A dog's sense of hearing

Dogs have a superior sense of hearing when compared to humans and can hear a range of sounds far above the capabilities of the human ear. Dogs can hear sound frequencies up to an amazing 45,000 Hz whilst us mear humans can only manage 23,000 Hz.

Selective breeding over the centuries has further enhanced the sense of hearing in certain breeds and has helped them to perform specialised tasks, such as guarding flocks, flushing out game and protecting property.

A dog's sense of taste

Taste is a very old sense in evolutionary terms. Sensations of pleasure and revulsion provided by taste serve as a survival function. A reasonable rule of thumb, at least for natural substances is that bad tastes are a signal that the animal has encountered something that is potentially harmful, indigestible, or poisonous, while good tastes signal useful, digestible, edible  substances.

Because it is important for survival, it is not surprising to find that taste is one of the earliest senses to begin functioning in dogs.