Good question. My answer is: yes . . . and no, not necessarily. Animism is not a religion, per se, but a belief that underlies most religions, that is, the belief that at least some material being is permeated with spirit. People who identify as animists, however, both historically and today, believe that spirit permeates all beings, not just certain kinds of beings like humans and their gods and pets.
But this belief in spirit does not define what kinds of god-beings exist and animistic thinking runs the gamut on the matter. One may be animist and believe in a monogod, in many gods, or in greater-than-humans but not gods.
Indigenous or tribal Animists have historically focused on local deities and the life-force of their home-place, as well as nature spirits, ancestral beings, totems and nonhuman guides. Our animists ancestors had the good sense to leave whatever lay beyond their sensory experience alone. They were not abstract thinkers, and their animist beliefs were not theoretical. If they believed in talking trees, it is because the trees spoke to them. If they believed in intelligent animals, it is because animals taught them medicine or showed them the way to good water and nourishing food. And if they believed in a god or spirit, it is because that god or spirit affected their lives in concrete ways. As for that which is beyond our ken, if they considered it at all, they considered it Mystery and left it well enough alone.
Monotheistic big “G” Gods were not part of any traditional animist cultures of which I am aware. The so-called “Great Spirit” of the North American Indians, so quickly embraced by the invading Europeans as corresponding to their own monogod, was a creator or father-sky god. He was more like the Creator of my pantheon than the one-and-only monogod of the Christians.* Some folks believe that the Indian Great Spirit corresponds to an abstract life force, or the Spirit-That-Animates-All-Things of which today’s agnostics are so fond, but I would suggest that the animating spirit was so fundamental to American Indian thinking as to be taken for granted. The concept would not need articulation in the form of a god. Animism was apparent to American Indians in the same way that the linear progression of time is apparent in our culture today.
Monotheism, although a choice for today’s animist, is an unlikely choice. Belief in the spirit and intelligence of all being makes possible the existence of intelligent beings at all levels, both lesser and greater than human. If a rock is alive, how great must the mountain be! How great the galaxy! If one may talk to bear or deer, it’s just as likely to talk with Sun or Moon, or with some greater-than-human being like my Charlie or the Place Beings of the Australian indigenous folks or the Athena of the Greeks. The animists of my acquaintance are polytheists of one kind or another, believing in small “g” gods, but not in a one-and-only big “G” God. Or they are not “theists” at all, but see and communicate with other kinds of greater-than-human beings.
I don't think one can be animist and humanist at the same time, without a belief in any gods or intelligent nonhumans. How could the universe be pulsing with life and still find itself intelligence-impoverished, with puny humanity as its highest and most sublime expression? Besides, when you are open to the voices of the nonhumans, the greater-than-humans will speak to you. This leaves humanists who say they have an animist vision in an uncomfortable and untenable position. Either the humanism will have to go, or the voices will have to go, leaving them in a quietly lonely world.
* My opinion here. I have no references for you.