Here is a selection of readers’ comments. They have been lightly edited and condensed for clarity. If you’re also having a hard time accepting the study’s findings, tell us in the comments.

A Dog That Heeds Oral Warnings

By far, the smartest dog I ever met was Mr. Sunshine, Sunshi, a golden retriever. We had many long conversations, and I have no doubt that Sunshi understood.

I never had to tell him something twice. Just one example: We were out for a walk, and there was some glass on the sidewalk. I said, “Sunshi, that’s glass and it can hurt your paws,” and he walked around it.

— Eugene, New York City

A Dog Whose Paw Is More Than Just a Paw

My late, beloved dog Sylvie loved eating the tall grass that grew along our walking route. The stems were tough to pull out with her teeth alone, so she would use her paw to bend the stem, and then while the blade was tightly gripped in her jaw, she would exert a quick thrust to sever it.

Sylvie used her paw like a tool — a scythe, to be exact.

— Bill Bartelt, Chicago

A Dog That Turns Humans Into Tools

Dogs use humans as tools. Does any other species do that? If a ball is stuck under the entertainment center, after trying, the dog will come and get me by barking or nudging me.

— adonovzn, Pennsylvania