Dogs sniff to identify, for the majority of cases it is to sniff whether or not there is danger. A dogs sense of smell is much greater than that of a human being and it can smell things from a further away distance than many other animals as well as humans. But when a dog can smell something that it associates with danger it enables the dog to avoid the smell. But that is one of the main reasons behind why dogs sniff, but there are other reasons also which will be discussed now.
One reason as to why dogs sniff is so that they can identify the food that is in front of them, though it is a similar reason to the one discussed above it does have different properties involved. Dogs want to be sure that the food they are eating is safe and appropriate; they have to be suspicious before eating and by inspecting it enables them to determine whether or not they should eat the food. Of course it can be applied differently, a dog may sniff food to check whether or not it is a food they like, and if they do not like it they can not eat it.
A common scenario that I am sure we are all familiar with is when you go to a friends house, they have a dog and their dog will be suspicious around you and will sniff you. You will notice that it will sniff you and observe you for a while and after it has identified you it will leave you alone and be at ease. But this is typical in a dogs nature, it will sniff you because it has to be sure that you are not a threat to it. A dog like other animals and use as humans like to feel safe and since a dog has such a good sense of smell it gives it a unique advantage, a dog can sniff its surroundings and identify whether or not anything is dangerous or a threat to it. By using this it enables the dog to feel safe and not on edge, this is why you will often find that dogs will sniff you for a while, and once they have identified you as not being a threat they will simply move on and act like you are part of the background.
Sniffing is an excellent way for a dog to sniff out any abnormalities, if anything out of the ordinary pops up the dog can simply scan the object using its advanced sniffing sense and then label it either dangerous or safe, and if it is safe it will simply blend into the safe environment that the dog sees. Dogs will always sniff for a main reason because they want to make sure that they are safe and not at risk, by sniffing they can identify whether or not something is a threat, of course it does not apply all the time to every threat, but it can help. This is why you will see many sniffer dogs in the police force; they have an advanced sense of smell which can sniff out any dangerous substances etc.
But the dog primarily sniffs so that it can identify the particular smell, once doing so it enables the dog to determine whether or not the smell is a threat. By using the advanced sense of smell the dog can move away from any dangerous situation before anybody else would even know. With this unique sense of smell the dog is able to sense danger from a much further distance away. Of course a dog does not just use its sense of smell to sense danger, but also to identify objects such as food. There are many reasons as to why dogs sniff, but the primary reason is so that it can identify whatever it is smelling.
I hope that this article has offered you some good information as to why dogs sniff. Now that you know some of the reasons as to why a dog sniffs you should hopefully be equipped with knowledge of the subject. Always remember that the main use of sniffing is to identify.