Why don't animals that spend most of their time naked and outdoors get sunburned? Fur, if they have it, would provide some shade. But what about toads, say, or fish that swim in shallow water? (Water absorbs some ultraviolet light, but a lot of sunburn-capable radiation travels at least a few feet beneath the surface.)

Research published in the journal eLife by scientists from Oregon State University finds that many fish, amphibians, reptiles and birds can naturally produce a compound called gadusol, which provides protection from burning rays. Until now, scientists thought that animals got gadusol only from consuming certain algae and bacteria.

"The ability to make gadusol, which was first discovered in fish eggs, clearly has some evolutionary value to be found in so many species," Taifo Mahmud, the study's lead author, said. "We know it provides UV-B protection; it makes a pretty good sunscreen. But there may also be roles it plays as an antioxidant, in stress response, embryonic development and other functions."

The same researchers also found a way to naturally produce gadusol in high volumes, using yeast. Mahmud said the discovery raises the possibility of creating a sunscreen product that humans could eat, giving them the same protection now found in rainbow trout, the American alligator and some chickens.

Dark chocolate often contains milk

Dark chocolate sold in the U.S. is often a little more like milk chocolate than manufacturers might want to admit.

An investigation by the Food and Drug Administration found that a lot of dark chocolate contains milk — even when it says it doesn't. A new consumer update elaborates on the findings, as well as the risks posed by what the agency has identified as a worrisome area for consumer misinformation. "Unfortunately, you can't always tell if dark chocolate contains milk by reading the ingredients list," the report warns.

Of the 94 total samples the FDA tested, only 6 listed milk as an ingredient. Over 60 percent of them, however, contained milk. Seventy-five percent of those that warned the chocolate "may contain milk," did indeed have dairy. Thirty three percent of those that didn't mention milk at all on the label still contained it. And 15 percent of dark chocolate samples that said they were "dairy-free" or "lactose-free" actually weren't.

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