This media is in the public domain (free of copyright restrictions). You can copy, modify, and distribute this work without contacting the Smithsonian. For more information, visit the Smithsonian's ...

This media is in the public domain (free of copyright restrictions). You can copy, modify, and distribute this work without contacting the Smithsonian. For more information, visit the Smithsonian's ...

We independently review everything we recommend. When you buy through our links, we may earn a commission. Learn more› By Zoe Vanderweide Zoe Vanderweide is a writer focused on style and accessories.

If you've ever had to spell out words like W-A-L-K or T-R-E-A-T around a dog, you know that some dogs listen in to humans' chitchat and can pick out certain key words. Well, it turns out that some ...