Rhinos, Elephants, and Hippos used to be considered a group, called Pachyderms, based on some similarities in skin and size. We are all gray, big, and relatively thick-skinned. For the record, further studies have shown We are not related, one to another.
Of course, all of Us knew that, but Science didn’t know it. (All Critters are used to these mix-ups. We don’t take it to heart.)
There is a common idea that having thick skin proves Rhinos are insensitive. All We have to say to that is “nuts”.