For a vast lifeless desert, Tatooine sure did host a lot of large mammalian beasts of burden. The shaggy jerba was a smaller example, carrying cargo on its broad back.
The reptilian dewback roamed the dunes of Tatooine, roaring loudly but usually not causing any trouble. They were docile enough to be trained as stormtrooper mounts.
The humble luggabeast was forever destined to haul goods from one desert to another across Jakku. One of these semi-mechanical quadrupeds carried a scavenger named Teedo, and temporarily, his captive droid named BB-8.
Gungans lived in harmony with the environment. It was only fitting that they rode the humble kaadu into battle, which were far more intelligent than the average speeder.