Necessity...

...knows no law:

Two fishermen lost in Siberia are suspected of killing and eating their friend in order to survive, it was claimed last night.

A fourth man is also missing, leading to fears that he, too, was murdered and cannibalised.

Shipwrecked sailors faced this horrible dilemma often enough that it came to be codified as The Custom of the Sea, although that didn't mean that those who resorted to it were free from legal consequences.

So, think about it: lost in Siberia for three months in winter, and the rations run out after the first week, or month...what would you do?