under these circumstances small and swiftly moving plant-eating animals may develop into large slow-moving forms, there being no need for speed to escape danger while they are mature. On an island, therefore, there may be dwarf species of large vertebrate animals, living beside giant species of small vertebrate animals.