I adopted my turtle Mr. T when he was approx. 1 year old. A roommate had him in a shallow salad bowl with water (no heater, UVB, basking area, not enough room to swim, etc.) for about a year. He would stay in his shell except to eat. I didn't know she had him until one day she asked if I could care for him when she was out of town for a few days. We hit it off and played together ... he was a vigorous climber and very athletic and active. When I placed him on the window sill he climbed up the window screen ... I spotted him with hands under him and caught him if he fell. We bonded over climbing and he'd climb up my leg and on my lap and up my shirt ... I'd always spot him and make sure he couldn't take a tumble. If placed on a chair, table, or bed for ex. he'd run towards the edge and I'd have to catch him before he would run off the edge.
I thought it unusual that he didn't have a natural fear of falling off the edge of things. So I'd always catch him.
These days when I let him crawl around on my bed (he's fast) I have to be constantly vigilant that he doesn't run off the edge (bed surface is just about 1.5 feet above the floor, but it's still a drop). He's approx. 17 years old and if I place him on anything that's raised above the ground, could be just 6", 1', 2'', 4", etc. he'll just walk or walk off the edge without concern. When he was little he took some tumbles and one would think he;d learn by falling, but apparently not.
He has good eyesight. He simply has no concept of heights and falling. Bizarre. Is this normal for turtles? If not can this be trained?