as mentioned it sounds like they didn't skin it (mistake 1) and didn't gut it all that well.
All that said, if you leave an animal of that size, laying on the ground, even gutted, it won't cool. That hide is built to insulate and hold heat in. Add to that that it's laying on the ground, so air isn't circulating.
Things that big MUST be skinned and quartered and gotten off the ground.