We, of course, cannot read animals’ minds (even our pets) but that doesn’t mean we can’t intuit some of the ways they feel pain. According to evolutionary biologist Robyn J. Crook in a recent TED-Ed video, humans have two kinds of reaction to pain. First, nerves sense pain, communicate it and cause a jerking reaction. Second, there is conscious recognition—this is what we associate with emotions, including fear. Through observation, it can be deduced that some animals experience pain the exact same way. This is certain for most vertebrates, but appears to apply to some invertebrates as well. Read more at VOX or watch the video at TED-Ed.