So, in my group I seem to usually be able to answer most rules questions that come up during our games but this last one I admit I was somewhat stumped. Our groups Paladin was given a chance to adjust his character a bit and decided to switch from going with the weapon bond to the bonded mount instead. I know the ability description talks about how they level up as a druids animal companion, but also specifically talks about them being mounts. Our Paladin mentioned that they wanted to take a tiger as his bonded mount, and use it more as an animal companion but the question was raised that the tiger isn't really a mount and we did not know if that was actually a possible choice. Reading the section on Paladin mounts again, it really doesn't give much of a list on possible animals for mounts other than to talk a bit about warhorse, riding boars, and riding dogs. So my question since I've been asked to look it over was just what animals are fair game for a Paladin bounded mount? Is there something I'm missing listing more info on this? Any help is most welcome.
Well, it's up to the GM at the end of the day. The reason why it lists horses for example is because they start out as Large Creatures if you take them as a druid companion.
If your Paladin chose a Tiger Mount, he couldn't actually ride it until 7th level, Unless he's small.
It really hinges on whether your GM determines that a Tiger is suitable as a mount.
I would suggest looking at the Cavalier class and the Beast Rider Cavalier archetype for an idea of how to judge power. Cavaliers as a base class are explicitly able to ride Camels and Horses, but says GMs may select other suitable options. The Beast Rider opens up many other mount options as the cavalier gains in levels.