Dr. Universe: Why can’t sea turtles pull back into their shell? I was at the St. Louis Zoo, and they said tortoises and other turtles can pull back into their shells. – Tyler, 7, Missouri There are ...

The biggest turtle ever described wasn’t an ancestor of today’s leatherback turtles or any other living sea turtles. But it looks like there are some things about being a giant, skin-shelled sea ...

Loggerhead sea turtles migrate thousands of miles through the world’s oceans, but they don’t travel solo—research shows they carry surprisingly diverse and abundant populations of tiny creatures on ...

Around the deep-sea vents off the southern coast of Japan, a small, “glass”-like creature was discovered. Getty Images/iStockphoto Off the coast of Japan, thousands of feet below the surface, the ...