About The Dog: Man’s Most Useful Best Friend Yellow Magpie – About The Fascinating

About The Dog: Man’s Most Useful Best Friend

Dogs are said to be man’s best friend. It is difficult to see why not. Dogs and humans have had a close relationship for thousands of years and during that time their bonds have been strengthened. Dogs are one of the most intelligent and thoughtful animals. Because of this, they are a staple in many people’s home.

In common parlance, a male dog is simply referred to as a ‘dog’ while a female is commonly called a ‘bitch’.

Size of Dogs

Dogs (Canis lupis familiaris) come in all shapes and sizes. The smallest adult dogs can be under 10 cm (4 inches) at the shoulder and have a body length under 15 cm (6 inches). According to The Guinness Book of Records, a Yorkshire Terrier is the smallest known dog with a measurements of 6.3 cm (2.5 inches) at the shoulder and a body length of 9.5 cm (3.75 inches). Dogs’ weight are as varied as their breeds -- from less than .2 kg (8 ounces) right up to the 100 kg (200 lbs) St. Bernard.

The tallest breed of dog is the Irish Wolfhound which can be in excess of 80 cm (2.5 feet) at the shoulder. Dogs can live for up to 20 years of age. However, the average dog lives around 12 years. Contrary to popular belief, there is no such thing as dog years -- it is just an invented term. Canines, like Cats are found in most parts of the world, with the exception of Antarctica. Basically, where ever there is man -- a dog is sure to be not far away.

Domestication

There is widespread disagreement as to just how exactly dogs became tamed. There are two different competing trains of thought on the subject. Some believe that it was once-off encounter with wolves which led to their domestication. Others believe that it happened gradually and in different regions. What’s more, there is also disagreement about who initiated the first contact -- humans or wolves.

There have been suggestions that wolves gradually familiarised themselves with people as they prowled our rubbish dumps. This led to them being indifferent to humans and rendered them more susceptible to being domesticated. However, an opposing argument suggests that we adopted wolf pups. Darwin’s ‘Natural Selection’ then became apparent as those most suited for human companionship survived to become our domestic dog.

Experiment

During the 1950s, an interesting experiment by a Russian scientist took place. Dmitri Belyaev demonstrated that wild foxes could be tamed relatively quickly. In his famous experiment, Silver Foxes (Vulpes vulpes) essentially became domesticated dogs after only 20 years of intensive breeding. The foxes were completely at ease in human company and displayed dog-like behaviour by wagging their tails and licking people. Even more startling than the behavioural changes, was the fact that they developed floppy ears, curled tails and spotted coats. This was completely different than their wild counterparts.

However dogs become tame, DNA evidence has shown that dogs evolved from the Grey Wolf (Canis lupus) approximately 15,000 years ago. It is estimated that they were subsequently kept by humans somewhere between 12,ooo and 14,000 years ago. Dogs quickly travelled where ever their human compatriots went.

Invaluable

They were an incredibly important asset to man. As well as assisting in hunting and providing food, they would provide protection from dangerous predators. In terms of transportation, sled dogs assisted in transversing some of the most difficult of terrains.

In more recent times, dogs still play a very valuable role in society. They aid in animal herding and provide protection and security. They act as drug detectors and assist the blind and physically disabled.

One of the most remarkable aspects of dogs is their olfactory capacity. A dog’s sense of smell is immeasurably better than a human’s. On a quantifiable level, a dog possesses over 200 million olfactory cells while we only have a paltry five million. According to the Sensory Research Institute at Florida State University, a dog’s sense of smell is on average 10,000 to 100,000 times better than humans. Even the best odour detecting machines are greatly outperformed by dogs.

Cancer Detection

According to the Pine Street Foundation, a cancer research organisation in San Anselmo, California, dogs can accurately detect if people have cancer or not by smelling the person’s breath. In a study carried out on breast and lung cancer, it was found that dogs can detect cancer with an accuracy of between 88% and 97% depending on the type of cancer. They have close to a 99% success level with lung cancer patients. These results are higher than current cancer screening techniques such as mammograms and CT scans.

In fact, dogs can be trained to find most objects by smell. Currently dogs are used to detect drugs, landmines, dead bodies, and even smuggled goods.

There are currently, approximately, 400 million dogs in the world. This number is comprised of just under 400 different breeds. However, it must be noted that, although dogs have been domesticated, nearly 14,000 years ago, they can still inter-breed. Therefore, ignoring birthing and mating difficulties, a tiny Chihuahua could theoretically produce a pup with a Great Dane.

The huge amount of different breeds is due to humans picking inherited traits which are valued more above others. Many of these traits would make dogs impotent in the wild. For instance, it is highly unlikely that a tiny Yorkshire Terrier or a Papillion would survive without a owner to look after it. Another problem with aggressive breeding programmes is that pure-breds suffer more diseases and genetic disorders than mongrels.