If you put 10 dog owners in a room and played their dog's bark along with the other 9, chances are each person would recognise their own dog's bark.
Not only that, they would probably be able to tell if the dog was in a happy, unhappy or playful mood.
This goes to show that a dog communicates through it's bark in a number of different situations and the fact is that humans have grown to be in tune with it for just a few of those regular situations.
But what about the more complex messages. When and why do dogs bark and what is it telling us?
Well, dogs bark for many different reasons. Sometimes it can be due to separation anxiety, or seeking attention.
Other times it can be a way of greeting another dog or asking it to play. Dogs will also bark if they are alarmed or frightened by a noise or unfamiliar occurrence when they feel on guard or vulnerable.
In the most part a dog's bark is broken down into three main parts:
Depending on all three elements we can usually determine what a bark means. If it is a low pitch (like a growl) this will usually mean "stay away" but a high pitch can sometimes mean "Can I come closer" or "It is safe to approach me."
As far as duration is concerned, the longer the sound the more realistic it is to assume that the dog is very much aware of the nature of the signal and there is intent on making you understand it. It is a more serious gesture and a long, sustained growl will mean "I am going to hold my ground and I will not back down." Shorter, brief growls will more often mean that there is a little bit of uncertainly and possibly an element of fear in the dog.
The frequency measures the number of times a dog barks, so rapid barks with few spaces in between shows a fair amount of excitement and urgency. If these barks are not repeated too often and there are larges spaces in between, this will mean less excitement.
If your dog barks excessively and it is becoming a problem, then you need to change that behaviour or calm it down. It is true that some dog breeds will bark more than others and breeds of terrier like the Yorkshire or Cairn terrier can be very vocal.
One thing not to do is shout at your dog when it barks. To the dog this just sounds like you are barking back at it and is very counter productive. The best thing to do is reinforce and reward good behaviour, so when the dog is quiet say "Quiet, good boy/girl" and then reward. In a calm voice you can point out that barking is not acceptable with your choice of command but never shout.
If there is a real problem with barking do try to sort it out as quickly as you can. The problem can become ingrained in the dog's regular pattern of behaviour and the longer you leave it the more difficult it is to fix.
If all else fails do make sure that your dog's barking is not down to a medical problem or form of senility. Some very insecure dogs will also bark a lot so it is a good idea to reassure them and comfort them as much as you can.