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.