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Someone is always predicting the end of the world, it seems. The latest popular theory says that the world will end on December 21, 2012, when the Mayan calendar will reach the end of its 5,126 year cycle. That alone is fairly nuts, as USAToday wrote two years ago:

“For the ancient Maya, it was a huge celebration to make it to the end of a whole cycle,” says Sandra Noble, executive director of the Foundation for the Advancement of Mesoamerican Studies in Crystal River, Fla. To render Dec. 21, 2012, as a doomsday or moment of cosmic shifting, she says, is “a complete fabrication and a chance for a lot of people to cash in.”

But the theory has gotten even crazier since then, as astronomer Neil DeGrasse Tyson notes in the video clip above. There are tales of an alignment between the Earth, Sun and the galaxy that will end in great catastrophe. There is Nibiru, a.k.a. Planet X, which will supposedly come close enough to Earth to knock the planet off its axis, with resulting calamity. (NASA has a great page debunking Nibiru.) And there’s even more.

I had thought that end-of-the-world predictions and cults were a 20th-century invention until I read recently about some dating to the early 1800s. It doesn’t matter that prediction of the future is impossible in an Einsteinian universe (that would be the one we live in). There will be people crazy enough to make this stuff up and others gullible enough to believe it. Don’t be one of them.

So, when 12/21/12 comes along, don’t despair. Instead, let’s celebrate the end of the Mayan calendar cycle. Who’s bringing the beer?

Without landmarks, we easily walk in circles (courtesy of flickr user helter-skelter)

In the movies, when hikers get lost in the woods, you know that they are well and truly lost by the third time or so that they pass by that big rock or funny-looking tree. And you just know that that would never happen to you. If you set out on a straight line, you would never double back without intending to do so.

Well, you’d be wrong.

People do walk in circular paths when they are lost, according to a study published online today by Current Biology. Scientists from the Max Planck Institute for Biological Cybernetics in Germany started their experimentations by first letting a few volunteers loose in a large, flat German forest and tracking them by GPS. Those who wandered on a sunny day kept to a nearly straight path while participants who trekked on a cloudy day walked in circles. Three of the cloudy day walkers even repeatedly crossed their own paths and without ever realizing what they were doing.

The scientists repeated their experiment in the Sahara Desert in Tunisia. Two people who walked during the day veered a bit off course (not too shocking when every direction looks similar) but the participant who walked at night managed to keep to a straight line only until the moon became covered by clouds.

In another experiment, the scientists blindfolded their subjects, who were then told to walk a straight line. But without anything to guide their paths, they walked in circles.

Throughout the experiments, though, the participants did not favor any one direction. Sometimes they would veer left, at other times, right. This rules out the idea that we walk in circles because we favor one leg over the other due to leg length or strength. Instead, the scientists say, without something like the sun or a mountain around to help us calibrate “straight,” the “noise” in our sensorimotor system sends us off track. However, the scientists note:

In emergency situations, where one’s life depends on the ability to navigate through unfamiliar terrain and reach safety, emotional state (panic) and social factors (group dynamics) may cause these cues and more cognitive navigation strategies to be disregarded, making people walk in circles even in the presence of reliable directional cues.

In the researchers’ next experiment, they will have participants walk through a virtual reality environment on a treadmill that lets a person walk in any direction (video below) to better determine the factors that help a person to walk straight or sets them into circles.

The big cats get all the attention, it seems. Lions, tigers and cheetahs are all threatened, but they are not the only cat species whose populations are in danger. Here are seven small cat species under threat:

Black-footed kitten (courtesy of flickr user Asten)

Black-footed cat (Felis nigripes)
Lives in: the steppes and savannas of southern Africa
Eats: mostly rodents, shrews and birds, but also large insects, spiders, small snakes and geckos
Spends its days: in burrows or in hollowed out termite mounds
Superlative: the smallest of the African cats
Named for: the black bottoms of its feet
Threatened by: habitat degradation from grazing and agriculture, resulting in declines of the cat’s prey

An oncilla (via Wikimedia Commons)

Oncilla (Leopardus tigrinus)
AKA: Little Spotted Cat, Tigrillo, Cunaguaro, Tiger Cat
Lives in: montane cloud forests and rainforests in Costa Rica and the Amazon Basin
Eats: small primates, reptiles, birds, rodents and insects
Likes to: climb trees
Threatened by: hunting (for pets and pelts), habitat loss and fragmentation, roads

A rusty-spotted cat in the wild (via Wikimedia Commons)

Rusty-spotted cat (Prionailurus rubiginosus)
Lives in: tropical dry forests and grasslands in southern India and rainforests of Sri Lanka
Named for: small, rust-colored spots on its back
In the wild: sleeps in trees and hollowed out logs during the day
At home: can be very affectionate with an owner (but we need them in the wild, not at home)
Threatened by: habitat loss and spread of agriculture

Andean cat (via Wikimedia Commons)

