Neanderthals are often portrayed chowing down on mammoth meals and woolly rhino ribs. But an analysis of their leftovers from a coastal cave in Portugal suggests fish and mollusks claimed a special place on their Paleolithic palates.

“We all have that image of the primitive Neanderthal that eats lots of meat,” said Filipa Rodrigues, an archaeologist at the University of Lisbon and author of a paper published Thursday in Science. “Now, we have this new perspective that they explored the marine resources like Homo sapiens did.”

Archaeologists have previously found evidence that Neanderthals ate, collected and wore jewelry fashioned from shellfish. But evidence they consumed large amounts of fish has been lacking. Some scientists have argued Neanderthals did not have the skill or wit to catch fish as their Homo sapiens contemporaries did in Africa, and may have lost out on consuming aquatic animals rich in fatty acids that could have aided with brain development.

But deep in Cueva de Figueira Brava, which housed Neanderthals about 100,000 years ago, Dr. Rodrigues and her colleagues have uncovered more than 560 fish bones, as well as remains from clams, mussels, crabs, waterfowl, seabirds, seals and dolphins. The findings suggest Neanderthals cast a wide net to add sea creatures to their dinner menus, and the researchers say it shows the behavior of the archaic species was comparable to modern humans that lived at the time.