[TOMT] [Movie] Looking for the name of a movie that I watched in the early 2000's.

I watched it with my older brother and his friends when I was younger. I'd have to estimate that it was around 03'. It was a teenage coming-of-age/drama.
The opening scene is of two male teenagers getting drunk in the middle of the night, and they're so drunk that they put a glass beer in the middle of the street, while the other teenager takes a chainsaw to a light post, where it falls directly on the glass beer. Other points I remember are of the two teens breaking into a zoo one night, which they had visited previously and observed a seemingly tame tiger/lion. As they break in, they get into the area where this supposedly tame tiger/lion lives, but unexpectedly another one appears and mauls one of the teens. The other teen then mourns pretty heavily over his lost friend, and he visits his grave quite frequently i think.

That's all the detail I know, if anyone can figure out what the movie was called, I'd be super psyched.