It is generally recognized that humans have 5 basic senses (sight, smell, hearing, touch and taste), as do dogs, but how do they compare?
- Sight: this is an interesting comparison as humans, unless they are colour blind, can see the full spectrum of colours whereas a dog can only see in shades of black and white and in shades of blues and yellows. However, dogs can see better at dawn and dusk than humans, whereas humans can see objects at a distance much better than dogs. Humans can also see things better close up than dogs. But when it comes to recognition of moving objects, dogs do have the advantage, giving them better ability to spot and hunt prey.
- Smell: this one is definitely where dogs reign supreme over humans. Even though a dog’s brain can be one tenth the size of a human’s brain, the part that controls smell is 40 times larger than in humans. A human has about 5 million scent glands whereas dogs have 125 million to 300 million (depending on breed), meaning their sense of smell is 1,000 to 10,000,000 times better than humans.
- Hearing: By the time their sense of hearing has developed (dogs are born deaf and cannot hear until they are 21 days old), dogs can hear 4 times the distance of a human with normal hearing. Dogs can hear higher pitched sounds and can detect a frequency range of 67-45,000 Hz, compared to a human range of 64-23,000 Hz. Also, dogs have 18 muscles in their ears allowing them to move the ears in the direction of the sound to further aid their sense of hearing.
- Taste: this is one of the senses where humans rate higher than dogs, with around 9,000 taste buds compared to a dog having around 1,700. Dr Stanley Coren (PhD, DSc, RSC) writing in “Psychology Today” states that the four basic taste sensations (sweet, salty, sour and bitter) apply to dogs as much as humans. However, there is one clear difference and that has to do with the taste of salt. Humans, and many other mammals, have a strong taste response to salt. We seek it out, and like it on our food. Salt is needed to balance our diet and there is not much of it to be found in vegetables and grains. Dogs, however, are primarily carnivores and in the wild, most of their food is meat. Because of the high sodium content in meat, the wild ancestors of dogs already had a sufficient amount of salt in their diet and did not develop a human’s highly tuned salt receptors and the strong craving for salt.
- Touch: A dog’s sense of touch is highly refined and mirrors humans’ sense of touch in many ways. Of the five senses that dogs and humans possess, touch is the most similar.
So having taken a look at the comparison between humans’ and dogs’ senses, I’ll be taking a deeper dive into the senses in coming weeks.