Dogs can smell human fingerprints that are a week old. Their noses are so sensitive that they can even smell electricity. While conducting an experiment, a researcher found that a dog could smell which of two boxes contained an electric current.
He concluded this was because the charge resulted in the release of tiny amounts of ozone that the dog could detect. The source of the dog's exceptional ability to smell is its wet snout.
The moist leathery surface acts like Velcro, catching even the tiniest molecules of smells, then dissolving them so that the dog's internal smell-receptor cells can analyse them properly. To keep its nose wet, a dog must produce a constant supply of mucus through the nasal cavities. Scientists reckon the average dog produces a pint of this mucus every day.
Dogs prefer Bach to Britney. A study looked at the way hundreds of distressed rescue dogs reacted to different kinds of music. The sound of human voices and pop music by artists like Britney Spears did nothing to calm the stressed dogs. Heavy metal and grunge music made the dogs even more agitated. When the band Metallica were played, for instance, the dogs started barking loudly.
At the other end of the scale, however, the scientists discovered that dogs relaxed and enjoyed themselves most when they were played classical music. Naturally, they liked the sound of Bach in particular.
Male dogs tend to be left-pawed, while females favour their front right paw. Cats, on the other hand, are generally left-pawed. Studies found that 20 per cent of cats favoured their right paws when carrying out complicated, manipulatory tasks such as toying with objects, while a little over 38 per cent favoured their left. The remaining 42 per cent were ambidextrous.
Many owners think their cat senses their arrival home in the car: The truth is more likely to be that its ultrasonic hearing allows it to recognise the signature high-frequency sound of the owner's car well in advance of its arrival within human earshot.
The ten brightest breeds of dog (ranked according to their ability to understand new commands in fewer than five repetitions and to obey first commands 95 per cent of the time or better) are: 1 Border Collie; 2 Poodle; 3 German Shepherd; 4 Golden Retriever; 5 Doberman Pinscher; 6 Shetland Sheepdog; 7 Labrador Retriever; 8 Papillon; 9 Rottweiler; 10 Australian Cattle Dog.