You can put hats on 'em. Hope this helps

I once had an otter that I named harry otter , he was a great otter he got me all the silica and black pearls I needed, he once saved me from a megalodon , he kept me warm to, he was a great companion I took him almost everywhere,but one day I was farming pearls with him I threw him at a fish to get pearls from it but instead he disappeared I looked and looked for him only to not find him but uneven got a message that he was dead, he's still out there somewhere, I still look for him to this day. #prayforharryotter

The otter can be very useful for gathering fish meat — it will harvest fish on demand. You can also use it to forage for Silica Pearls, and it will occasionally find Black Pearls.

When doing artifact runs take it with you to store multiple artifact on it

Increasing melee damage increases the hypothermic and hyperthermic insulations on the carrier.