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Tuesday, March 6, 2012

Shark Swallows Another Shark Whole

Miniature Chameleons Discovered—Fit on Match Tip

T. Rex Bite Strongest Ever on Land—Ten Times Greater Than Gator's

A model of a Tyrannosaurus rex skull.
The recontructed skull musculature of a South Dakota T. rex (file picture).

Photograph by Ira Block; model by Brian Cooley

Charles Q. Choi

for National Geographic News

Published February 28, 2012

Once the largest known carnivore on land, Tyrannosaurus rex also had the most powerful bite of any terrestrial animal of any time period, a new study suggests.

(Related video: "T. Rex's Bone-Shattering Bite Filmed.")

Much conventional wisdom about the world's most famous dinosaur species has been called into question in recent years—for instance, whether the 40-foot-long (12-meter-long) T. rex species could run or only plod along.

Likewise, some have contended that the supposedly mighty predator actually had a modest bite, limiting T. rex to scavenging.

To see how forcefully T. rex could bite, biomechanicists involved in the new study used laser scanners to digitize juvenile and adult T. rex skulls. The team then used computer models to reconstruct the dinosaur's jaw muscles and analyze bite performance.

The models suggest that an adult T. rex was capable of a maximum bite force of 35,000 to 57,000 newtons at its back teeth. That's more than four times higher than past estimates and ten times as forceful as the bite of a modern alligator.

T. rex, which went extinct about 65 million years ago, "probably lives up to its reputation as a ferocious biter," concluded study leader Karl Bates, a computational anatomist at the University of Liverpool in the United Kingdom.

(Also see "New 'Destroyer' Dinosaur Found—Was T. Rex Relative.")

T. Rex No Match for Megatooth?

Although T. rex may have possessed the most powerful bite of any land animal, it apparently paled in comparison to that of prehistoric megalodon—literally "megatooth"—sharks, which may have grown to lengths of more than 50 feet (16 meters) and weighed up to 30 times more than the largest great white.

Past megalodon research suggests these giant marine predators, which first appeared around 16 million years ago, could chomp with more than three times the force of T. rex, based on the new figures.

The bite force of a megalodon—"just because it was so much larger-bodied—would have been bigger," Bates said.

So T. rex could have bitten with ten times the force of an alligator. But would it have?

Answering that question would require an estimate of how much stress T. rex's skull could take, Bates said—to help pinpoint just how forcefully the predator could have bitten down with without hurting itself.

A painting of everyday life in a Maya village. Illustration by H. Tom Hall, National Geographic John Roach for National Geographic News Published De

Monument text's "poetic flourish" confuses modern minds, experts say.An illustration of everyday life in a Maya village.

A painting of everyday life in a Maya village.

Illustration by H. Tom Hall, National Geographic

John Roach

for National Geographic News

Published December 20, 2011

It's remotely possible the world will end in December 2012. But don't credit the ancient Maya calendar for predicting it, say experts on the Mesoamerican culture.

(Related pictures: "2012 Doomsday Myths Debunked.")

It's true that the so-called long-count calendar—which spans roughly 5,125 years starting in 3114 B.C.—reaches the end of a cycle on December 21, 2012.

That day brings to a close the 13th Bak'tun, an almost 400-year period in the Maya long-count calendar.

But rather than moving to the next Bak'tun, the calendar will reset at the end of the 13th cycle, akin to the way a 1960s automobile would click over at mile 99,999.9 and reset to zero.

"We, of course, know that really means a hundred thousand [miles] and not zero," said William Saturno, an expert on Maya archaeology at Boston University.

"So, is [the end of Bak'tun 13] a large period ending? Yes. Did the Maya like period endings? Yes," Saturno said.

"Would this have been a period ending they thought was wicked cool? You bet. The biggest period endings they experience are Bak'tun endings."

But "was it predicted to be the end the world? No. That's just us."

Instead, for the Maya, the end of the long count represents the end of an old cycle and the beginning of a new one, according to Emiliano Gallaga Murrieta, the Chiapas state division director of Mexico's National Institute of Anthropology and History.

"It is like for the Chinese, this is the Year of the [Rabbit], and the next year is going to the Year of the Dragon, and the next is going to be another animal in the calendar," Gallaga said.

(Watch the full episode of 2012: Countdown to Armageddon online from the National Geographic Channel.)

Maya Prophecy for End of the World?

Written references to the end of Bak'tun 13 are few. In fact, most Maya scholars cite only one: a stone tablet on Monument 6 at the Tortuguero archaeological site in Mexico's Tabasco state. (Take a Maya quiz.)

What exactly the tablet says, though, is a mystery, because the glyphs in question are partially damaged.

Nevertheless, scholars have taken several stabs at translations, the most prominent in 1996 by Brown University's Stephen Houston and the University of Texas at Austin's David Stuart.

Houston and Stuart's initial interpretation indicated that a god will descend at the end of Bak'tun 13. What would happen next is uncertain, although the scholars suggested this might have been a prophecy of some sort.

