Kevin, it could have been two turtles of the same species housed together and one still climbed over another. Recall, dear, in the wild several species coexist together. The issue about separating them in tanks is promoted by some breeders only. Professional caretakers, aquariums, zoos, etc., already house various species of animals together without problems. What they don't have in common with opposers of this natural practice is a veterinarian who regularly checks the animals...

Recommending lightbulbs over natural sunlight to people is more of a display of ignorance than anything else.
Leave the cat food for the cats. If it comes in a bag or a can, you should not feed it to your tortoise. After all, it is the typical, sound advice I am sure *your* reptilian specialist has shared with you!

Wanda