For taming it is INFERIOR to death worm horns.

If tamping a Mantis on rag just kill some Ice worms, actually easier than killing rhinos and more efficient. On other maps use rhino horns for recipes such as antidote.

1 rhino horn is equal to 1 death worm horn when crafting, 3-5 rhino horns is equal to 1 death worm horn when taming