Mike Bear had just slipped underwater, offshore near San Diego, and was floating among the long fronds of a kelp forest when a long shadow passed between him and his diving partner. Gliding by, nearly within arm’s reach, was the sleek bulk of a sevengill shark, which Bear estimated at about nine feet long.“To say we were startled would be an understatement,” Bear, a lifelong diver, says. The encounter, not uncommon among sevengill sharks, which inhabit the Pacific coast of the United State ...read more

Earth’s beautiful, neon-colored aurorae occur when charged particles from the sun (the solar wind) collide with the planet’s outer atmosphere, called the ionosphere. While this bombardment could spell trouble for Earth-dwellers, the Earth’s magnetic field lassos the particles and channels them up above the poles. Brightly luminescent, the aurorae manifest as clouds and ribbons in the sky. New research released by the Europlanet Society details the cause behind an even stranger aurora, the ...read more

By itself, Dirofilaria immitis looks about as threatening as a strand of limp spaghetti. In fact, it looks a lot like a strand of limp spaghetti. But in their hundreds, when these unassuming little roundworms grow to adulthood, they can cause serious and often fatal problems for your pet. And the worst part is, you might not see the signs until it’s too late.We’re talking, of course, about heartworms, a devastating parasite that infects about 1 in every 100 dogs. Here’s what you need to kn ...read more

Sharks are the stars of Discovery Channel’s Shark Week, starting July 23rd. They’re also critical members of our ocean ecosystems.But many of the more than 500 species of shark are endangered today as they face increasing threats from humans. Help scientists learn more about sharks, their behaviors, populations and environments, by sharing your pictures or observations from the wild, or verifying images online.Cheers! The SciStarter TeamImage credit: Project SIARCWatch underwater videos of s ...read more

Volcanic eruptions can be incredibly destructive natural disasters, covering whole cities with lava, noxious gases and ash. Plus, the seismic activity that produces them can also cause other natural disasters — earthquakes, landslides, tsunamis — that bring about further devastation.Pompeii may be the best-known ancient city to be ruined by a volcano, in part due to the exceptional preservation of the remains there. But it wasn’t the only one; and some were even larger and more central to ...read more

Female killer whales can live up to 90 years in the wild, including 22 years after they go through menopause. That’s almost as many years as human hunter-gatherers, who lived for an average of 26 years post-menopause.Aging female orcas remain an important part of their pods, but why not make them more important? Why would evolution select for such a long period in which the animals cannot pass on their genetic material? That’s the question a new study some 50 years in the making attempts to ...read more

As long as there has been life on Earth, there has been extinction. In fact, nearly every life form that has called Earth home has gone extinct.“Of the 50 billion or so species that have [lived] during our planet’s 4.5 billion year history, more than 99 percent have disappeared,” says Jessica Whiteside, a planetary paleontologist at University of Southampton.In particular, mass extinction events have shaped the course of evolution and Earth itself. This refers to relatively short spans of ...read more

Museums house thousands of animal specimens that are ancient, extinct, newly discovered and have yet to be studied. New York's American Museum of Natural History has 33 million specimens inside, while the Smithsonian's National Museum of Natural History in Washington D.C. has a whopping 145 million holdings.While most animals collected by these institutions have been obtained legally, euthanized painlessly and researched with respect, some researchers often wonder whether there could be a better ...read more

We like to think of ourselves as special. We’re Homo sapiens, after all. But a new study of Ice Age Europe has found that our supposedly unique bone tools, a sign of higher intelligence, weren’t so unique after all. Neanderthals fashioned and used hundreds of the same tools while butchering animals and preparing hides, according to a new paper.Evidence for this has arisen, in recent years, from two Neanderthal sites of some note – starting with the Chagyrskaya Cave in the Altai Mountains i ...read more

Although dirt doesn’t seem to be particularly interesting on the surface — we often picture a lifeless, unremarkable substance beneath our feet — it’s actually a dynamic ecosystem teeming with organisms. And these organisms hold the power to make or break all of life on Earth.One such unsung hero is the humble earthworm and, most importantly, its toilet habits. If you plop your spade into a patch of healthy soil, chances are that most of this is stuff that's come out the back end of an e ...read more