But now, a relatively small study from University of Cambridge scientists shows that sheep might be joining that club.
They did this by rewarding the sheep food when they went to the picture of one of celebrities, and not an unfamiliar face.
If you ever find yourself in the company of sheep, don't be surprised if they seem to recognize you.
"We've shown with our study that sheep have advanced face-recognition abilities, comparable with those of humans and monkeys", she noted in a university news release.
The study's authors first trained the sheep to recognize images of four celebrities: Barack Obama, Jake Gyllenhaal, Emma Watson and Fiona Bruce, chosen because there were lots of available images from lots of angles.
The woolly creatures could reliably pick out their human handlers without any previous photographic training at all, showing they can spot a familiar face.
Scientists say the study could help advance research of Huntington's disease, which causes humans to lose their ability to recognize faces, Sky News reported. Recently, scientists created genetically modified sheep that have Huntington's.
For the initial training, the sheep received a food reward for choosing the face versus a blank screen. Given a choice, the sheep picked the familiar celebrity's face over an unfamiliar face the majority of the time, the researchers report November 8 in Royal Society Open Science.
A sheep looking at a photo of Emma Watson. The sheep didn't do as well but still passed, recognizing the celebrities about 68 percent of the time - a drop in performance comparable to that seen in humans performing the same task.
Obviously the study focused on only eight domestic sheep, and it does mention some potential alternative interpretations of the data.