Yes, be, in any of its conjugations, can mean exist. To quote the OED:
be (verb) I.1.a: to have place in the objective universe or realm of fact, to exist; (spec. of God, etc.) to exist independently of other beings. Also: to exist in life, to live.
However, your sentence sounds unnatural to me. At least in my experience, the use of be as above often connotes a degree of solemnity. Consider the examples given in the OED:
The great beasts came first, strange forms that were when the world was new. (E. Nesbit)
To be, or not to be, that is the question. (Shakespeare)
God is, nay alone is. (Thomas Carlyle)
These examples all deal with remarkable topics: dragons, human existence, and God! For a more down-to-earth topic, like types of beavers, I would instead use the following.
There are two types of beavers.