Pigs have a sense of smell roughly 2,000 times more sensitive than humans, thanks to over 1,100 functional olfactory receptor genes.

The domestic pig (Sus scrofa domesticus) possesses one of the most advanced olfactory systems in the animal kingdom. Genetic research published in Nature reveals that pigs have approximately 1,113 functional olfactory receptor genes—significantly more than the roughly 400 found in humans and surpassing the 800 to 900 typically found in dogs.The olfactory bulb in a pig's brain is exceptionally large relative to its total brain size, allowing them to process vast arrays of chemical signals simultaneously. Their snouts are highly tactile and flexible, containing a dense network of nerves that help them pinpoint scent sources buried up to 3 feet underground.This sensitivity has made pigs invaluable for truffle hunting for centuries. In recent years, organizations like APOPO have explored using pigs and specialized rats for landmine detection, as they can identify the specific chemical signatures of TNT and other explosives even when encased in plastic or metal.Studies at the University of Illinois have demonstrated that pigs can distinguish between different odors with nearly 100 percent accuracy. Their ability to perceive scent in stereo allows them to create a mental map of their surroundings, making them among the most effective natural trackers on the planet.