Sheep might be an exageration but it would certainly take lambs. The best thing about snakes is that they keep mice and rats under control. On some parts of the coast the National Parks and Wildlife Service is reintroducing red belly black snakes for the importyant role they play in maintaining a balanced environment.
The biggest snake recorded was one trapped and shot in the Bolivian Jungle by an American pistol champion Lee Ecolls (I have the book somewhere. It was 32 ft long and as big arround the middle as a 200Lt (44gallon Aust/ 50 gal American) Drum. It would occationally drag a cow into mits lair.
One day a friend witnessed a 3 metre long lace monitor struggling with a 3 metre python in her rainforest creek. The goanna was a huge powerful beast but the Python won.
I have photos of a big lace monitor unexpectedly sneaking right up to my face while I was eating outside. I'll post them once I get my scanner fixed.
A lace monitor (big goanna)