Legend of Zelda: Can eating Dubious Food hurt you

While it seems there are a multitude of secret mounts (non-horses of any kind) that you can mount and ride around, they are not mounts that you can register/keep, while you are able to tame/ride them.

This article talks about all the different mounts and explains based on player's accounts that unique mounts such as bears are only able to be mounted, and as soon as you get off, they will walk off too. I won't post more from there as some mounts could be potentially seen as spoilers.

Horses aren’t the only animals that can be tamed – we’ve seen a player riding an elk in one video. The taming process is the same as with horses, but there are some key differences. You can’t register wild mounts, which means they’ll be off as soon as you dismount them. They also have unique characteristics – they may be slower, but provide something else in return. We’ve seen one player mounting a bear. He said he couldn’t make the bear attack, but it did seem to scare a lot of the enemies away, so there’s that.

You have to go to your Adventure Log (the screen left of your inventory) and scroll over to the Memories page. There you'll be able to revisit any restored memories.