Wild Things: Life as We Know It | Science | Smithsonian
The South American monkey frog and some other tree frogs can endure sunlight and dry air for long periods. (Jason Ortega)

Wild Things: Life as We Know It

Tree frogs, conservation maps and the northern swordtail fish

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Full Body Lotion
Amphibians lose water through their thin skin, so most prefer to stay wet. But the South American monkey frog and some other tree frogs can endure sunlight and dry air for long periods. They secrete a waxy substance from specialized skin glands and use their legs to smooth it over their bodies. Because the animals then close their eyes and sit perfectly still, scientists had long thought the frogs were in a hibernation-like state. But new University of Florida research shows that such frogs aren't dormant after all: their metabolic rate is normal, and they snatch up passing insects. Apparently the frogs freeze to preserve their natural moisture-saving film.

That's Deep
Where to look for new forms of life? Scientists who descended almost two miles into a South African gold mine—besting previous searches for subsurface organisms by a mile and a half—discovered bacteria that survive on energy from uranium. Other bacteria are known to harness radiation, but this finding deepens our understanding of where life can occur on Earth. It also ratchets up the possibility that similar life-forms exist on Mars, which may also have uranium and deep pockets of water.

Observed
Name: Xiphophorus birchmanni, aka the northern swordtail fish, native to Central America and an aquarium mainstay
Male Prefers: to court by raising his sail-like dorsal fin as high as it can possibly go
Female Prefers: a male with a small dorsal fin
Say What?: It's true—she doesn't want what he's advertising, a new study found. So why does the male keep flashing his dorsal fin? To scare off rivals, say Boston University researchers Heidi Fisher and Gil Rosenthal. Thus male competition trumps female choice. Biologists refer to it as intrasexual selection, but others might say it's just another Saturday night.

Conservation's Big Picture
The first detailed world maps of threatened birds, mammals and amphibians show that the creatures are in trouble in different places. The work, published in Nature, underscores that conservation strategies need to be tailored for different types of animals.

Origin of Species (cont.)
Plants may seem to lead simple lives, but their genes can be a blooming confusion. Consider a sunflower that lives in the desert. A Kansas State University study found that its genes bear an unusual abundance of transposons—“jumping” pieces of DNA that multiply and insert themselves into new places in the chromosomes. Why all the genetic hubbub? The sunflower started out as a hybrid, and transposons may have kept it from crossbreeding with other plants, allowing it to become an established species in its own right.

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