I believe they're not very aware of temps sometimes.
It seems that the tortoises here will seek shelter in the heat of the day because they are programmed to do so, but if you actually put one in a hot spot or under a lamp it will not necessarily move and slowly burn.
Likewise, when they get cold their body functions slow down and maybe their brains (what there is of them) seize up, like ours do in the cold and they will just lie in a cold place and freeze to death.
If I turn off Tidgy's MVB bulb she will still walk and sit under it, seemingly oblivious to the fact that it may be colder and less lit than elsewhere she could walk to.
I've discussed this many times with other tortoise keepers.
When a tortoise evolves over millions of years, it does so in its native environment. When we move them to an entirely different environment in another part of the world, they sometimes don't have the mechanisms to deal with the new challenges. Variations among species complicate things even further. Let me explain: Sulcatas and desert tortoises dig out a burrow and they return to this "home base" automatically. They sleep in their safe hole every night. They go there to escape the heat each day. Leopard tortoises, by contrast, don't burrow and from what I have read live a more transient lifestyle. They wander around in their environment and they park wherever and whenever they want. In their native land, they can handle whatever the weather throws at them. So while Dudley and all of my sulcatas return to home base every night, which is very convenient since we have all their heating equipment set up in this home base, my leopards frequently don't return to their warm boxes. The leopards often park outside under a bush or in a corner somewhere. On a cold winter night, this could kill them if I didn't come along and put them in their heated night boxes. Tortoises seem to have a mechanism in their brain that says, "Hey! I'm too hot, I've gotta find some shade or water or somewhere cooler, or I'm gonna die." Tortoises do not seem to have a brain mechanism that says, "Hey. Its going to get too cold out here tonight, so I better move over into the electrically heated shelter area before it gets too cold and dark." It does not get too cold for a leopard tortoise in the parts of Africa where they come from. Parking under a bush above ground over night will not harm them because it won't get too cold. Here in North America its a different story.
So to answer your original question, No. Your leopards are not mentally equipped to deal with the weather in a Chicago backyard all on their own. They need your help and intuition and this has nothing to do with their age. If you allow them to choose to stay outside or retreat at will into a heated box of some sort, often they will often make the wrong choice and choose to sit out in the cold.
Yes tortoises survived for millions of years without our help, BUT, they survived in the land where they evolved and hatched, not in our backyards on another continent. Many of them also died in their native lands because they made the wrong choice when mother nature threw a curve ball at them. Matching the survival rate of wild tortoises in my enclosures is not my goal.
