(I live around Australia, by the way.)

I randomly found this bone while I was on a walk with my dog. Any idea what it could come from? It's a boring neighborhood full of dogs so I doubt it's anything interesting, but I just want some clarification on:
- What type of bone it is
- What the black streaks are
- What animal it comes from
- If it's actually anything interesting.
Thanks in advance to those that take a look at it and help me out. I'm not well-versed in anatomy and skeletons in general, so excuse me if I sound dumb.