Shark corneas are used in eye transplants and shark bone marrow can be used to graft human bones.
132
The oldest creature ever found was Ming the clam at an admirable 507 years old.
16
There is a sea snail that wears a suit of iron plated armor. It is the only known animal to use iron sulphide as skeletal material.
9
The Basenji dog is the only dog that is not able to bark.
4
Whales and dolphins can't taste anything other than salt.
11
Sergeant Stubby was the only war dog to be promoted to sergeant through combat in WWI. He saved his regiment from surprise mustard gas attacks, found and comforted the wounded, and even once caught a German spy by the seat of his pants, holding him there until American Soldiers found him.
16
There's a young hippo and a 130+ year old tortoise in a Kenyan wildlife preserve who are best friends and they even sleep and play together.
40