If you're looking for a dog to guard your front door or keep intruders out of your yard, the loudness of the dog's bark is certainly a consideration. Not many burglars have turned away from their nefarious deeds due to a tiny bark from the other side of the door. Big barks usually indicate big dogs, and most people would rather move on than assume the big dog on the other site of the gate is a teddy bear in Rottweiler's clothing. Understanding the loudest dog barks requires familiarity with how humans hear sound, and with dog barks in general.
Bred to Bark
The general rule for barks goes like this: bigger dogs have bigger barks. While this is certainly true in most cases (Great Danes have massive barks, for example), some breeds are bred with barks in mind. Guarding breeds like German shepherds, Rottweilers, doberman pinschers and bullmastiffs have massive barks thanks to years of selective breeding for the task of keeping the people and property around them safe from intruders. Any dog bark can be loud, but big dogs bred for protection are usually going to land near the top of the decibel scale.
Why Dogs Bark
If you have a dog, you've probably noticed that he has more than one type of bark. There's the "Someone's at the door" bark, the "Kick me the ball" bark and the "Why did you lock me in the closet" bark. Dogs bark for a variety of reasons, including boredom, fear, confusion, a desire for attention and just the fun of it. You'll get your loudest barks when the dog is attempting intimidation, which usually occurs if he is being protective or is frightened.
Measuring the Decibels
While some dogs sound as if they have loud barks, the way humans interpret a sound isn't always related to its actual volume. High-pitched barks often seem louder due to their piercing nature, while low barks are less intrusive on human ears but could be louder in terms of raw decibels. Choosing the loudest dog breeds requires the barks to be measured in terms of decibel count. It's worth noting that any sound over 85 decibels is considered potentially harmful to human ears, and many dogs are capable of topping this threshold with their powerful barks.
The World Record
The current world record for loudest dog bark belongs to Daz, a German shepherd with a mighty 108-decibel roar. Daz's record was set in 2009 at a special press event for the Disney film Bolt, and was authenticated by the Guinness Book of World Records. Daz's owner was sure to thank the postwoman for giving Daz something to bark at every day—much-needed practice on his path to the record. That decibel count, for reference, is just a little louder than a motorcycle or power mower.