Rex the Runt: How Dinosaurs Became Extinct (1991) is a Animation, Comedy, Fantasy film that follows our plasticine pooch pal Rex welcomes us to his world, introduces us to his friends, and illustrates how Bad Bob caused dinosaurs' extinction (whoops!) Rex the Runt: How Dinosaurs Became Extinct is not currently listed with streaming providers in your selected region, but availability can change over time. It has a user rating of 7.5 out of 10 from 2 votes. Fans of animation movies may also want to explore similar titles below.