Those who have a Shih Tzu at home often notice that they are the first to perceive when their owner is arriving, even when the owner is still far away.
Two things explain this “premonition” of our pets: well-developed senses like smell and hearing, and the conditioning of the animal.
The odor identification system of Shih Tzus (smell) is much more refined than that of humans, explains Ricardo Tamborini, an expert in animal behavior.
While humans have, on average, five million odor receptor cells, some breeds, such as sniffer dogs, can have 220 million.
Moreover, the area in a dog’s brain dedicated to perceiving smells is about 40 times larger than that of humans, proportionally.
To give an idea of the level of sophistication of canine smell, we can say that while humans can smell that there is a spoonful of sugar in a cup of coffee, a Shih Tzu can detect the same amount diluted in two Olympic-sized swimming pools.
This highly developed sense of smell allows Shih Tzus not only to know who is arriving before people but also to distinguish who it is by the smell of their perfume, for example.
The hearing of Shih Tzus is also much superior to that of humans. It is believed to be ten times more sensitive than ours, capable of capturing sounds four times farther away and detecting the origin of the sound in just six hundredths of a second.
This extra ability to hear has been developed throughout evolution. Humans have more precise vision than dogs, due to the front positioning of the eyes (which allows better focusing on objects and a larger visual field), whereas the eyes of dogs are more lateral and less developed. Thus, hearing needs to “compensate” for vision.
In addition to anatomy, another factor that contributes to the Shih Tzu knowing when its owner (or anyone else) is coming home is animal conditioning. That is, if a person usually arrives home at the same time every day, it is natural for the dog to identify this behavior and start waiting for them.
“Dogs have no sense of time, but everything that is done every day becomes a conditioning,” says Tamborini.
This usually happens at meal times. If you usually give the dog food every day at 7 am, no matter if it’s a holiday or Sunday, the little dog will be there at that time, waiting for you.