what do they prey on?
Large sized wild herbivorous hoofed mammals.
Wolf
Like all land mammals that are pack hunters, the wolf feeds predominantly on wild herbivorous hoofed mammals that can be divided into large size and medium size , and have a body mass similar to that of the combined mass of the pack members. 
from where does the word 'wolf' come from? From Old English.
wiki:19613068
Wolf [SEP] Diet
Like all land mammals that are pack hunters, the wolf feeds predominantly on wild herbivorous hoofed mammals that can be divided into large size and medium size , and have a body mass similar to that of the combined mass of the pack members. The wolf specializes in preying on the vulnerable individuals of large prey, with a pack of 15 able to bring down an adult moose. The variation in diet between wolves living on different continents is based on the variety of hoofed mammals and of available smaller and domesticated prey. In North America, the wolf's diet is dominated by wild large hoofed mammals (ungulates) and medium-sized mammals.