For Taming them:

-Find one (Snow dome)

-Clear the aria

-Place gigantbeartraps around you

-Agrro the Mana

-Shoot narcotic arrows or darts on it until it is unconscious

-Kill some mammoths or rhinos for prime meat

You have tamed a Managamr. (for this method it is advised to have good amor)

More Managarmr Taming & KO Tips