The dog’s nose knows
PET BULLETIN
‘Mews and Yips’ from the Central Aroostook Humane Society
By Allen Salo
Board Member
I have always been fascinated by the olfactory (smelling) abilities of dogs and I’m sure many of you are aware of some of the ways those abilities have been put to use to benefit people in some manner.
This article is intended to briefly characterize the far superior olfactory ability of dogs — that is compared to the ability in people — and to characterize some of the classic as well as newer ways we are able to harness this incredible ability of our canine friends.
Randy Kidd, DVM, provides a short introduction to this topic (cited below) in which he reports that dogs have approximately 125 million to several times that number of unique olfactory receptor cells that line the interior portion of their nasal cavity. Interestingly, the number of receptors varies based on breed, with some of the highest numbers found in Bloodhounds and German Shepherds — perhaps this is not too surprising based on the well-known use of these breeds to find missing or escaped persons or other substances such as bombs.
The olfactory cells of dogs are much greater in number than cells in the nasal cavities of humans: 5-10 million cell range. Furthermore, the amount of brain tissue that appears devoted to processing the messages carried by these cells to the brain is also notably larger in dogs than humans: perhaps as much as one-third of the dog’s brain may be involved with interpreting such information.
The upshot of these anatomical differences suggests that dogs may have the ability to be a thousand to perhaps millions of times more sensitive to odors than are people. Think of that next time you are grilling burgers!
Although space does not allow an exhaustive list of the uses for which we have taken advantage of dogs’ olfactory abilities, a brief list is noteworthy. It’s been estimated that we have used dogs as hunting companions, dating to some 12,000 years ago, and since the 1800s at least as trackers of humans (Lorenzo et al, 2003). This same source indicates a variety of ways we have used dogs, including such unique detection capabilities ranging from abalone detectors (an endangered mollusk that is sometimes poached) to finding currency (money), gold ore, rotten power poles, termites, and even truffles! Obviously nearly anything with a unique smell could, in theory, be used to train dogs to alert to uniquely.
Perhaps some of the most significant targets that many have heard about is dogs’ ability to detect various forms of cancers, including those of bladder, breast, lung, ovarian, prostate and skin (melanoma; Moser et al, 2010). Common sources for these have included samples of an individual’s breath, urine, tissue samples or covered lesion areas on the skin.
It seems likely we will continue to learn to take advantage of this remarkable ability of dogs to smell certain aspects of our worlds.
Do remember that the Central Aroostook Humane Society is open Tuesday through Saturday, 10 a.m. to 4 p.m., closing for lunch from noon to 12:30 p.m. Donations and visits with the animals are always welcome. Several cats and kittens (as well as some dogs) are waiting adoption.
References:
• Kidd, Randy. The Canine Sense of Smell, obtained from: www.whole-dog-journal.com/issues/7_11/features/Canine-Sense-of-Smell_15668-1.html.
• Lorenzo, N., Wan, T, Harper, R., Hsu, Y., Chow, M, Rose, S., Furton, K. (2003). Laboratory and field experiments used to identify Canis lupus var. familiarisactive odor signature chemicals from drugs, explosives, and humans. Anal Bioanal Chem, 376, 1212-1224.
• Moser, E., Mcculloch, M. (2010). Canine scent detection of human cancers: A review of methods and accuracy. Journal of Veterinary Behavior, 5, 145 – 152.
