Smooching feels good, of course, but couples first started swapping saliva as a way to test out genetic compatibility.
Dogs have been genetically encoded to understand human behavior.
The same brain hormone affects feelings and behaviors in both chimps and humans, causing humans and chimps to share a variety of traits.
Haven't we all been on an elevator and noticed that just about everyone stops talking when they get on?
Why are diseases like cancer so common in humans but so rare in chimps?
We talk to our house pets all the time, but wouldn't it be great if your cat could answer you in English?
Grooming reduces tension by lowering the heart rate and releasing endorphins that are calming.
It might seem like an obvious question, but what really makes humans different from some of our four legged friends? Learn more on this Moment of Science.