Ostriches have a lot of unknown facts, starting from: beeing the largest bird, having the largest eye, having only two toes, consuming and storing stones, being the fastest animal on two legs to roaring like a lion. Further facts you can find them in my post.
Cats have a lot of unknown facts that have not yet been explored. Just to mention: Cats can make over a hundred different sounds, the earliest cat lived more than 4400BC ago and cats spend 70% of their lifetime sleeping. Those are a few facts I mentioned, peruse through my post to find out more.