"People are grappling with identity when they become parents, and they're also grappling with identity in terms of who we are online," says psychologist Daphne de Marneffe (not pictured). Jonathan Ross/iStockphoto hide caption

itoggle caption Jonathan Ross/iStockphoto

The egg definitely came before the chicken in this case — the skeleton is from a modern adult kiwi, the egg from its much bigger, long-extinct cousin, Aepyornis maximus. Kyle Davis and Paul Scofield/Canterbury Museum hide caption

itoggle caption Kyle Davis and Paul Scofield/Canterbury Museum

Red blood cells infected with the Plasmodium falciparum parasite. Plasmodium is the parasite that triggers malaria in people. Gary D. Gaugler/Science Source hide caption

itoggle caption Gary D. Gaugler/Science Source

Unlike humans, an octopus doesn't have constant awareness of each arm's location. Each appendage sort of has a "mind of its own," research shows. Joe Parks/Flickr hide caption

itoggle caption Joe Parks/Flickr

Does she really think you're funny, or is she just being polite? Jon Feingersh/Getty/Getty Images/Blend Images RM hide caption

itoggle caption Jon Feingersh/Getty/Getty Images/Blend Images RM