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What makes a top predator? Razor-sharp teeth? Speed? Strength? Size? Who is the most fearsome hunter? It depends on where and when you look.
About 100 million years ago , during the heyday of the dinosaurs, reefs were...
For a long time, scientists thought that some small tentacled fossils were...
Sirenians , or seacows, are a group of marine mammals that include manatees and...

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This early whale was well suited to life at sea. But it also may have spent time on land. An ancestor of the right whale , Maiacetus lived 49-40 million years ago. It had flipper-like limbs and webbed feet, like modern seals. But...
Offshore Peru, during the Eocene (~56-34 million years ago), showing three...
These "elevator" rudists, an ancient bivalve, used one long heavy valve to...

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Whales swim, but their ancestors walked. Whales are mammals (like us) whose ancestors lived on land. Life probably began in...
This illustration shows one old idea of what the ancient shark Helicoprion might have looked like. There once was room for many ideas—some more plausible than others—because the only fossils of the...
Where ocean currents were strong, ancient rudist “recliners” lay unattached on the seabed. Notice the pink tentacles, which were used to filter feed. Learn more about ocean life throughout deep time...
This illustration shows the edge of a warm inland sea during the Cretaceous Period, heyday of the dinosaurs. Constantly shifting sediment supported new groups of organisms, including rudist clams—...
The evolution of whales represents one of the great stories in macroevolution. It's a narrative that has mostly benefitted from an extraordinary series of fossils recovered from rocks around the...
One of the ocean's tiniest organisms often does the most harm. Microscopic algae can grow rapidly to form harmful algal blooms (sometimes called "red tides"), which create unhealthy water conditions...
The great predator Hurdia victoria’s prey consisted of trilobites and other smaller animals crawling on the seafloor.
Monodontids, the group of whales that includes the belugas and narwhals swimming our ocean today, are emblematic symbols of the Arctic. However, their fossil record, although scarce, suggests that...
A life-sized model suspended over visitors at the San Diego Natural History Museum shows what an ancient shark, the Giant Megatooth ( Carcharodon megalodon ), might have looked like. More about the...
The foot-long extinct shark Falcatus falcatus lived during the early Carboniferous period around 325 million years ago. The species, known from fossils in the Bear Gulch formation of Montana , was...
These deep-sea sediment cores were drilled from beneath the seafloor, and hold information about millions of years of ocean and atmospheric chemistry. As dirt, dead organisms, and other particles...
Rudist clams are mollusks that went extinct about 65 million years ago. They were the reef builders of the Cretaceous Period, the heyday of the dinosaurs. Today corals have taken over the role...
What makes a top predator? Razor-sharp teeth? Speed? Strength? Size? Who is the most fearsome hunter? It depends on where and when you look.
An archaeologist arranges a deep-sea core from off the coast of Britain. These cores are long cylinders of the earth's crust, drilled up from beneath the seafloor. When the cores shown here are...
The basic body plans of all modern animals were set during the Cambrian Period, 542 - 488 million years ago. Your friends, family, and pet turtle may not look much like the creatures here. But we and...
Offshore Peru, during the Eocene (~56-34 million years ago), showing three archaeocetes (ancient whales), along with a previously described fossil penguin. Top to bottom: Perudyptes devriesi ,...
The Ottoia prolifica has proven that cannibalism did exist in the Cambrian period since there have been portions of one Ottoia prolifica found in another specimen’s gut.
400 to 1,000 year old bones from an endangered seabird, the Hawaiian petrel. Bones such as these provide a window into the lives of seabirds before and after human arrival in the open ocean...
Today, filter feeders like clams, sponges, krill, baleen whales, fishes, and many others fill the ocean, spending their days filtering and eating tiny particles from the water. But when did the first...
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