Photograph courtesty Rafael Reyna

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The rare giant forest hog makes an appearance on this week's most intriguing news stories.

Photograph courtesty Rafael Reyna

This Week’s Most Intriguing Discoveries

King Tut's unsolved death, shrinking mammals, and giant pigs make our list of the week’s key discoveries.

It's been a busy week at National Geographic.

From a rare hybrid solar eclipse to an important debut swim for a pair of tiger cubs, we covered it all. The week’s five key discoveries:

1. Global warming made mammals smaller. Researchers looked back 56 million years, to when the Earth's temperatures spiked six degrees Farenheit, and noticed that mammals were smaller versions of themselves during the heat wave. The Hyracotherium, a now-extinct horse, evolved to be about 30 percent smaller. Dwarf mammals could have had higher skin-to-body ratios, making sweating easier and overheating less likely. Once the heat wave was over, the mammals rebounded to "normal."

2. Meet the world's biggest pig. At 600 hefty pounds, the giant forest hog would make quite the roast. But that's the problem: The world's biggest undomesticated pig has become endangered due to hunting. Conservationists are trying to step in and protect the gentle giants in Kibale National Park in Uganda.

3. Being a night owl might make you sick. Don't want to put that best seller down and turn off the light? There could be a serious downside. Stay up later and risk being sick, says a study that shows your body's circadian clock is closely attuned to your immune system. Instead of scrolling through your Instagram feed just before you doze off, give your brain a break and teach it to expect sleep by closing the curtains and shutting off lights.

4. If you want to feel better, wash your hands. (Warning: You might also wash away motivation.) Kai Kaspar at the University of Osnabrück published a study showing that washing hands after you failed at a task made you feel better. But—and it’s a big but—you're less motivated to try harder next time. Researchers think it's a mental "wash your hands of sin" sort of ritual that helps you get past a recent failure. But if you're hoping to improve on that tough task, stay dirty.

5. King Tut might have burst into flames. Or not. Britain's Channel 4 will air a TV program on Sunday that features controversial evidence that King Tutankhamun's mummified body was burnt. Egyptologist Chris Naunton thinks that burnt flesh is an indicator that King Tut's body spontaneously combusted from a mummification gone wrong. National Geographic's A.R. Williams delved into the mystery and raised questions about the fiery theory. Why does the jewelry the boy king wore in his sarcophagus bear little, if any, fire damage? Why were the wooden outer coffins unmarked by scorch marks? Either way, the mystery of the boy wonder's death continues.

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