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The startling discovery of Titanoboa was made by a team of scientists working in one of the world’s largest open-pit coal mines at Cerrejon in La Guajira, Colombia. It is a snake that dwarfs the largest anaconda found today, and it has the size and character to challenge T-Rex in the public’s imagination.

The story behind this significant scientific revelation began in 2002, when a Colombian student visiting the coal mine made an intriguing discovery: a fossilized leaf that hinted at an ancient rainforest from the Paleocene epoch. Over the following decade, collecting expeditions led by the Smithsonian Tropical Research Institute and the Florida Museum of Natural History, University of Florida opened a unique window into perhaps the first rainforest on Earth. Fossil finds included giant turtles and crocodiles, as well as the first known bean plants and some of the earliest banana, avocado and chocolate plants. But their most spectacular discovery was the fossilized vertebrae of a previously undiscovered species of snake, one so large it defied imagination.

Together with their research teams, Jonathan Bloch of the Florida Museum of Natural History, University of Florida and Carlos Jaramillo of the Smithsonian Tropical Research Institute, joined forces with one of the world’s foremost experts in ancient snakes, Jason Head of the University of Nebraska, to unlock the mysteries of this ancient time and discover exactly how Titanoboa appeared, lived and hunted. The fossilized remains revealed that, after the extinction of the dinosaurs, the tropics were warmer than today and witnessed the birth of the South American rainforest, in which huge creatures battled it out to become the planet’s top predators. Dominating this era was Titanoboa, the undisputed largest snake in the history of the world.

Most of the fossil record of ancient snakes is comprised of vertebrae like the one that launched the Titanoboa investigation. Snake skulls are almost never found as they are extremely fragile and usually disintegrate – making it almost impossible to create a full and accurate picture of these extinct creatures. But during the filming of TITANOBOA: MONSTER SNAKE, the scientists managed to uncover not just one, but fragments of three skulls, allowing them to derive for the first time what this ancient giant looked like.

A scientifically accurate, life-sized replica of Titanoboa appears in the film and will go on display for the first time at the National Museum of Natural History beginning March 30, 2012. The exhibition will travel to museums across the country beginning in fall 2013. Titanoboa: Monster Snake is a collaboration between the Florida Museum of Natural History at the University of Florida in Gainesville, the University of Nebraska-Lincoln, and the Smithsonian Tropical Research Tropical Research Institute, and is circulated by the Smithsonian Institution Traveling Exhibition Service.

The two-hour special explores how this monster snake would have lived by visiting its living cousins, boa constrictors and anacondas, in the Florida Everglades and the Venezuelan Grasslands. The scientists’ research yields some intriguing and terrifying insights, including the climate in which it lived and size of the snake. All of these clues come together to paint a picture of Titanoboa’s world, which is brought back to life in stunning CGI. Here we see how the colossal snake ruled as an ancient apex predator among a land of tropical mega-beasts.

TITANOBOA: MONSTER SNAKE follows the scientific sleuths back to the mine, into the labs, and on an expedition to understand modern giant constrictors. It creates a picture of the then largest predator on the planet – a creature that until now has only populated fiction and nightmares, but can finally be displayed as a marvel of nature.

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Males across the animal world have evolved elaborate traits to attract females, from huge peacock tails to complex bird songs and frog calls. But what keeps them from getting more colorful feathers, longer tails, or more melodious songs? Predators, for one. Increased elaboration can draw predators in, placing an enormous cost to males with these sexy traits.

Image right: Female túngara frogs have a limited cognitive ability to recognize increasing elaboration in male mating calls. Fringe-lipped bats that hunt the singing males also have a limited cognitive ability to notice increases in male call complexity. So, the evolution of increasing complexity in male calls is limited by decreased female response rather than increased predation. (Photo composite by Michael Teague O’Mara. Photos by A. Baugh, K. Lampert and A. Lang)

In a new paper appearing this week in Science, a group of biologists have shown that females themselves can also limit the evolution of increased elaboration.

Studying neotropical túngara frogs, they found that females lose their ability to detect differences in male mating calls as the calls become more elaborate.

“We have shown that the female túngara frog brains have evolved to process some kinds of information and not others,” says biologist Mike Ryan of the Smithsonian Tropical Research Institute and University of Texas at Austin, “and that this limits the evolution of those signals.”

