Kangaroos are a species of marsupial from Australia.
The New Scooby and Scrappy Doo Show
Scooby-Doo was jumped on and temporarily squashed by a kangaroo at a "Roo Crossing." Scrappy challenged the animal for this, but the roo picked him up, stuffed him in her pouch, and ran off with him for a while. (Scooby Roo)
Scooby-Doo! And The Legend Of The Vampire
Shaggy Rogers and Scooby-Doo rode them while touring the outback. Shaggy rode bareback, but Scooby rode in the pouch until the kangaroo joey ejected him.