The 1.5-inch-long (4-centimeter-long) frog "is rather strange-looking—it’s quite fat with short legs and bright orange spots on its sides," said Luis German Naranjo, WWF Colombia‘s conservation director.

Naranjo and a team of scientists were surveying wildlife in eastern Colombia’s Orinoco savanna, including animals found on a small farm.

Expecting to find little more than livestock, the team was surprised when the farmer’s seven-year-old son, whose name was given only as Camilito, called the group over to a pool. There, in the water, was the small spotted frog.

The team’s herpetologist, Daniel Cuentas, had never seen anything like it, and immediately set out looking for other examples.

Daniel Goldman spends his days working with venomous rattlesnakes, baby sea turtles, and a dozen other types of animals. But he isn’t a zookeeper, or even a biologist. He’s a physicist, studying locomotion at Georgia Tech. In order to test his hypotheses, he builds robots that mimic the ways animals move. Jealous yet?

Popular Science: Why do you have so many sandboxes?

Daniel Goldman: No one has ever studied the complexities of a sidewinder rattlesnake’s movement on sand, its natural substrate. In principle, you can understand how a hummingbird stays aloft or how a shark swims by solving fluid-dynamics equations. We don’t yet have fundamental equations for complex terrain—sand, leaf litter, tree bark. To figure that out, we built giant sandboxes that are equipped with high-speed cameras and can tilt to mimic dunes.

PS: Which animals are the hardest ones to work with?

DG: The rattlesnakes were a lucky break. You put them in a sandbox, and they just start sidewinding—the sideways slithering they do to cross sand. But most animals don’t do what you want. Ghost crabs, for example, are ridiculously fast. In the laboratory, you can get about 10 good trials out of them: They’ll run away from you down a track, where high-speed cameras record them. After that, they seem to decide they are no longer afraid and start trying to pinch you.

"In the Oligocene epoch, from about 34 to 23 million years ago, we would have expected to see a fauna dominated by booid snakes, such as boas and pythons. These are generally 'sit and wait' constricting predators that hide and ambush passing prey," lead author Jacob McCartney, a postdoctoral researcher in the Ohio University Heritage College of Osteopathic Medicine, said in a news release.

The newly discovered species is named 'Rukwabyoka holmani' and was unearthed in the Rukwa Rift Basin of Tanzania. The species genus name comes from the Rukawa region with the Swahili word for snake. And the species name honors J.Alan Holman, a palaeontologist. The team found eight different types of fossil snakes varying in length from 2.6 mm to 5 mm.

Lillywhite started studying this species in 2009, at a site off the coast of Costa Rica. “We’ve looked at hundreds,” he says. “No sea snake we’ve observed has drunk any seawater.”

They only stick to the fresh stuff, but the amount they drink varies throughout the year. These snakes live in a place that goes through drought from November to May. If they were captured during these dry spells, they betrayed their thirst by sipping heavily from fresh water; if they were caught in wetter months, they barely drank. “If the snake drinks fresh water, it’s thirsty,” says Lillywhite. “If it’s thirsty, it’s dehydrated, and if it’s dehydrated, it’s not doing what the textbooks said.”

The team also found that the snakes had significantly less water in their bodies than in the dry months than in the wet ones. Despite having a salt gland and being surrounded in water, the snakes are thirsty and dehydrated for months on end. Lillywhite thinks that they cope by having an unusually high amount of water in their bodies to begin with. They might also have adaptations that help them to lose water slowly, and to withstand the effects of dehydration.

In the wild, it is possible that the snakes use deep springs or estuaries, but they are incredibly widespread and Lillywhite has never found any evidence of them congregating in specific sites.

Instead, rain brings them salvation.

...Megalania ain’t what it used to be. For one thing, the lizard’s bones are so similar to those of other monitor species – belonging to the genus Varanus – that paleontologists have taken to calling it Varanus priscus. And while it seems likely that the big lizard was venomous, recent size estimates have shrunk this “dragon in the dust.”