Imagine looking at a group of five oranges next to a group of six. At a glance, you would quickly notice that one group has one more orange than the other. Now, imagine looking at a pile of 100 oranges next to a pile of 101. It would be nearly impossible for you to notice the difference in size (one orange) between those two piles at a glance. This is known as Weber’s Law, which states that stimuli are compared based on proportional differences rather than absolute differences (one orange in the case above).

In túngara frogs, males gather en masse to attract female frogs with a call that is made up of a longer “whine” followed by one or more short “chucks.”

Through a series of experiments conducted in Panama, Ryan and his collaborators found that females prefer male calls with the most chucks, but their preference was based on the ratio of the number of chucks. As males elaborate their call by adding more chucks, their relative increase in attractiveness decreases due to a perceptual constraint on the part of females.

Male túngara frog calls also attract a predator: the frog eating fringe-lipped bat. To confirm that male song elaboration wasn’t limited by these predators, the researchers also studied how the bats respond to additional “chucks” in the male call.

They discovered that hunting bats choose their prey based on chuck number ratio, just as the female frogs do. So, as males elaborate their call by adding chucks, the relative increase in predation risk decreases with each additional chuck.

“What this tells us is that predation risk is unlikely to limit male call evolution,” says Karin Akre, lecturer at The University of Texas at Austin. “Instead, it is the females’ cognition that limits the evolution of increasing chuck number.”–Karin Akre, University of Texas at Austin

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Image right: One of Nababiep’s cubs gets an exam from Zoo keepers Leigh Pitsko (left) and Craig Saffoe. (Photo by Mehgan Murphy)

Although the Zoo has managed lions in the past, it has been many years since it had the right combination of animals by age and gender to develop a pride. Doing so successfully has required extensive planning, knowledge of the species’ natural history and an understanding of the individual animals involved.

Luke, the Zoo’s 4-year-old male lion, is father to all seven cubs and is the most genetically valuable lion in the Association of Zoos and Aquariums’ Species Survival Plan for African lions (Panthera leo). An SSP matches individual animals across the country for breeding in order to maintain a healthy, genetically diverse and self-sustaining population.
“We are very proud to play a role in the management of this important species,” said Dennis Kelly, director of the Smithsonian’s National Zoological Park.–Jessica Porter

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Image right: A female C. darwini spider (Photo by Matjaz Kuntner)

Studies of the silk of these spiders by Kuntner, Agnarsson and University of Akron collaborator Todd Blackledge, have revealed it is among the toughest of all known spider silks. The strength of their silk allows them to exploit the open area above waterways—a unique ecological niche.

Above: This video shows a Darwin’s bark spider on her web subduing a dragonfly. (Video by Matjaz Gregoric)

Bark spiders of the genus Caerostris are abundant in Madagascar, a country the researchers describe as a “hot spot” of Caerostris diversity. Surprisingly, given the size of the spiders and their webs, virtually nothing is know about Caerostris natural history, the scientists write.

One characteristic of these spiders, Kuntner and Agnarsson say, is extreme sexual size dimorphism, with large females and much smallermales. Most of what is known about species of this genus is through females collected by researchers, as the males are small, look nothing like the females, and often hide in vegetation close to the females’ webs.

Image left: A large C. darwini web over a stream in Madagascar. (Photo by Matjaz Kuntner)

“Clear understanding of this diversity is critical to conserving these giant orbweavers and their habitat in the rapidly diminishing forests of Madagascar,” the scientists write. A paper describing C. darwini and introducing some of the striking aspects of Caerostris biology was recently published in The Journal of Arachnology. A paper on this spider’s silk was published in “PLoS One.”–John Barrat

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Photo right: An adult Nephila clavipes on its web with an insect it has captured.

To test this theory, Thomas Hesselberg of the Smithsonian Tropical Research Institute in Panama, recently examined and compared the designs of webs woven by newly hatched, mid-size and adult orb-web spiders of the species Nephila clavipes and Eustala illicita. (Nephila grow explosively and an adult can weigh up to 500 times more than it did when newly hatched.) He collected a number of spiders from each age group, induced them to weave webs on square frames in a laboratory and then took careful measurements of each web. He also conducted observations of the webs of both species in the wild. A paper on Hesselberg’s work was published recently in the scientific journal “Ethology.”

Photo left: An N. clavipes resting at the hub of its laboratory web.

