A dog's sense of taste

The sense of taste is centred on the tongue; its superficial sensory cells known as taste buds act as receptors and these are arranged in groups so differing sensations can be tasted. A dog’s sense of taste is more poorly developed compared to ours. We have about 9,000 taste buds compared to the dog which has around 1,706. Taste buds are located mainly on the tongue, they help to distinguish four qualities; sweet, sour, bitter and salt. It’s not known whether the dog’s smaller number of taste buds indicates less ability to distinguish between taste subtleties, although this is likely.

It’s also thought that dogs have additional primary taste receptors like cats, that can respond to water. This means dogs may be able to taste different types of water.

Humans and dogs palatability is very different. A human will typically resist eating something that smells bad, while dogs are the opposite, the smellier the better! Studies of dogs trained to validate specific flavours show their selections are made primarily by the sense of smell instead of taste. So, dogs are more pre-occupied with the smell of the substance than the taste of it. Typically, dogs will eat almost anything without much discrimination, as they are opportunist feeders and their survival mechanism is so great that if there’s a food source there for the taking, they’ll take it. But there is evidence to suggest dogs can distinguish taste to a degree. Studies of wolves show they can develop preferences towards certain prey and when given the choice they pick one rather than another. And, behavioural processes involved in food selection can change in response to experience. Taste buds develop before birth in some mammals - the neonate is suckled by the bitch, whose milk will vary in quality and flavour depending on what she has eaten. This means dogs that experience a number of different flavours in their early years, may accept a variety of tastes better as adults. Interestingly, taste experience in the womb has also been suggested to play a role in the establishment of taste preferences and aversions expressed after birth. (E.g.) studies show that ‘in utero’ exposure to apple solution in rats resulted in an increased preference for that flavour later in life. Similar effects were produced by odours experienced in the womb. So, it seems reasonable to assume that similar effects occur in young dogs which may represent the first stage in the development of flavour preferences.

The sense of taste also enables the body to maintain a consistent chemical balance in the body (e.g.) humans may crave a sour food such as an orange as the body may need the essential vitamins contained within that fruit. So, perhaps when a dog eats grass, his body maybe craving the necessary chemicals or fibre contained within the grass?
The study of dogs’ senses is important as it helps us understand how they communicate. While a dog’s representation of the world must be very different from ours, in essence dogs and humans are, as Protagoras the Greek puts it, “nothing but a bundle of sensations.”