I got about 19% through before giving up.
The Bear is told through the narrative voice of a five-year-old girl. It's a very stream-of-consciousness, go-off-on-a-tangent sort of voice, which may or may not be a convincing literary device in a novel told through the eyes of a child. However, this is a novel told through the eyes of a child whose parents are being attacked and eaten by a bear. (And later, presumably, a child fleeing through the woods with her toddler brother: by the time I gave up, one parent had been partially eaten and dismembered; the other was merely paralysed through a broken neck and gravely injured / not quite eaten yet). In that context, the writing voice simply does not fit, or convince.
At one point, the children are inside an empty cooler box, which is semi-locked (a rock features in some way to keep the door slightly ajar, while it is locked enough to prevent access). The bear gets interested. It tries to open the door with its teeth, with its nose and teeth protruding inside. Scared of the "big dog" and its long, long teeth, the girl nevertheless compares the shine of the black nose to the leather on her grandpa's sofa. If it was a throwaway remark / description, that might still just about work, but then we get a page-long memory of her grandfather and his TV/sofa habits, WHILE A HUNGRY BEAR WITH BLOODY SNOUT IS GNAWING AT THE DOOR to the cooler she is in. Even the most scatterbrained, short-attention-spanned child would not, in my opinion, get distracted from a hungry mouth full of scary teeth trying to get at her.
As far as I read, the book relies heavily on the sheer drawn out horror of events - and the fact that the children are unaware of what is really going on, but have a sense that something is very wrong. The horror is visceral, complete with extensive feeding noises, dismemberment, screams, etc. - imagining a toddler and a five-year-old in that context is brutal. However, the narrative voice ruins it by being ridiculous and unconvincing. Not that it would be a joyful reading experience if it were more authentic: some horrors are too gruesome to make enjoyable entertainment, especially as the foreword points out that the details of the bear attack are an account of a real incident. Basically, much of this book is not just torture-porn, but snuff literature. It's hard to see it as being anything but a badly written book, in very poor taste.
Really not recommended at all.