Full Rut Flehmen Response: What It Is and What It Means
Introduction to the Flehmen Response Across Wildlife Species
Have you ever seen a white-tailed deer buck chasing a doe, or a bull elk pushing around his harem of cows, or a bighorn ram sniff the urine of a ewe? You’ll often see them stop and make a similar face across species and then get a sudden burst of energy with a focusing interest in the females. This wide-eyed smiling appearance erupts when the male’s upper lip curls up as he inhales through his mouth. This is the Flehmen response, sometimes called the Flehmen posture. But what exactly is it and what does it mean?
What is the Flehmen Response and How Does it Work?
Asking the question– “What is the Flehmen response?”– is basically asking– “What is the rut?”– because they are so intertwined. The Flehmen response is a physiological process by which an animal smells pheromones and hormones, causing the animal’s upper lip to curl up while orally inhaling to funnel air filled with pheromones and hormones to the vomeronasal organ, otherwise known as the Jacobson organ. The Jacobson organ is a sensory organ located in the roof of the mouth near the throat. Both male and females can exhibit Flehmen behavior but it is much more common among males, especially among hooved species. When a female is hot (in estrus), she releases hormones and pheromones that indicate she is ready for breeding from her genetalia, feces, urine, and other excretory pathways. These pheromones and hormones are interpreted by the male’s Jacobson organ, which then triggers the males libido (male sexual reproductive drive). The burst of energy that follows the Flehmen response is the physical manifestation of the sex drive and causes the male to seek out the female with the lone goal of reproducing offspring. This is the rut.
The Significance of the Flehmen Response for Wildlife Managers
But what does the Flehmen response mean to me as a wildlife manager or hunter? From the aspect of a wildlife manager, the Flehmen response indicates which animals in the population are actively involved in sexual competition and reproduction. It can also indicate when a subadult animal in the population is becoming sexually mature; if the urine of a young female induces a Flehmen response in a sexually mature male she may be coming into her first estrus and likewise, if a young male begins to posture the Flehmen response then he is probably entering sexually maturity.
How Hunters Can Use the Flehmen Response to Their Advantage
But how does this impact a hunter? For a hunter, the major implication of a target game animal that is showing the Flehmen response is altering the strategy of how to hunt that animal. If a hunter sees an animal in the Flehmen posture, it means that male animal is interested in one thing– reproducing offspring with whichever fine-smelling specimen caused the Flehmen response. It further means that hunting strategies which rely on feeding patterns or over bait/water will be less effective because the nutritional needs fall by the wayside of the rutting male. It also means that the normal movement patterns will go out the window and the new patterns of that male will mimic, at least for a short period, the newfound female friend.
Adjusting Hunting Strategies During the Rut
Although these factors can limit the avenues to a successful hunt, they also specify which tools and strategies will aid in success. White-tailed deer bucks will typically accompany a hot doe for about three days. This allows for multiple breeding attempts, increasing the likelihood of conception and allowing the buck to defend the doe from sexual competitors. During this time, the bucks will hang tight with the doe (following her patterns), are more likely to respond aggressively to calling and decoys, and are much less observant of surroundings. Basically, when their nose and mind are buried in the genitals of the female they’re with, it makes them easier to spot-and-stalk hunt or tempt with sexual competition.
Conclusion: The Flehmen Response and Hunting Success
Understanding the Flehmen response is an essential tool for wildlife managers and hunters alike. Whether identifying reproductive activity in the herd or adjusting hunting strategies during the rut, recognizing this behavior can make all the difference in both conservation and hunting success.
Bibliography:
Hart BL. Flehmen behavior and vomeronasal organ function. 1983. Chemical Signals in Vertebrates 3:87–103.
Gentry Jr. GT. 2019. White-tailed deer reproduction: How fawns are made. LSU Ag Center. Read More (Accessed September 8, 2024).