Andean cat (Oreailurus jacobita)
Lives in: the high regions of the Andes of Argentina, Bolivia, Chile and Peru
Known as: “the sacred cat of the Andes”
Known for: its long, stripey tail
Used to eat: mountain chinchillas (now extinct in many places)
Threatened by: hunting for use in local festivals, loss of their mountain chinchilla prey, habitat destruction due to mining, oil extraction and cattle grazing

A drawing of a Borneo Bay cat (via Wikimedia Commons)

Borneo Bay cat (Pardofelis badia)
AKA: Bay Cat, Bornean Cat, Bornean Red Cat or Bornean Marbled Cat
Why we don’t have a photo: they are that rare
Lives in: the forests of Borneo
Eats: ? The cat’s diet has never been studied.
Color: red or gray
Threatened by: habitat loss due to commercial logging and oil palm plantations

Fishing cat (courtesy of flickr user cliff1066)

Fishing cat (Prionailurus viverrinus)
Lives: near marshes, mangroves, rivers and streams in India and Southeast Asia
Where you can find one in D.C.: At Smithsonian’s National Zoo
Eats: birds, small mammals, snakes, snails and fish
Catches fish: with webbed paws
Uses its tail: as a rudder when swimming
Threatened by: wetland destruction due to human settlement, agriculture and pollution

Iberian lynx (via Wikimedia Commons)

Iberian lynx (Lynx pardinus)
Lives in: open grassland and dense shrubland in Andalusia, Spain
Used to also live in: Portugal, but hasn’t been seen there in years
Eats: the European rabbit, hares, rodents, the occasional young deer
Total population: 84-143 adults, according to the IUCN
Superlatives: the most endangered cat species in the world, and one of the world’s most endangered mammals
Threatened by: loss of its main food source, the European rabbit, due to habitat changes, diseases (myxomatosis and Rabbit Haemorrhagic Disease) and hunting

Of all the species of penguins, more than half can be found only outside Antarctica. Here are my top five favorites:

Humboldt penguins in Chile (courtesy of flickr user Andrea Baldassarri)

5. Humboldt penguin: These medium-sized penguins—about nine pounds—live on the rocky coasts of Peru and Chile. They get their name from the Humboldt Current, which runs along the Pacific Coast of South America and was named for 18th-century explorer Alexander von Humboldt. The pink spots on their faces are areas without feathers, which help the birds to stay cool. Slightly disgusting fact: They nest in layers of other seabirds’ guano.

King penguins (courtesy of flickr user chrispearson72)

4. King penguin: Second only to the Antarctic emperor penguin in size, the king penguin grows up to 35 pounds. They live on low-latitude islands such as Tierra del Fuego and the Falklands. King penguins are serial monogamists: they stick with their mate faithfully for a year, but only about 29 percent of the relationships last through the following breeding season.

A Magellanic penguin on Isla Magdalena (courtesy of flickr user Flickmor)

3. Magellanic penguin: Another medium-sized penguin, the Magellanic, can be found in Argentina, Chile and the Falkland Islands, and some even migrate to Brazil. They are one of the four “jackass” penguins, so called for their bray, which can carry into the night. Read Smithsonian’s Penguin Dispatch about the Magellanic penguins of Punta Tombo from earlier this summer. Nearly 200,000 breeding pairs come to breed at this spot off the coast of Argentina.

Galapagos penguin. Image courtesy of Flickr user eatswords

2. Galapagos penguin: The only penguin found north of the equator (at least, outside of a zoo), the small Galapagos penguin is the rarest of all penguin species. There are only around 1,000-1,500 individuals, all living in the Galapagos Islands in Ecuador. Temperature fluctuations due to El Niño have been a main cause of the species decline, but predation by cats introduced to the islands, fishing and oil pollution have also harmed the birds.

A fairy penguin in the penguin parade (courtesy of flickr user marcusfrieze)

1. Fairy penguin: Also called the little or little blue penguin, the fairy penguin can be found on the coasts of Australia and New Zealand. At about two pounds, it is the smallest of all penguin species and, in my opinion, the cutest. Though there are many places to see fairy penguins in the wild, the best might be Summerland Beach on Phillip Island in Australia. Each night, after a day of fishing, the penguins cross the beach to return to their burrows in the sand dunes, with tourists watching the “penguin parade” from boardwalks and viewing stations.

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A Bornean orangutan. Courtesy of Flickr user Graham Racher

An orangutan will produce an alarm call known as a “kiss squeak” when it encounters a predator like a snake or a human. The kiss squeak is produced by drawing a sharp intake of air through pursed lips (see this video for an example). Sometimes, though, an orangutan will take a branch, strip the leaves from it, hold the leaves in front of its mouth and then make the sound. Why?

Researchers studying the wild Bornean organutan (Pongo pygmaeus wurmbii) recorded kiss squeaks made by the animals near a research station. (Their study appears in the Proceedings of the Royal Society B.) They found that the leaves lowered the maximum frequency of the sound (i.e., made it deeper). Also, smaller orangutans were more likely to use the leaves.

The orangutans appear to be using the leaves to make themselves sound like they are bigger than they really are. The scientists say that this is the first case of an animal using a tool to manipulate sound.