While there are many theories on why dogs howl, no one knows exactly why they do it. While it is known that dogs howl to communicate, to get attention or announce their presence, there is no single answer for the behavior. Because it's difficult to study wolves in the wild due to their unpredictable behavior, there is limited research on howling. Most of the focus is on more common behavior, such as barking or human and dog interaction.
Howling and Communication
As dogs' distant relatives, wolves howl to communicate with the pack about their location or to keep other animals away. It might be that this behavior is ingrained in them as well. This could translate to a domestic dog howling at sirens, people or other dogs as a way to let them know where they are. Some breeds, like malamutes and huskies, tend to howl more often than others, as stated by petMD. Howling isn't a problem and is just a natural mode of expression for most dogs unless it's coupled with aggression toward other people or pets.
Separation Anxiety and Medical Issues
Some dogs howl because of separation anxiety. If this behavior occurs when the dog is alone for periods of time, it's likely because the dog experiences stress and anxiety when separated from its family. This might also be combined with other symptoms like inappropriate elimination, destruction of property or pacing. If this is the case, it's best to contact a veterinarian for conditioning and treatment. Another possible reason for howling can be illness or injury, so if your dog starts howling for no reason or it's accompanied by other unusual behavior, it's best to contact a vet to rule out any possible medical issues.
How to Minimize Problematic Howling
Some dogs howl to get attention from humans or to ask for things they want like toys and food. It is possible to discourage this behavior using a few different methods, as reported by WebMD. Don't scold the dog for this behavior, and instead teach it that howling won't get it what it wants. Try to completely ignore the dog when it howls. Don't talk to it, look at it or touch it. This reinforces that howling won't get it any type of attention, negative or otherwise. One way to reinforce good behavior, such as when the dog is being quiet, is to give it treats or attention. If the dog is howling, wait for the behavior to stop for at least five seconds before giving attention or rewarding it.
If your dog howls when it's alone, try to spend more quality time when you're together. Dogs are social animals, and the more love and attention you can provide while you're together, the better. Take the dog for walks, spend more time playing, try fun training classes and provide the dog with more toys when it has to be alone for long periods of time.