There are many kinds of bears. My bear is a scientific bear; Ann's bear is very Zen (or passive, or submissive), and can be caused to loose face by the expedient of pushing on his nose till his face disappears.
Other kinds of bears can go brrr (polar bears or naked bears) or bink (mischevious bears). Holly bears (...of all the trees that are in the wood, the holly bears...) also go grr. There are no ivy bears. Compliant bears go sure; mechanical bears go whirrr.
You can always tell a bear by the fact that it cannot reach its own forehead to block binks. (Tap someone between the eyes and say "bink.")
Taurus bears say, "I said GRRR."
Gemini bears say, "Grr. Or maybe meow...?"
Leo bears say, "Grr. Do you hear me? GRRR."