Why do dogs bark?

Barking dog

It's hard to talk about, work with, or even think about dogs without broaching the topic of barking. Even the absence of barking is frequently noteworthy.

As a matter of fact barking can be a very big issue. The sort of issue can lead to dogs being rehomed or...worse. Coppinger and Feinstein ("Hark! hark! The dogs do bark ... and bark and bark"; Smithsonian 1991 - can't find a link.) once recorded a dog barking for seven hours straight.

Why do dogs bark? From an evolutionary context, that's a good question. While wolves and coyotes are capable of barking, it is very rare. Belyaev's famous foxes famously do, much like dogs. (Silver foxes normally do not bark very often.)

I can think of four main "types" for barks off the top of my head, and since that is exactly where this blog entry is coming from, those are the four I will list.

Dogs have very limited vocal abilities, so just like with a dog's body language, context is very important when interpreting a bark. What I find most relevant in terms of the bark itself is the tone and the duration. Generally speaking lower tones are more threatening while higher tones tend to be less so. Likewise, longer sounds tend to also be more urgent or threatening.

  1. Alert or "Hey! There's something going on over there!" Barking This tends to be a mid-to-high pitched bark, delivered in bursts of short barks. I hear this one whenever Caffeine hears a vehicle on our street that she doesn't recognize. (We live on a quiet street.) I also hear it when occasionally when Buddha hears an "interesting" siren. It indicates something new or interesting, but not necessarily threatening.
  2. Alarm or "I don't want to hurt you!" Barking - this is very low in tone and tends to start with a harsh growl. The barking portion tends to be longer in duration. This indicates something threatening or maybe even scary. Gage did this one a lot shortly after he came to our home. We hear it a lot less often now, but since he is fully grown with a huge, deep, chest, I have to say it's really effective. Last week a loose dog, while I was distracted at the far end of the classroom, walked up and apparently sniffed Gage's crate. The entire room stopped while the poor dog bolted back to her human very quickly.
  3. Distress barking - for a variety of reasons our dogs sleep in their crates more often than not. Twice now Caffeine has woke me up because of an emergency. (Each time one of the other two dogs had become ill...but that's another discussion.) The barking woke me up instantly both times. Problem is, I don't know exactly what it sounded like. (Maybe very high in pitch??) It does however, make me think of that one cry a baby has that instantly gets your attention.
  4. Play barking - I have two Border Collie mixes, and a few of my friends have Aussies, so I see quite a bit of vocal play. These barks tend to be high in pitch and very short. However they are less "clustered" than alert barks.

Any thoughts? Anything I got wrong or left out? Let me know!