Land Before Time Volume 5 - The Mysterious Island

One day, a cloud of "Swarming Leaf Gobblers" descends upon the Great Valley and devours every plant in sight. Now the once-lush landscape is barren and empty, and the Valley herds must search for a new home until the leaves grow back. But when quarreling among the adults threatens to separate them, Littlefoot and his prehistoric pals set off on their own...

Synopsis

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 are reunited with Chomper... Along with his nasty, hungry parents.