Let’s have a look at the traditional baseline first. In 2004, working with the relationship between vertebrae size and body length, paleontologist Ralph Molnar proposed that mature Varanus priscus could have been between 23 and 26 feet long, depending on the anatomy of the tail. But other researchers think such sizes are major overestimates. In a 2002 study that critiqued “the myth of reptilian domination” in prehistoric Australia, anatomist Stephen Wroe reanalyzed old body size data and calculated that the lizard probably averaged about 11 feet in total length and, citing earlier estimates from Molnar, wouldn’t have grown much longer than 15 feet.

Size estimates in a 2012 paper by paleontologist Jack Conrad and colleagues came out in between the extremes. While describing a new, large Varanus species that once lived in Greece, the researchers also took a look back at Australia’s ever-contentious lizard. Without the tail, the Varanus priscus specimen in their study had an estimated body length of almost seven feet, meaning that this individuals total length was almost certainly longer than the 11 foot average Wroe suggested. Especially large specimens, Conrad and coauthors noted, could have had bodies almost 10 feet long with the tails trailing behind, although these animals still would have been smaller than the monstrous lizards paleontologists used to reconstruct.

The turtles didn’t know it, but their lives were in the hands of the sandal-wearing vet who has worked for 42 years on animals’ eyes — including those of Lolita the killer whale and thoroughbred Seattle Slew before he won the Triple Crown.

Bette Zirkelbach, manager of the nonprofit Turtle Hospital in the Middle Keys' island town of Marathon, had contacted Karpinski a few months earlier “in desperation” to find a new treatment to help Hook and Jack avoid euthanization. As in the case of many turtles with the same condition, their eye tumors grew back about six weeks after being removed, a process that kept repeating itself.

"We can’t release turtles back into the wild if they don’t have vision in at least one eye," Zirkelbach said.

Karpinski came up with the idea of trying Fluorouracil, an anti-cancer medication used in humans. Karpinski already had found success using it on horses with skin cancer and on a Malayan tapir at Zoo Miami with eye tumors. Maybe, she thought, it would work on the endangered sea creatures.

"Dr. Karpinski got creative," Zirkelbach said. "And honestly, the turtles had nothing to lose."

The Whitley Wildlife Conservation Trust, which runs Paignton Zoo, Living Coasts in Torquay and Newquay Zoo in Cornwall, helped fund the fieldwork with rare amphibians in the mountains of Eastern Tanzania.

It has led to the discovery of two Kihanga reed frogs, a male and female, by Elena Tonelli, a PhD student at Manchester Metropolitan University whose work is part-funded by the trust.

The frogs are officially endangered and the two photographed by Ms Tonelli were recorded in the northern part of the Uzungwa Scarp Forest Reserve, some distance from their only previously known site - a small swamp in the centre of the reserve.

The student has since also found the species, which hadn’t been seen at all for a decade, at the original site.

Researchers discovered the dinosaur's remains in 2006 in the Prince Creek Formation on Alaska's North Slope. At the same quarry, Fiorillo and Tykoski have previously uncovered other important finds, such as remnants of the horned dinosaur species Pachyrhinosaurs perotorum, whose discovery was announced in 2011.

"I find it absolutely thrilling that there is another new dinosaur found in the polar region," Fiorillo said in a statement from the Perot Museum. "It tells us that the ecosystem of ancient Arctic was a very different place, and it challenges everything we know about dinosaurs."

[...]

A Tyrannosaurus rex would have weighed between 7 and 8 tons, with a length of about 40 feet. By comparison, an adult Nanuqsaurus might have been only 25 feet long, with a weight of 1,000 pounds. The head was probably about 2 feet long, CNN affiliate WFAA reported.

"There were features in these specimens that were unique; you didn't see them in other tyrannosaurs," Tykoski told WFAA.