On Isla Sorna, there are many dinosaurs, and one of the fastest ways to get around is to ride them. (Fastest, not easiest.) Unfortunately, they don't like being ridden. Bring a bit and reins.
Rding a dinosaur is difficult. You must first make a Ride check directly opposed by the animal's Hit Dice. If it gets spooked, angry, or attacked, you must make a Handle Animal Check that is opposed by th animals STR+(STR bonus).
(The list will get longer as I find resonably sized dinosaurs to be made into mounts. I'll take suggestions as well.)