Wolves Don't Prey on Wolves

Two wolves in lawyer’s robes are congratulating each other in front of an eating place serving cold food.

The caption reads in the original French: Les loups ne se mangent pas. This proverb doesn’t seem to have any satisfactory equivalent in English. It is used to signify that members of a given group will readily attack weaker victims but won’t try to harm each other, in said group’s best interest.