The olfactory lobe in a dog is, proportionately, 40 times larger than a person's, and some estimates suggest it may occupy up to a third of the brain's work. Additionally, a dog also has a unique olfactory organ: the vomeronasal or Jacobson's organ. This organ, located at the bottom of the dog's nasal passage, picks out pheromones, or body scents useful to mating, in the air using receptors that are distinct from those elsewhere in the nose. Finally, while humans breathe in and out through the same passageway, diluting scents, a dog exhales through the slits on the sides of its nose, leaving scents at full power for longer and stirring the air coming into the nose in such a way as to magnify odor potency.
This also lets a dog keep sniffing without the need to stop to exhale. Under perfect conditions, they have been reported to smell objects or people as far as 20km away. You might be interested to know dogs are not the only great smellers. The scientific family dogs belong to is Carnivora. This includes cats, bears and skunks. These animals have incredible senses of smell as well.
Bears have some of the best senses of smell in the family. Polar bears can smell seals , which they hunt, from more than 30km away.
This amazing sense of smell means dogs have some of the most interesting jobs of any animal: the detection dog. Detection dogs help search and rescue organisations to find missing people, look for dangerous materials such as drugs and bombs, illegal imports at airports, and help find wild animals. Now we know dogs can smell lots of things from far away, what about their hearing?
What can dogs hear, and from how far? To find out, first we have to talk about what dogs and all animals including us hear: sound frequencies. Sounds have waves. The frequency of sound is how close together the sound waves are. After all, it's much larger than the same bulb in a mouse or rat, two animals that are considered to be strong smellers. Adding to the intrigue is the fact that the number of neurons found in those olfactory bulbs is remarkably consistent across mammals, McGann reports.
Among a group of mammals with an fold range in body weight—from the tiny mouse to a male human—the number of olfactory bulb neurons changes by only fold. Human females, interestingly, have more neurons than a mouse or hamster but less than a macaque monkey.
Human males have slightly fewer. It's not clear what it means, but it's fascinating that it's true. I don't want to imply that humans would have a sense of smell that's as good as a dog in general, but there are certain substances to which we are clearly more sensitive.
Scents that humans are particularly attuned to include chemical components in bananas, flowers, blood and sometimes pee. In , Laska and colleagues tested the abilities of humans, mice and spider monkeys to detect urine odors found in common mouse predators.
While mice were best at detecting 4 of 6 distinct odors humans were actually more sensitive the other two. Humans have also been found as able as dogs and rabbits at smelling the main odorant in bananas amyl acetate , and are more sensitive to mice than at least one component odor of human blood.
These single smell studies are merely snapshots. But they suggest something tantalizing: that different species specialize in different scents that are important to their lifestyles or ecological niches. And those terrific trackers we know as Bloodhounds have million! Dogs can detect some smells in parts per trillion. You might smell chocolate chip cookies, but your dog can smell the chocolate chips, flour, eggs, and other ingredients. And when dogs sniff another dog, they smell more than doggy odor.
Dogs also have a special scent organ called the vomeronasal organ, located between the roof of the mouth and the bottom of the nasal passage.
Indeed, the smelling section of a dog brain is 40 times larger than ours. Preventing your dog from experiencing the world through scent is like putting a blindfold on a human.
The chance to smell provides your dog with important information and essential mental stimulation. They are important sources of information for your dog.
Better yet, reward short stretches of loose-leash walking or heeling with frequent sniff breaks.
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