But looking at the definition of the word dominant... Ya gotta go with people, since people are the only species to domesticate or cage any other critter larger than an aphid.

dom·i·nant
   [dom-uh-nuhnt] Show IPA
adjective
1.
ruling, governing, or controlling; having or exerting authority or influence: dominant in the chain of command.
2.
occupying or being in a commanding or elevated position.
3.
predominant; main; major; chief: Corn is the dominant crop of Iowa.
4.
Genetics . of or pertaining to a dominant.
5.
Music . pertaining to or based on the dominant: the dominant chord.