Orb-web spiders have a fixed reserve of sticky capture spiral silk inside their bodies prior to web building. This reserve is thought to be entirely used up as the web is completed. “As orb spiders build the capture spiral from the outer periphery towards the hub [or center of the web], they need to match web size to silk reserves,” Hesselberg writes. Younger spiders that haven’t mastered this behavior, he reasoned, should have a larger area free of silk at their web’s center hub. Or, to cover for a miscalculation, a young spider may increase the distance between the spirals of its capture silk spun out nearer to the web’s hub.

In his observations of the different webs, he found no evidence that adult Nephila or Eustala spiders have any more brain power or build webs any more effectively than newly-hatched spiderlings. “Neither species showed clear signs of being behaviorally limited or more prone to committing errors as spiderlings than were older juveniles or adults,” Hesselberg concluded.

Photo right: The web of an E. illicita spider in the wild. (Photos by Thomas Hesselberg).

One miscalculation may lie, Hesselberg adds, in the human assumption that “the orb web is the result of a demanding computational behavioral process. Theoretical models suggest that the construction of the orb web might be achieved by following a few simple rules of thumb and thus not pose any significant computational challenge for the spider.”

–John Barrat

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Photo: A female red-eyed treefrog deposits a clutch of eggs on a leaf overhanging a pond. 

 Recently, researchers from Boston University and the Smithsonian Tropical Research Institute (STRI) in Panama have been taking a closer look at the vibrations that red-eyed treefrog embryos use as cues to trigger early hatching. The researchers—Michael Caldwell and J. Gregory McDaniel of Boston University and Karen Warkentin of both Boston University and STRI—embedded tiny recording devices into red-eyed treefrog egg clutches and recorded the low-frequency vibrations caused by snakes as they ate the eggs and also by tropical rain storms. They played back these vibrations to egg clutches in a laboratory and found the embryos hatched in response to the snake-generated vibrations and not to the rain vibrations.

This infrared video recording show a parrot snake (Leptophis ahaetulla) attacking a red-eyed treefrog egg clutch. Some of the treefrog embryos escape the snake by hatching early.

This experiment showed that the embryos were responding to the vibrations and didn’t need chemical or visual cues from snakes, Warkentin says, and that the embryos could differentiate between snake vibrations and rainstorm vibrations. 

What puzzled the researchers was that the low-frequency vibrations that triggered the embryo hatchings were in some ways very similar to vibrations caused by many benign forest stimuli—such as rainfall, wind or non-predatory animals. “Hatching early in response to benign stimuli would be a serious error” Warkentin explains, “since premature hatchlings are vulnerable to predators in the pond. We reasoned that if a defense—such as hatching early—is costly for prey, then mechanisms should be in place to avoid false alarms, just as mechanisms exist to recognize and defend against predators.”

 Photo: The device in this egg clutch is an accelerometer, used to record vibrations. The vibration recording from a snake attack on an egg clutch is shown below.

In recent laboratory work the scientists improved their understanding of how these false alarm mechanisms work in regard to rainfall. The low-frequency vibrations generated by tropical rainstorms are accompanied by two elements that snake-feeding vibrations do not have: high frequency vibrations and an initial buildup of intensity. When these two features were removed from rainfall recordings and the edited recordings were played back to embryos in the lab, many of the embryos hatched. The intensity buildup and high frequency vibrations played simultaneously with low frequency vibrations indicative of danger suppressed the hatching response.

 “Although we don’t know the precise mechanism—whether, for instance, the high-frequency vibrations mask perception of the low-frequency vibrations that indicate danger, or whether the embryos perceive high frequency vibrations as indicative of safety—we do know that the embryo behavior is affected by these two features of rain vibrations in a way that benefits them,” Warkentin says.

 A paper on this research: “Is it safe? Red-eyed treefrog embryos assessing predation risk use two features of rain vibrations to avoid false alarms,” was published in the journal Animal Behavior at the Web address:  www.elsevier.com/locate/anbehav

Photo: A male red-eyed tree frog (Photos and video by Karen Warkentin)

 The Web site for the Warkentin Lab at Boston University is: people.bu.edu/kwarken/

—John Barrat

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Like Mark Twain’s fictional Tom Sawyer —who, when faced with the burden of whitewashing 30 yards of board fence, persuaded other boys to paint it for him—McShea has rounded up 100 eager volunteers (“who are totally jazzed,” according to the scientist) to collect data for him in the woods along the famous footpath that runs from Georgia to Maine.

