They are not in minecraft by default. You have to install a mod...Mo Creatures I think it is.
You dont >:D
Mo Creatures is a modification (mod) for Minecraft. You can get this mod by downloading it from The Minecraft Forums.
Mo Creatures is free. If you didn't know that, you have a bit of learning to do before you attempt to install a mod.
You download it, get the modloader, and install it. Check youtube to see the steps one by one.
Mo' Creatures is a modification (mod) for Minecraft. It adds new mobs like sharks, elephants, horses and more.
Lions can only be found on Minecraft if Mo' Creatures Mod is used. If you would like to keep your lions, keep the Mo' Creatures Mod.
Horses are not a mob yet in Minecraft, but they are available on Mo' Creatures.
On Minecraftforums
Yes it's compatible with mo creatures but I'm not sure about mo creeps and weirdos.
The only way trolls exist on minecraft is if you have the mo' Creatures mod
If you google mo's creatures, you'll get a singleplayer version Be careful Make sure you have the correct version