One of these things is not like the other: A 3-D printed model of a beige cowbird egg stands out from its robin's egg nest mates, though their shape and heft are similar.
Ana Lopez/Courtesy of Mark Hauber
Plankton collected in the Pacific Ocean with a 0.1mm mesh net. Seen here is a mix of multicellular organisms — small zooplanktonic animals, larvae and single protists (diatoms, dinoflagellates, radiolarians) — the nearly invisible universe at the bottom of the marine food chain.
Christian Sardet/CNRS/Tara Expeditions
An ancient stone tool unearthed at the excavation site near Kenya's Lake Turkana. It's not just the shape and sharp edges that suggest it was deliberately crafted, the researchers say, but also the dozens of stone flakes next to it that were part of the same kit.
The most recent common ancestor of all today's snakes likely lived 120 million years ago. Scientists believe it used needle-like hooked teeth to grab rodent-like creatures that it then swallowed whole.
Julius Csotonyi/BMC Evolutionary Biology
Families harvest poppy bulbs in the Badakhshan province of Afghanistan. To collect the opium, they score the bulbs and let the milky substance ooze out. The dried residue contains about 10 percent morphine.
David Guttenfelder/AP/National Geographic