OEMs are not actually the original manufacturer of the equipment, but are actually a company who has a relationship with the original manufacture to resell that manufacturer's product under its own name and branding.
Definition of warthog. : a wild African hog (Phacochoerus aethiopicus) that has large protruding tusks and in the male two pairs of rough warty excrescences on the face and that is sometimes placed in two separate species (P. aethiopicus and P. africanus)
Edit. 1  In Halo 3 and Halo: Reach, if you look carefully at the rims of the Warthogs, you'll notice that they say Puma. 2  This is a reference to Red vs Blue ' s scene where Simmons and Sarge argued with Grif about whether to call the vehicle a Warthog or Puma.