PHUKET: DOGS inherited their keen senses from wolf ancestors, and it’s these attributes that enable dogs to play a massive part in our lives. With their phenomenal sense of smell, dogs are being used to sniff out illegal narcotics, explosives and even pirated DVDs.
Their sight and hearing capabilities help assist the blind and deaf to live more independent lives, while their strength and stamina make them ideal for both water and mountain search and rescue operations.
A DOG’S world is almost entirely oriented by smell. Their incredible scent-detecting powers are so superior to ours that it’s almost incomprehensible. Dogs are able to detect scents at such low levels that even computers can’t detect. Humans have around 5 million scent receptor cells in our noses, compared to around 300 million in dogs. Additionally, due to the structure of their noses, they can breathe in a scent and keep it in their nose – while still managing to breathe in and out.
Dogs’ noses are also famously wet, and with good reason. Numerous tear ducts run all the way down to the end of their noses as a wet nose allows them to detect the direction of the wind and thus sniff out scents carried in the breeze.
The moisture also helps to dissolve scent molecules so receptor cells located in the nose can identify specific odors. This is why dogs are able to pick out the tiniest trace of contraband amongst a host of “decoy” scents such as coffee beans.
THE SOUND OF SILENCE
DOGS hear far better than humans. They hear sounds over a greater range of frequencies; they hear sounds from much further away and can pinpoint the origins of these sounds with exceptional accuracy. For example, a sound we hear at 20 meters, a dog can detect at 200m.
Dogs also have movable ears, which enables them to localize sounds accurately and quickly – in about one 600th of a second to be precise. To ensure the dog knows from which direction and where a sound is coming from, there are more than 18 separate muscles in their ears which pivot, tilt, elevate or lower the ear.
Dogs can detect sounds as low as 67 Hz – the equivalent of thunder rumbling in the distance – much the same as we can. However, their high frequency hearing is far superior and extends as far as 45,000 Hz, which is 10 times higher than the highest C note a Soprano can sing. Such sensitive hearing means that while dogs are sleeping, they are able to detect sounds inaudible to us.
SEEING IS BELIEVING
A DOG’S sense of sight is very different from ours. Our vision is binocular and forward directed, whereas a dog’s is more monocular and peripheral, allowing them to detect the slightest movements, even when they’re coming from behind.
Humans’ eyes are located at the front of the head, giving us a field of vision just over 180 degrees, but we have to turn our heads if we want to see things to the side or behind us. With dogs, the positioning of the eyes on the side of their heads gives them a field of vision in the range of 260 degrees.
A dog’s vision in dim light excels, to the point that a dog can see an object at a light threshold one sixth of what a human needs to see the same thing. While dogs are not color blind, they don’t have such an acute sense of color as we do and find it difficult to differentiate between red and green.
Dog Whisperer is Phuket Gazette columnist Russell D Russell’s feature series covering all things special about our four-legged friends.
Russell D Russell IACP, ADPT, UKCBC is a professional canine trainer and behaviour specialist. He can be contacted through w.tk9a.com
— Russell D Russell