In the vast and colorful—and sometimes terrifying—world of marine life, few creatures are as captivating as the Costasiella kuroshimae. Affectionately known as the "leaf sheep" or the "Shaun-the-sheep ...

When most of us picture the ocean, we imagine turquoise waves, colorful reefs, and shoals of darting fish. But that’s only the surface. Venture deeper, far below the last reach of sunlight, and you ...

An entire world lives deep under the ocean’s surface, far from human notice and as bustling as any city. Animals such as tubeworms and clams live crowded around plumes of methane that bubble up ...