See-Through Fish



NO BONES! The skeleton of this leopard shark isn’t hard and bony. Instead, it’s made of a stretchy material called cartilage.

Marine biologist Adam Summers is on a mission: He wants to take colorful digital images of the skeletons of every known species of fish. That’s more than 30,000 species!

Summers studies biomechanics—the structure, function, and movement of living things—at the University of Washington. To better understand fish anatomy, he decided to examine their skeletons using a CT scanner. This medical-imaging machine uses X-rays, a type of electromagnetic radiation, to take pictures of structures inside the body. A computer then combines the images to create a 3-D picture.

Summers’s lab has collected about 9,000 scans so far and made them available online. Anyone can download the images, which can be used for things like scientific studies or as teaching aids in classrooms. “We felt if we could get the skeletons in the hands of researchers and the general public that they would find great things to do with them,” says Summers.


STUCK TIGHT: The northern clingfish uses the fins on the underside of its body to tightly grip rocks.