Somewhere out there, a man with a shaggy gray beard is walking a shaggy gray terrier, and neither of them has noticed. Everyone else has. Pets looking suspiciously like their owners has been a reliable joke for decades, and it turns out scientists have been checking whether the joke is true.

At least for dogs, the answer is yes, and it's a little embarrassing. In 2025, researchers at Germany's Max Planck Institute of Geoanthropology reviewed 15 studies and found that people tend to choose dogs that look like them, right down to body weight and the length of their hair or ears. Give it a few years, and personalities start to line up too. Lead researcher Yana Bender compares it to the way we choose a partner, which is either romantic or slightly alarming, depending on your dog. Cats, true to form, have been harder to pin down. Still, a UK study of more than 3,000 cat owners found that more neurotic owners were more likely to have anxious cats, while conscientious owners tended to have calmer, friendlier ones. Whether the cats would admit to any of this is another matter.

The 50 pairs below include dogs, cats, and a few other animals that clearly refused to be left out of the research. Some share a haircut, some share a facial expression, and some share an energy no study has a name for yet. Scroll through and tell us which pair made you look twice.