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Sometimes scientific discoveries are hidden in museum specimen¹ drawers and old journal articles. In two studies in the journal Science, researchers who went through the stuff in institutional attics² offer new insights into the development and diversity of filter-feeding whales—and the fish that first occupied that ecological³ niche⁴.

It had been thought that mammoth⁵, filter-feeding fish—which swam through the water with a gaping⁶, open mouth, collecting tiny marine⁷ creatures—only lived fleetingly⁸ before whales took their place in the food chain.

But a research team decided⁹ to take a closer look at museum fossils of bony, pre-historic fish that had either been misclassified or ignored. They also reexamined previous studies.The investigators¹⁰ now say that these fish filter-feeders lived from about 170 to 65 million years ago, a healthy stretch in which to pioneer and perfect the niche.

In a related study, scientists show that when filter-feeding whales took over from bony fish, their diversity was linked to the diversity of their dinner—the tiny creatures at the very bottom of the food chain –tiny algae¹¹ known as diatoms.

New insights into some of the largest—and smallest—creatures on the planet.

—Cynthia Graber