It's just the cave Dino's spawning everywhere.
Better chance on loot, and gifts on loot, like skins and haircuts styles.
And the eventual zombie dodo, and dodorex
I had never seen a megalosaurus before, I've heard of them just never seen one. I walk out my door and I'm all pokin my husband like "uhh, sweetie... there is a giant troodon in my yard." She lives with us now. Lol