This 1996 analysis was picked up "on many New Age websites, associated forum discussions, and even a few book chapters" as evidence that the Maya calendar had predicted the end of the world, according to Stuart.

(See "2012 Prophecies Sparking Real Fears, Suicide Warnings.")

Houston and Stuart, however, independently revisited the glyphs recently and concluded that the inscription may actually contain no prophetic statements about 2012 at all.

Rather, the mention of the end of Bak'tun 13 is likely a forward-looking statement that refers back to the main subject of the inscription, which is the dedication of Monument 6.

In an October blog post about his conclusions, Stuart makes an analogy to a scribe wanting to immortalize the New York Yankees' 1950 sweep of the Philadelphia Phillies in that year's World Series.

If this writer were to use the Maya rhetorical device thought to be in Monument 6's inscription, the text might read:

"On October 7, 1950, the New York Yankees defeated the Philadelphia Phillies to win the World Series. It happened 29 years after the first Yankees victory in the World Series in 1921. And so 50 years before the year 2000 will occur, the Yankees won the World Series."

Written this way, Stuart notes, the text mentions a future time of historical importance—the 50-year anniversary of the victory—but it does so in reference to the event at hand, i.e., the 1950 game.

"This is precisely how many ancient Maya texts are structured, including Tortuguero's Monument 6," Stuart writes.

2012 Apocalypse Just Poetic Flourish

According to INAH's Gallaga, this structure of Maya texts is what has confused modern minds, given our penchant for literal, straightforward reading.

Even if the Monument 6 inscription refers to a god coming down at the end of Bak'tun 13, it isn't a statement about the end of the world, he said.

"They are writing in a more poetic sense, saying, Well, on the 21st of December 2012, the god is going to come down and start a new cycle and the old world is going to die and the new world is going to be reborn—just to make it more poetic."

(Read about the rise and fall of the Maya in National Geographic magazine.)

Saturno, the Boston University archaeologist, agreed that the reference to a specific date is clear in Monument 6, but added that "there's no text that follows and says, Herein will be the end of the world, and the world will end in fire. ... That's not anywhere in the text."

(Related video: Surviving 2012—Preparation.)

Rather, Saturno said, the hype around 2012 stems from dissatisfied Westerners looking to the ancients for guidance, hoping that peoples such as the Maya knew something then that could help us through difficult times now.

In any case, even if the ancient inscriptions explicitly predicted the end of the world, Saturno wouldn't be worried, given the Maya track record with long-range prophecy.

"They didn't see [their] collapse coming. They didn't see the Spanish conquest coming."

Spiny, Venomous New Sea Snake Discovered—"Something Special"

A new species of sea snake.
The newfound sea snake Hydrophis donaldi.

Photograph courtesy Bryan Fry, University of Queensland

Sea snake scales.

The new sea snake's rough scales are seen in detail. Photograph courtesy Bryan Fry, University of Queensland

Christine Dell'Amore

National Geographic News

Published March 2, 2012

A new species of venomous sea snake mysteriously covered head to tail in spiny scales has been discovered in treacherous seas off northern Australia, a new study says.

Though some other sea snakes have spiky scales on their bellies, "no other [known] sea snake has this curious feature," study leader Kanishka Ukuwela, an ecologist at the University of Adelaide, said by email.

Normally snakes have smooth scales, but each of the newly named Hydrophis donaldi's scales has a spiny projection, he said.

Scientists cruising shallow seagrass beds in the Gulf of Carpentaria (map)recently captured nine of the rough-scaled reptiles.

"The minute the first one landed on the deck, I knew we had something special," study co-author Bryan Fry of the University of Queensland in Brisbane, Australia, said by email. "It was quite unlike any of the sea snakes I have seen."

Each of the specimens was found on the rocky seafloor, a habitat that could explain the new species' uniquely strong scales, Fry noted.

Overall, though, "we don't know why this interesting feature evolved in this species, or what they are used for," study leader Ukuwela said.

(See a picture of a "two-headed" sea snake.)

Venomous Snake Has Deadly Neighbors

The new Hydrophis—literally "water serpent"—likely eluded notice for two reasons. The species is apparently rare, and it lives in coastal habitats largely avoided by fishers, Ukuwela said. Many Australian sea snake species live in the open ocean and are often accidentally caught in prawn trawls. (See snake pictures.)

Little is known about the yellowish brown reptile, other than that it gives birth to live young and, like nearly all live-bearing sea snakes, is "venomous and potentially dangerous to humans," according to the study, published February 21 in the journal Zootaxa.

Furthermore, venom is just one obstacle to unraveling the new species' mysteries, the University of Queensland's Fry noted.

"Field observations are impossible, because the water is very murky and filled with lots of very large bull sharks and saltwater crocodiles, in addition to [highly poisonous] box jellyfish," he said.

"If we tried to dive there, our life expectancy would be measured in minutes. The only question is which animal would kill us.

"My money is on the bull sharks."