Flehmen Response

I actually had to look up the spelling of this because apparently, I've been spelling it wrong. Anyhow, what is flehmen response? It is the act of flehmening, and if that didn't help, let me explain further. A male animal will inhale air to detect whether a female is in heat. They do this by curling back their upper lip and revealing their teeth while inhaling pheromones and other scents through the roof of their mouths just behind the teeth. Sheep do it, goats do it, and so do horses.

Actually, as far as I'm aware, all mammals do this. When with a female, the male will repeat the flehmening behaviour repeatedly, not wanting to miss that all important heat cycle.