Flehmen in Kangaroos

A male sniffing a female's urine to determine her sexual receptivity. He exhibits the flehmen posture, which opens up the passage to the vomernasal organ--used for detecting pheromones. Although nowhere near as distinct as in ungulates, it is still the same posture. He then shakes his head a few times to clear the excess urine and decides that she's not ready yet, and loses interest.