Vomeronasal Organ - Animals

Animals

The functional vomeronasal system is found in many animals, including all snakes, and lizards, plus many mammals, such as mice, rats, elephants, cattle, dogs, cats, goats, and pigs.

• Salamanders perform a nose tapping behavior to supposedly activate their VNO.
• Snakes use this organ to sense prey, sticking their tongue out to gather scents and touching it to the opening of the organ when the tongue is retracted.
• The organ is well developed in strepsirrhine primates such as lemurs and lorises, developed to varying degrees in New World monkeys, and underdeveloped in Old World Monkeys and apes.
• Elephants transfer chemosensory stimuli to the vomeronasal opening in the roof of their mouths using the prehensile structure, sometimes called a "finger", at the tips of their trunks.
• Painted Turtles use this organ to use their sense of smell underwater.

In some other mammals, the entire organ contracts or pumps in order to draw in the scents.

Some mammals, particularly felids and ungulates, use a distinctive facial movement called the flehmen response to direct inhaled compounds to this organ. The animal will lift its head after finding the odorant, wrinkle its nose while lifting its lips, and cease to breathe momentarily. Flehmen behavior is associated with “anatomical specialization”, and animals that present flehmen behavior have incisive papilla and ducts, which connect the oral cavity to the VNO, that are found behind their teeth. However, horses are the exception, they exhibit Flehmen response but do not have an incisive duct communication between the nasal and the oral cavity.

• House cats often may be seen making this grimace when examining a scent that interests them.