The sense of smell is a powerful tool in the animal world and one which has been systematically honed in the canine world by selective breeding to such an extent that there exists a whole classification of scent hounds. Even the lowliest mongrel has a capability that far exceeds that of his human master, thanks to many more scent receptors in the canine nose. The human has approximately 5 million receptors whilst the dog has between 125 million (Dachshund) and 300 million (Bloodhound).
Scent also plays a part in the messaging system of the dog helping to provide information on the age, sex and health of an individual, information which can be left behind in the environment until it finally decays. For this reason the dog never completely empties its bladder leaving sufficient urine to mark the next lamppost or tree at a convenient height for the next canine nose that comes along, hence the dog cocking his leg. Nature has also provided the anal glands under the tail so that further information can be contained in and on the droppings. Scent also informs the greeting rituals between dogs especially the “dance” between male dogs ,where each dogs attempts to smell the rear of the other without allowing the other the same opportunity. If information is power then there is an advantage to smell the anal glands of the other dog and establish its health status etc.without revealing any of your own information.
Conversely pups will dribble small amounts of urine in a supine position in order to allow the adult to smell that they are no threat.
In the human –canine world this can lead to mixed messaging especially in the field of toilet training where owners attempt to mask odours often without success, or worse clean with bleach which mimics the urine smell of a strange dog, causing the dog to over-mark this new message. As dogs will over-mark another dog’s scent six times more often than they do their own, it is no wonder that inexperienced owners become frustrated with failed attempts at toilet training when the dog returns to urinate in the recently cleaned spot. Owners can then become annoyed and yell at the pup which then attempts to appease the owner as it would do to an adult dog by dribbling urine which then annoys, if not infuriates, the owner resulting in a cycle of submissive urination.
Scent discrimination is an attribute which can be trained so that the dog can identify specific chemical signatures be they truffles, drugs, explosives,bodies or currency. Not much call for that in the home you may think but it can save a lot of heartache if the dog can discriminate its toys (covered in cheap perfume) from those unscented playthings of the child or baby with which it lives. Unfortunately inadvertently learnt scent discrimination leads to problems when the puppy is given an owners old shoe to chew and then naturally presumes all things that smell the same are appropriate chew toys: mobile phones, wallets, remote controls etc ,all of which have been handled by the owner. The scent discrimination also accounts for the dog which lies or worse urinates on the bed or chair of its “best friend”: the mattress absorbs your smell as you lie in it and it becomes concentrated essence of “you” which then provides a comfort zone for the anxious or distressed dog reinforced by the dog adding its own scent signature.
In the recent days we have become accustomed to the role of dogs used in scenes of disasters, searching for survivors in the ruins of buildings following earthquakes, typhoons, floods or building collapses. Flown into disaster areas these dogs help locate the trapped and buried using their keen sense of smell and discriminatory training to save lives. Cadaver dogs are then used to find the bodies of those unfortunates who do not survive .
However, have you considered the other dogs in disaster zones ? The ones that are native to the area that have lost their homes and human companions? During the aftermath of Hurricane Katrina which struck New Orleans thousands of dogs were abandoned or separated from their owners or were left roaming the streets. The American SPCA now has a checklist for pet owners facing natural disasters to ensure the safe evacuation and ongoing care of family pets. Recently the tragedy in the Philippines has affected those pets that survived being put up for adoption after their owners have been made homeless.( http://www.mb.com.ph/super-dogs-survive-super-typhoon/)
Other areas of the world are not so lucky and rely upon the charities for help with their problems.In the aftermath of the Boxing Day tsunami many thousands of dogs were killed by the authorities who misunderstood the “normal” aggressive warnings of dogs protecting their young or resource guarding. as a sign of rabies. Such killings continued until the intervention of volunteers and welfare agencies began to educate and change the authorities’ opinions.