A skeleton bank of understudied species

UNDER THE SKIN

A bowmouth guitarfish cranium. DISNEY’S ANIMALS, SCIENCE, AND ENVIRONMENT VIA THE NEW YORK TIMES

An angelfish. With a new database of medical images, zoo and wildlife vets can finally see what healthy uncommon animals, from rhinos and tamarins to pangolins and sea stars, should look like on the inside. DENVER ZOO CONSERVATION ALLIANCE VIA THE NEW YORK TIMES

The tamarin monkey. DENVER ZOO CONSERVATION ALLIANCE VIA THE NEW YORK TIMES

A dolphin skull. BROOKFIELD ZOO CHICAGO VIA THE NEW YORK TIMES

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By Emily Anthes

The New York Times

Woe betide the rhinoceros radiologist.

“Radiologists are very comfortable with dogs, cats, horses, cows,” said Dr. Michael Adkesson, the president and CEO of Brookfield Zoo Chicago.

But ask them to peer inside a critically endangered, 2,300-pound black rhino and they might quickly find themselves in uncharted territory. In 2018, after one of the zoo’s rhinos developed hard-to-diagnose breathing problems, Adkesson and his colleagues managed to take a CT scan of its head — and then found themselves wondering what the inside of a rhinoceros head was even supposed to look like.

“With zoo and wildlife animals,” Adkesson said, “we often just don’t have good reference data available.”

In an effort to solve this problem, Adkesson and his colleagues built the Zoo and Aquarium Radiology Database, which was unveiled last month.

The online database, a collaboration between seven zoological institutions, contains more than 1,000 medical images — X-rays and CT scans — of 50 different species, including the greater roadrunner, the cotton-top tamarin and the bowmouth guitarfish, also known as a shark ray. The goal is to have more than 10,000 images of 500 species by 2026.

Many of the images in the database, which all depict healthy animals and were reviewed by board certified radiologists, were produced in the course of providing routine care for zoo denizens.

But there is nothing routine about imaging rare and exotic animals, which may require moving anesthetized rhinos with front-end loaders, persuading giraffes to present their hooves and propping up fish on wet sponges.

“If you’ve got a bucket, and you can keep a stingray in a little bath of water, you can image the entire bucket with the stingray in it,” said Dr. Eric Hostnik, a veterinary radiologist at the Ohio State University and the lead radiologist for the project. “You’ll still get great images.”

The team hopes that zoo veterinarians will incorporate the database into their everyday practice, consulting the reference images when they spot something strange on a snake’s CT scan, or find themselves puzzling over why a pangolin looks peaked. “Your general veterinarian can open a number of textbooks and look up cat and dog stuff,” Hostnik said. “The same isn’t as true for our zoo vets.”

It could also be a resource for field biologists studying vulnerable populations in the wild, Adkesson said, or even yield new insights into the basic biology of understudied species.

And even for nonexperts, the images lay bare the astonishing diversity of animal bodies that have evolved on Earth. Sea stars have no backbones, while snakes are almost all spine. A stingray’s skeleton is made entirely of cartilage. Anteaters and pangolins, which slurp down insects with their long tongues, are among the few mammals without teeth. (A pangolin’s tongue, and the bone it is attached to, extends down through its chest.)

“The beauty of some of that anatomy is so striking,” Adkesson said. It’s not always easy for the public to appreciate, he added, “until you start looking at a skeleton.”