Nicolas Mathevon knows what boils a crocodile’s blood. In Guyana in 2007, when Mathevon played a recording of an infant croc distress call, a bellowing mama croc lunged at the boat he was in.

They display dominance by hissing, bellowing and slapping the water with their tails to communicate. During the nesting season, a mother Nile crocodile deposits her eggs in carefully dug nests ...