Being cold blooded an Alligator has no way to regulate their body temperature like a person. So they find all types of other ways.
One way is to have a hole to climb in. Hey, little lizards do it, why not really big ones. The exposed roots above is perfect and they just move back and forth between sun and shade.
From a different angle you can see it’s not very big. There can be a few hundred Alligator here so it’s first come, first serve…or the biggest moves in and that’s it.