Inside of a Dog -- Young Readers Edition: What Dogs See, Smell, and Know

One scientist coined a word for it: umwelt, or “self-world.” (You say it OOM-velt.)

Adult dogs and wolves lick muzzles simply to welcome another dog back home, and to get a report, by smelling, of where the newcomer has been or what he has done.

In one study, the dogs made 1,272 attempts to detect which patients had cancer—and missed only fourteen times. In another experiment, they sniffed out the cancer every time.

A creature’s umwelt is made up of all the things that matter to that creature—all the things it notices or needs, can eat or sleep on or climb or fight with or run away from.

But it is not so simple. Dogs, like human beings, are more than their ancestry. They are not simple carbon copies of their parents. Each dog is different at birth, and each dog will lead his own life. How the dog is raised and treated, what the dog experiences, and who he meets, will shape who the dog becomes.

Even the future can be smelled—on the breeze that brings air from the place you and your dog are headed together.

This meant that by breeding the animals for tameness, Belyaev had actually created a different animal.

For dogs, smell tells time.

If a dog meets another who might be a threat, he wants to appear to be a big, powerful creature, so he makes a big-dog sound, a low growl.