The Land Before Time V: The Mysterious Island (1997)

When a swarm of "leaf-gobblers" devours all the green food in the Great Valley, the herds move on to find another valley of greens and in the process, Littlefoot and his friends Spike, Cera, Petrie and Ducky wind up on an island in the middle of the Big Water. They're reunited with Chomper...Along with his nasty, hungry parents.