A lot happened in 2013. National Geographic covered a wide range of stories and topics, from the deepest space to our DNA, from the highest peaks to the history of language.
These stories struck a particular chord with our readers, who shared them more than any others on Facebook, Twitter, and Google+.
Which stories from 2013 inspired you the most? Let us know in the comments. And while you're at it, check out National Geographic's Year in Review.
Mosquitoes have long plagued humanity, spreading lethal diseases like malaria and West Nile virus and ruining picnics by being annoying pests. Chemical repellents like DEET can help keep them at bay, but some people would prefer less toxic alternatives.
Now, Ulrich Bernier, a research chemist at the U.S. Department of Agriculture's Agricultural Research Service, is developing a new repellent that he says is "so much better than anything else we've ever seen."
Bernier has been testing combinations of natural compounds that are already found in the body, which he says appear to mask a person from mosquitoes. A lot more testing needs to be done before any products appear on the shelves, but Bernier is optimistic.
Commenter Haven Strange asked, "Ok, so what can we do to enhance our body's chemistry to naturally produce these insect repellant chemicals when needed?"
Buried under miles of ice, Antarctica's mysterious mountain ranges are coming into sharper focus, thanks to a new map. Created by the British Antarctic Survey, Bedmap2 drew upon millions of new measurements of the frozen continent's surface elevation, ice thickness, and bedrock topography collected over several decades from a wide variety of sources.
Much of the data for the new map was obtained by NASA airplanes that fly over the frozen continent and use lasers and ice-penetrating radar to measure the topography. Scientists hope the map will help people better understand the region.
Commenter Daniel Krause wrote, "The sheer beauty of this is amazing. Thank you National Geographic for once again giving me another map to add to my collection!! And for ruining my productivity for the day.....under the ice......surface ice......under the ice......surface ice......like a little kid in a candy store."
A 120-million-year-old bird sported a long tail and a second, unexpected tail frond, paleontologists suggest. One of the tails may have been for flying and the other may have been for showing off. The discovery also points to a complicated evolutionary path for the tails we see in birds today.
One of the oldest known birds, Jeholornis, lived in what is today China. Scientists had previously thought it had one long tail, but new evidence suggests it had two.
Commenter Daniel Hughes noted that the second tail "looks like a rudder."
Although ugly is in the eye of the beholder, there are some pretty strange-looking creatures on the planet. The Ugly Animal Preservation Society recently held a poll to determine which species is the least attractive, and the blobfish took first place.
Rounding out the top candidates was the proboscis monkey, the axolotl, the kakapo, and the Titicaca water frog.
Commenter Christian Gonzalez wrote, "I would own a blobfish as a pet. As well as cuddle with it."
In dramatic video that was released only on NationalGeographic.com, a jaguar is seen stalking and then killing a caiman in Brazil's Pantanal, a vast region that is often called the world's largest wetland.
With one bite, the big cat likely delivered an immediate blow to the caiman's central nervous system, leaving the animal unable to fight or flee, according to Luke Dollar, a conservation scientist who helps manage National Geographic's Big Cats Initiative and who narrated the video. Jaguars have the strongest bite of any cat, he added.
Commenter Nilesh Kakade wrote, "Wow! It definitely takes guts to attack a crocodile in a river/water body where it is extremely lethal. This jaguar is one terrific personality. He sure gets my vote. And, of course, brilliant videography!"
Over the past few years, Michael "Nick" Nichols has been photographing lions in Africa's Serengeti. To capture never-before-seen images for the August issue of National Geographic magazine, Nichols employed a range of high-tech tools, from infrared photography to micro-drones, with a special vehicle he dubbed the "lion car."
"Nothing was easy; it was trial and error," Nichols said about his process.
Commenter Patricia Mills wrote, "Wow. . . this is my life's dream. . . to go to Africa. This guy is amazing and he's good at what he does. Thank you SO much for allowing me to see Africa through his 'eyes' and keep up the good work, guys!!!"
Lemurs have identifiable personality traits that are consistent from situation to situation, and those tendencies may have evolutionary implications, according to a new study conducted at the Duke Lemur Center.
"There's actually evidence of heritability in these traits," a Duke scientist explained, which would have implications for the evolution of the species.
Commenter Ann wrote, "I don't think domestication introduced individual personalities, so if dogs and cats have unique personalities, it stands that other animals possess innate individual personality traits as well."
Who doesn't love tiny things? A new species of wasp discovered in Costa Rica pushes that envelope. Named Tinkerbella nana after Peter Pan's miniscule assistant, the insect averages 250 micrometers long. That's 0.01 of an inch—little wider than the diameter of a human hair.
Other tiny creatures include Southeast Asia's pygmy tarsiers and Madagascar's mouse lemurs, a tiny frog from Papua New Guinea, a tiny bat from Southeast Asia, and the bee hummingbird from Cuba.
Commenter Sudarsan said, "That's the beauty of Nature. Amazing to see these tiny tots actually co-exist on this Earth!!"
In June, when the moon made its closest approach to Earth for the 2013 calendar year, it appeared 8 percent larger and 17 percent brighter than usual. "We saw it from the field with fireflies and hay bales. It bleached out the stars," tweeted one fan of the phenomenon.
Commenter Maria Bianchi wrote, "Fabulous photos! ...I really enjoy being able to see these sights and will share them with my students at school."
Some lizards and other animals are masterful at regenerating lost body parts—a feat we humans are sadly less capable of doing (except in the case of our liver). These crafty animals include the axolotl, which can regrow limbs or even parts of its heart, brain, and jaw.
Deer can regrow antlers, and sea squirts can regenerate whole bodies, seemingly defying aging. Starfish and flatworms also have impressive abilities to regrow lost parts.
Commenter Steven Rafter added, "Funnily enough – humans are not too bad at it either – we replace skin and hair constantly… it's the organs, limbs and neurons that we gotta work on…"