Years ago my parents were at the seashore with my niece. My mother bought my niece a pet turtle and hermit crab. When she came home with them, her mother (my sister) forbade her to keep them due to her fear of germs (Salmonella). She had 2 smaller children in the house. So I ended up being the caretaker of these pets until my niece grew older. After she was 18 or so, she moved into her father's house, and asked for the turtle.
It is amazing how something so small could have a personality, but I am certain that s/he did. I considered him to be a male based upon that personality. His home for awhile was a small plastic habitat, and he would throw around the pebbles inside making noise so I could not sleep. And I took that to mean he was hungry, and would drop in food pellets one by one. And he could eat a lot. It got to the point where I had to place the habitat in another room at night in order not to be disturbed.
I would arrange his habitat so that pebbles were on one side so that he would not be submerged all the time, but he would not leave them be where they were. I buttressed them with a couple rocks, but still I think he would move them around if he was bored.
Another thing I noticed was that sometimes I would happen to glance over at him and see him pressed up against the glass intently staring at me. And if I looked at him, I think he would start clawing the wall of the habitat. Maybe he wanted out.
Once he bit me. I was blotting the bottom of his shell with a tissue to remove a white film when he suddenly snapped at me. I threw or dropped him in shock, but he was okay.
I think I bought him a small aquarium after that so that he could submerge and swim and dive. My niece had an even better home for him, a heated aquarium with a filter. I missed him for awhile, but now I have 2 hermit crabs. One is company for the other.