Have you ever been walking down the street when a dog comes running at you across a lawn? Right when you think he's going to join you on your walk, he skids to a stop at the edge of the lawn, just short of the sidewalk.

What's going on here? It's almost like the dog sees a fence that's not there. But that's crazy, right? There's no such thing as an invisible fence…or is there?

You bet there is! Thanks to modern technology, pet owners can now keep their pets safely inside the boundaries of their lawns without building tall fences. Is this magic? Nope! It's just a combination of science, technology, electronics, and training.

Some invisible fence systems feature wires buried in the ground around a set perimeter, such as a yard. A transmitter connected to the wiring emits a radio signal that travels throughout the underground wire.

The other key component of the system is a receiver worn on a collar by your pet. The receiver detects the radio signal that travels along the buried wire.

As an animal with a receiver collar approaches the buried wire, it will first hear a warning sound that only it can hear. If the animal continues to approach or crosses the buried wire boundary, it will receive a static correction.

A static correction is a mild, harmless electric stimulation that gets the animal's attention. Some people call this a "shock," but it doesn't harm the animal. Instead, animals experience a light tingling feeling on their skin that serves to startle them and interrupt their behavior.

During training with an invisible fence, pets are taught to stop when they receive the warning sound upon approaching the set boundary. How do they know where the boundary is? Most trainers will clearly mark the boundary with flags during training.

Over time, pets learn that approaching the flags will result in a warning tone and, if they don't stop, a static correction. As they receive rewards for stopping short of the boundary, pets learn to respect the boundaries of the invisible fence. Eventually, the flags can be removed, as animals will learn exactly how far they can travel without hearing a warning sound or receiving a static correction.

Of course, with advances in technology, even invisible fences eventually went wireless. Today, you can set up an invisible fence without burying any wire around the perimeter of your yard. Instead, a wireless transmitter sends out a radio signal in all directions to create a circular "safe zone" that you can customize to fit your needs.

With a wireless system, your pet's collar receives the signal constantly while in the safe zone. If your pet approaches the boundary of the safe zone, however, losing the signal will first create a warning sound and, if your pet doesn't return toward the safe zone, a static correction.

Invisible fence systems allow you to keep your pets safe and close to home without the expense and trouble of building conventional fences. With a bit of training, your pet will soon be running around the yard without worry!

Wonder What's Next?

Tomorrow’s Wonder of the Day is a bit dirty and disheveled!