For now, McShea’s project covers just a portion of the trail, a 570-mile stretch from the southern border of Virginia to the northern boundary of Maryland. His volunteers, most of them recruited from hiking clubs that maintain the trail, are responsible for setting up some 50 cameras at predetermined points along the route, leaving them in place for a month, and then moving each camera to a new spot.

Infrared sensors allow the cameras to take a photograph whenever an animal strays within range of the lens. The project’s first phase ran from April through November, during which time McShea’s volunteers set up cameras to take animal snapshots at about 350 locations along the Appalachian Trail.

With luck, the photo-shoot project should do more than tally wild carnivores across a ribbon of eastern woodland; it also should tell McShea something about the condition of the landscape those animals roam.

“The Appalachian Trail really doesn’t change that much from Georgia to Maine,” explains McShea, who works at the National Zoo’s Conservation and Research Center, in Front Royal, Va. “It’s mature oak forest up on the top of a ridge, and it just keeps going and going. But what changes is the surrounding landscape. The trail goes through suburbia, through national forest; it passes major highway systems.”

Because predators, especially larger ones, need to cover lots of territory to get an adequate diet, recording their presence or absence as the trail snakes across the varied habitats of the eastern United States measures the fitness of those habitats for wildlife, providing what McShea calls “an index of wildness along the trail.”

The project came about when McShea attended a 2006 conference at which officials from the National Park Service were seeking ways to use volunteers to gather environmental data about the trail. McShea suggested the predator survey, modeled after ones he has done in China and Malaysia, where he trained staff at wildlife reserves to set up and use cameras to take a census of animal populations.

By early 2007, McShea was training volunteers in this country in the fine points of automated wildlife photography. He taught them to strap cameras to trees at about knee height. “Most animals are shorter than you think they are,” he explains, and the camera’s infrared sensor needs to be low enough to be triggered, not just by bears but by foxes and raccoons.

To avoid creating a gallery of hiker portraits, cameras were set up away from the Appalachian Trail itself but along nearby animal trails. Volunteers also were given directional coordinates within a predetermined segment of the Appalachian Trail and instructed to set up their camera within 100 meters of that location.

In addition to cameras, “the stink” was provided to aid McShea’s helpers. “That’s what we call it,” says Ricki Ashcraft, an education specialist at the Conservation and Research Center, who as a volunteer is helping to manage three cameras along a stretch of the Appalachian Trail in Shenandoah National Park. This scent lure, extracted from animal musk glands, is obtained from trapping-supply companies. “It smells to high heaven,” she says. But a drop left on a stick or stone in front of a camera will make a passing predator pause just long enough for the project’s digital cameras to wake up from “sleep mode” and get the picture.

McShea says his volunteers are enthusiastic about the work because “they maintain sections of the trail and they’re always wondering, ‘What’s here? Do they have bobcats on their section of trail, or bears or weasels?’ Some are even doing it because they hope they may photograph a mountain lion.”

For the record, McShea does not believe wild cougars still roam the Appalachians. But perhaps with a nod to Tom Sawyer, he says he’s promised “a bonus” to the first volunteer who records one.

What the project’s cameras have captured is an abundance of bears, bobcats and coyotes; a handful of startled hikers; both red and gray foxes; and a surprisingly small number of raccoons, opossums and skunks.
After shutting down for the winter, McShea intends to resume his experiment in what he calls “citizen science” for another seven months beginning in the spring. Then, having honed procedures for using trail-club volunteers to set up cameras, record habitat information and sprinkle stink, he hopes “to talk someone into letting me do the entire trail.”

That “megatransect” along the entire 2,175-mile Appalachian Trail would, like the current project, seek to determine how the East’s wild carnivores are coping within the variety of natural and highly developed landscapes that bracket the trail through 14 states. Like much of McShea’s research, whether studying giant pandas in China or deer in Virginia, the work has a practical bent.

“I’m trying to be helpful to land managers,” McShea says, “trying to give the guys who work in the Park Service and the Forest Service and the state game agencies information that helps them do their jobs better. And I think this distribution-of-predators study is something they can use to say whether they’re doing a good job or not.”

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