Who Has The Most Taste Buds?
Dogs and cats both have superior vision and a superior ability to hear when compared to us humans. But who wins the battle when it comes to the sense of taste? Well just as smell depends on the number of olfactory receptors taste depends on the number and type of taste receptors that are found on our tongues, and as it turns out, not only do our pets see and hear our world differently than we do, they taste differently as well. All vertebrates have a tongue, but the number of taste receptors (taste buds) vary significantly. Birds have as few as 30 taste buds, where as our feline family members have about 470 and our dogs, with a slightly more sophisticated palate, have 1700 taste buds. (Though I must question Fraser Valley Animal Hospital’s official greeter’s taste buds, for anyone who knows Winston knows that this boy eats everything and taste is not a deciding factor). The winner, though, of this taste bud race belongs to us humans with a grand total around 9000 taste buds. (Truth be told, it is actually the herbivores, like our pigs and cows who win this race with a whooping 14,000 and 25,000 taste buds respectively).
WHAT DO TASTE BUDS TASTE…do we taste the same?
Just as vision and hearing are important for survival in the wild, so is taste. A basic rule of thumb is that if something taste good then our body needs it and it is a useful and digestible object, where as something that is poisonous and harmful to our bodies will taste badly. Since a dog’s, cat’s and human’s nutritional requirement varies, so do the taste buds on our tongues.
Dogs and cats both have a diet that contains a high percentage of meat, and as meat already contains a high sodium content, they do not have a strong craving for salt or highly tuned salt receptors. Where as us humans and herbivores do have a strong taste response to salt, as it is needed to balance our diet, as vegetables and grains naturally contain low sodium levels.
Since our dogs and cats do consume a diet that is high in sodium they also have developed taste receptors that we do not have, namely water taste buds.
It is thought that this taste receptor evolved as these animals needed to be able to produce more urine after consuming a sodium rich meal in order to keep their electrolytes and bodily fluids in balance.
Another difference is the ability to taste sweet, which both humans and dogs share, but cats are unable to do. Sweetness is associated with carbohydrates and thus an important food source for any animal that consumes plant. Cats being a strict carnivore do not need sweet receptors for survival. But cats have also developed a receptor to be able to taste ATP (adenosine triphosphate), which is a compound that supplies energy to every living cell and is present in meat.
The ability to taste bitter is a very sensitive receptor as bitter is a sign that something is bad, such as rancid meat, and thus dogs, cats and humans have this ability to taste bitter. So we employ bitter sprays to cover bandages, wounds, or furniture to help keep our dogs from licking or chewing. The interesting thing is that the bitter receptors are found on the back of the tongue. This means with a quick lick or fast gulp the receptors will not pick up the bitter taste, and it is only after prolong chewing that the brain register the bitter taste. One would think that since this receptor is so important in preventing the ingestion of toxins, it would have been placed on the tip of the tongue.
After being a veterinarian for 24 year and especially, after owning Winston the pug, I greatly question many dog’s taste buds after the things I have seen them eat!
To learn more about the sense of taste check out this interesting kids video from the 80’s, guessing by the fridge in the background.