Crows have been shown to understand the concept of zero
The more I learn about animal intelligence, the more I suspect we grossly underestimate it.<p>I recently saw a video of a seagull that entered a grocery store through the automatic door, picked up a (non-transparent) bag of potato chips (or something similar), walked out again, opened the bag and ate the chips. Think about it for a moment, the bird has to understand (to a degree) how an automatic door works, and that there is food inside these shiny bags. When let that sink in, I was thoroughly impressed. I knew seagulls are very opportunistic eaters, but I did not know they were capable of this degree of intelligence and planning.<p>I wonder how much more there is discover, and how that might affect how we view and more importantly treat animals. We might have to rethink our relationship with them.