The Canadian tiger swallowtail caterpillar is a plump green creature that spends all its time munching leaves. It ought to be an easy meal for a bird, yet many birds pass it by.

The caterpillar is protected by a remarkable defense, researchers have found: It tricks birds into thinking it’s a snake.

The caterpillar grows concentric yellow and black rings that look like a giant pair of eyes. When the caterpillar senses a bird nearby, it quickly inflates the front part of its body, making it resemble a snake’s head.

Continue reading “Evolving a Defense, Mimics Save Themselves” →

You are what you eat, and so were your ancient ancestors. But figuring out what they actually dined on has been no easy task.

There are no Pleistocene cookbooks to consult. Instead, scientists must sift through an assortment of clues, from the chemical traces in fossilized bones to the scratch marks on prehistoric digging sticks.

Scientists have long recognized that the diets of our ancestors went through a profound shift with the addition of meat. But in the September issue of The Quarterly Review of Biology, researchers argue that another item added to the menu was just as important: carbohydrates, bane of today’s paleo diet enthusiasts.

Continue reading “For Evolving Brains, a ‘Paleo’ Diet of Carbs” →

Last year, scientists launched a trial of an experimental vaccine against Ebola in Guinea. On Friday, they reported great news: The vaccine works well, providing remarkable protection just 10 days after injection.

“We have to stop and celebrate the fact that an innovative trial design was able to come up, in the middle of an emergency, with pretty strong results,” said Dr. Seth Berkley, the chief executive officer of Gavi, an alliance of public and private organizations that provides greater access to vaccines in developing countries. “Let’s start with that.”

But let’s not end with that.

Continue reading “For Vaccines Needed in an Epidemic, Timing Is Everything” →

We humans can drive species toward extinction by hunting them or destroying their habitat. But we can also threaten them in a more subtle but no less dangerous way: by making them sick.

In the early 1900s, humans introduced malaria-spreading mosquitoes to Hawaii, and many native bird species were decimated. More recently, a fungus introduced to the United States from Europe has proved lethal to several species of bats.

Now, scientists and wildlife managers are struggling to prevent the next infectious disaster.

Continue reading “Importing Both Salamanders and Their Potential Destruction” →