Cheetahs: animal world's Ferraris

(Reuters) - Cheetahs can aptly be called the race cars of the animal kingdom: sleek, graceful and supremely speedy.
Scientists have now taken a look under the hood of these feline Ferraris to gauge how much energy they burn as they traverse their African habitats and to gain insight into factors that may be contributing to their population plunge.
A study published on Thursday in the journal Science described how researchers tracked 19 free-roaming cheetahs for two weeks at two sites in South Africa and Botswana. They measured energy expenditure after injecting cheetahs with isotope-laden water and later analyzing their feces.
They were surprised to learn that cheetahs used relatively little energy in their high-speed chases for prey like gazelles and impalas. The world's fastest land mammals, known for their spotted coat, cheetahs accelerate from a standstill to 96 kph in three seconds.
The findings contradicted the hypothesis that cheetahs spend a large amount of energy catching new prey after bigger competing predators like lions and hyenas steal carcasses brought down by them.
Their biggest energy drain is the distances cheetahs must walk while seeking prey thanks to man-made problems like habitat loss in grasslands, fences restricting free travel and people killing too many of the animals cheetahs eat.
Queen's University Belfast biologist Michael Scantlebury, who led the study, said the cheetahs travel up to nearly 30 km per day. He said "Cheetahs may be Ferraris but most of the time they are driving slowly," moving over sand dunes in baking heat with no water to drink.
Cheetah populations have declined from about 100,000 to 10,000 over the past century, experts say.
"Humans are responsible for their dwindling numbers. We need to be more careful and maintain the remaining areas of the world that are truly wild. We must think about the consequences of our actions," Scantlebury said.

edited from Reuters

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Hong Kong protesters use FireChat app

Many of Hong Kong pro-democracy protestors are messaging one another through a network that doesn't require cell towers or Wi-Fi nodes. They're mesh networking, using an app called FireChat that lets phones unite to form a temporary Internet. Mesh networks are effective and quickly adopted during times of disaster or political unrest, as they don't rely on existing cable and wireless networks. In Iraq, tens of thousands of people have downloaded FireChat as the government limits connectivity in an effort to curb ISIS communications. Protestors in Taiwan this spring turned to FireChat when cell signals were too weak and at times nonexistent. And FireChat's popularity is surging in Hong Kong. About 100,000 users downloaded the free FireChat app between Sunday morning and Monday morning. Hong Kong student leaders are recommending FireChat for fear authorities may shut off communications. Mesh networks are an especially resilient tool because there's no easy way for a government to shut them down. They can't just block cell reception or a site address. Destroying one part won't kill it unless you destroy each point of access; someone would have to turn off Bluetooth on every phone using FireChat to completely break the connection. This hard-to-break connection isn't super important for casual chats, but during tense political showdowns, it could be a lifeline. FireChat has a "nearby" function enabling communication with people in the same vicinity. Chats are organized by theme and you can see everyone's location. Open Garden, the company that made FireChat and an Android mesh networking app also called Open Garden, has bigger ambitions for mesh networking: "Once you build a mesh network, you have a network that is resilient, cannot be controlled by any central organization, cannot be shut down and is always working," Christophe Daligault, Open Garden's vice president for sales and marketing says. "None of this would be possible without the rapid spread of smartphones, because that means no extra hardware is needed. Each phone becomes a router and in a sense you're growing the Internet — everyone who joins the mesh network creates an extension of the Internet. In a year or two from now, I think people won't even remember that you had to be on Wi-Fi or get a cell signal to be able to communicate." One problem with FireChat is that all messages are public. Staff at Open Garden have warned users about this and urged them to use pseudonyms. "We hope FireChat will serve you well," Open Garden wrote in a Facebook post. "Please remember messages are not encrypted at this point. Please be cautious about what you say and do not use your real name."

edited from ABC and NPR

Why is Hong Kong protesting against China? (video)

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