A bighorn ram with a full horn curl lifts his upper lip to scoop pheromones in the air into his nostrils. Light snow is falling, and the area around him is covered in snow.

Have you ever caught a glimpse of your crush and had an uncontrollable smirk come across your face? You’re not alone—ungulates smirk around their crushes too. Males curl up their upper lip and expose their front gum line; this is known as the flehmen response. This goofy smirk allows pheromones that the female emits in the air to enter the vomeronasal organ, which is a very sensitive smelling organ located through a duct above the roof of the mouth. This lip curl helps all male ungulates determine the reproductive status of females during the rut. Next time you see someone smirking your way, be glad they are not going into a full flehmen response.

Description by Brittany Wagler. Image by Tayler LaSharr.
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