On his Wikipedia page, in the 1966 - 1975 section it says it took a lot of persuasion to get him to use the wheelchair. This suggests that he wasn't in dire need of it at that point. His first child was in 1967, the last in 1979.
6. Extremely high ammonia levels in the water can damage the outer layer of skin and cause shedding. RES are tolerant of high ammonia levels while map turtles are not, so this problem is more likely to occur with Graptemys species.
The photo damage also causes the muscles of the skin to the flag and the loose skin is thick and leather. This is due to tissue damage, which is called solar elastosis. Sun damage and rosacea Excessive sun exposure is also harmful for people who have a skin condition called rosacea.