Dogs are known for their sense of smell and hearing. They belong to the Carnivora family, and nearly every animal belonging to this family is known for its exceptional senses. Bears, for example, can smell their prey from more than 30km away.
As far as dogs are concerned, they have an enhanced sense of smell owing to the larger surface area of their nostrils. They are capable of breathing in more air as compared to humans. Even though the distance from which they smell a particular scent is dependent on environmental conditions and the scent itself, under optimal conditions, a dog can pick a scent from 30km away.
Moving on to the hearing senses of a dog, all the muscles present in the dogs’ ears help them prick their ears and adjust them accordingly to capture every single sound wave. The audible frequency range for humans is 20Hz to 20kHz, where dogs are capable of decoding the sound waves lying between the frequency range of 70-100kHz. This is the reason that dogs are able to respond to the high-pitched dog whistle, whereas humans do not hear a thing. However, dogs are then more sensitive to loud noises such as that of a thunderstorm.
When dogs prick their ears and start moving them in a particular direction, this means that they are picking a sound source that the humans can not locate. This along with the smelling sense of the dogs makes them a great candidate for being an assistant to the people who have an impaired vision or cannot hear properly. Dogs are also used by the police to sniff out drugs, bombs, illegal imports, and suppress other criminal activities.