Musk Oxen
MUSK OX (Ovibos moschatus), plural musk oxen, shaggy-haired Arctic ruminant of the family Bovidae (order Artiodactyla). Musk oxen are stocky mammals with large heads, short necks, and short, stout legs. Their name derives from their musky odour and from their superficial resemblance to the ox, though they are not closely related to cattle. Musk oxen are closely related to the mountain goat, chamois, and serow and are placed in the bovid subfamily Caprinae, along with the true goats and sheep. –Online Encyclopedia Britannica
This description of the musk ox as a relative of the goat helps to account for Moore’s title as well as the line that says the musk ox
“browses goatlike
on hind legs.”
Marianne Moore: Poetry 