Frogs and toads jump, swim, climb, and even glide. But four strange species of amphibians have evolved a decidedly unfroglike characteristic: a preference for walking. Now, scientists have discovered how they do it.
The Senegal running frog, the bumblebee toad, the red-banded rubber frog, and the tiger-legged monkey frog don’t walk like dogs or other four-legged beasts. Instead, they crawl low to the ground like a cat creeping up on prey.
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Thanks to human activity, some daytime animals are switching over to the night shift.
Justin Brashares noticed it first in 2013, when he was studying olive baboons in Ghana: during times that humans were around, the primates stayed up long past their normal bedtimes. It seemed the creatures had learned that by staying up late, they could avoid being chased down, harassed or even killed. Not only that, but they could get revenge by orchestrating heists on their day-walking evolutionary cousins.
Siblings can be annoying, but for young splash-back poison frogs, they’re also deadly. If placed in the same pool, tadpoles of this species will gladly eat their brothers and sisters.
Now a new study suggests tadpoles have a way to escape their cannibalistic kin: Hitchhiking on the backs of adults.
Female poison frogs usually lay their eggs above water-filled plants, such as bromeliads. When the eggs hatch into tadpoles, prudent fathers often turn up and carry their hatchlings to different plant pools, one by one, so that their offspring won’t eat each other as they develop into colorful adults.
When it comes to eating hard-shelled bugs, the wildly varied species in the Bradypodion genus of dwarf chameleons have evolved an incredible array of a special part for doing the work: their heads. Scientists long wondered why these closely related South African lizards had such diverse noggins—some wide, some tall, and some covered with scaly head or chin frills. So they looked at the diets of 14 of the 17 known chameleon species, and compared them with the lizards’ head type.
The scenes start out innocently enough, often with a springtime stroll through Alaska’s Nelchina River Basin. But without warning, things turn grim: tableaus of blood and gore, usually with an unlucky caribou calf at the center.
Such is the video footage collected by scientists over 3 years from cameras strapped around bears’ necks, offering the first “bear’s eye view” of life in this bucolic but harsh reserve. One of the team’s main findings: These bears kill a lot more than we think they do. A whole lot more.
“It was really exciting because it’s the kind of thing you know occurs,” says Christopher Brockman, a wildlife biologist with the Alaska Department of Fish and Game (ADFG) in Palmer and lead author of the study.
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Ehsan Moqanaki once spent two years taking pictures of a cat. It wasn’t just any cat, though: It was an Asiatic cheetah, a critically endangered mammal that used to roam across lands spanning from India to Turkey and the Arabian Peninsula. In a camera-trap study published in 2010, Moqanaki and other researchers set up cameras over miles of territory in Iran’s Kavir National Park and Kavir Protected Area to try to track the number of these rare felines left in the region.
What they found was 18 photos of the same male cat, sometimes nearly 40 miles between camera trap stations. That was surprising, because the ungulate-rich region should have been great territory for the graceful and speedy cats. But Moqanaki, a researcher with the Iranian Cheetah Society and the lead author of a study recently published in Animal Conservation, suspects that the cheetah population has dwindled over time in the Kavir areas due to a lack of connectivity.
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When it comes to getting creative in the bedroom, we humans may think we’re the experts. In fact, we’ve barely scratched the surface of how varied and multifaceted reproduction can be—just look at species that do the deed through kinky-sounding strategies like sperm sequestration, “virgin births” via cloning or even hybridizing with other species. These may sound like show plots of a new series on the Space Channel, but they’re actually just some of the many tricks that Mother Nature uses to stay a few steps ahead of Cosmopolitan Magazine‘s sex tips.
Moreover, some of these unconventional methods are making scientists rethink the basic tenets of reproductive biology, says Ingo Schlupp, a professor of biology at the University of Oklahoma. His study subject, the asexual Amazon molly fish, defies the so-called rules of reproduction by making perfect clones of itself, sans males. With such a lack of genetic diversity, these finger-sized fish should have been wiped out by disease long ago, Schlupp points out.
Stress can put anyone on edge, and venomous snakes are no exception.
New research suggests that habitat loss, climate change, and other human-driven environmental stressors prompt cottonmouths to attack people more often than they otherwise would—a finding that turns a longstanding depiction of the snake as malicious aggressors on its head.
Two-headed sharks may sound like a figment of the big screen, but they exist—and more are turning up worldwide, scientists say.
A few years ago off Florida, fishermen hauled in a bull shark whose uterus contained a two-headed fetus. In 2008, another fisherman discovered a two-headed blue shark embryo in the Indian Ocean.
And a 2011 study described conjoined twins discovered in blue sharkscaught in the Gulf of California and northwestern Mexico. Blue sharks have produced the most recorded two-headed embryos because they carry so many babies—up to 50 at at time, says study leader Felipe Galván-Magaña, of the National Polytechnic Institute in Mexico.
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Having a higher rank in the social hierarchy means you get nicer things: designer clothes, a bigger house, a better iPhone. If you’re a hyena, it also means you get a better immune system. In female-dominated spotted hyena clans, females at the top of the pyramid take fewer sick days than their lowly peers, biologists report in a study published in the September issue of Functional Ecology.
The finding could offer key insights into the human immune system—and even how contagious diseases like Ebola spread among human communities. “By studying these long-lived animals, it can provide a fresh perspective on how the immune system works,” says Andrew Flies, a research fellow in immunology at the University of Tasmania and the University of South Australia and author of the new study. Flies and his colleagues examined a 30-year dataset on spotted hyenas in the Maasai Mara National Reserve in southern Kenya.
Joshua Rapp Learn 