A few weeks ago I spotted a minor buck – a meager example of a four pointer (actually a three and a half pointer) – approach a small herd of does in a field south of West Branch, MI. The sun was setting and the fellow obviously had high hopes for a wild party night. The big bucks were elsewhere and he was performing a bit of Cervid Carpe Diem. Unfortunately, the gals were not about to allow him to seize their day, or night, for that matter. One by one they scooted away as he approached.
My intention here is not to document the exploits of a frustrated buck and risk embarrassing him back at the dork buck club. Rather, I’d like to focus on one aspect of his behavior called the Flehmen response. Our minor buck frequently stopped to smell the “Eau de Doe” in order to determine the reproductive status of the females surrounding him. He lifted his head up, curled his upper lip into what could be described as an open-mouthed sneer, and held that pose for extended period. He was processing the air-borne pheromones which charged the air with sexual energy.
It is not enough to just sniff the air through the nostrils to detect pheromones. The Flehman response allows for a direct shot of scent laden air to enter the vomeronasal organ (aka Jacobson’s Organ) located between the upper palette and the nasal opening. The nostril openings are closed during this action and the air stream enters via a pair of openings located on the roof of the mouth just behind the lips. Sensory endings in the Jacobson’s Organ are quick to read the phermonal message and relay the information to the buck’s brain. It conveys either a green light or a stop sign for the buck’s aspirations.
All manner of mammals, from cats to horses, perform the Flehman response. In fact, if you have a few minutes and are looking for a laugh, just Google the term “flehman” and you will get a flood of ridiculous smiling horse pictures. A flehmening buck lacks the upper row of front teeth found on horses, so their appearance is slightly less cheesy looking but presents an equaling interesting picture.