Joel Sartore is a real-life Dr. Doolittle with a camera, or maybe a self-styled Noah.

Working with the National Geographic Society, Sartore’s long-running project—the Photo Ark—aims to “document the world’s 12,000 captive species” as a way of promoting “the message that it’s not too late to save some of the planet’s most endangered species.” So far, he’s at 5,000.

Nat Geo is hosting an exhibit of Sartore’s work—his second. The first, in 2010, was mounted in windows surrounding the society’s headquarters. This time, he’s inside, with more lavish surroundings and a more extensive selection of images.

At times, the images—made with the cooperation of zoos around the world—seem unduly manipulative due to anthropomorphism. A mandrill, a type of primate, seems to be covering a burp with a strikingly human-like hand. An arctic fox looks as tame as the neighborhood dog. A Reimann’s snake-necked turtle turns toward the camera with what looks like a goofy, sideways grin. A parent-child trio of koalas (pictured) offers an impromptu human (make that koala) pyramid.

Indeed, even a praying mantis, with a cock of its three-pointed head, becomes cute in Sartore’s viewfinder.

Sartore’s work proves its value, however, when it comes to images of nearly extinct species; these exude genuine pathos.

While Sartore’s project documents threatened and non-threatened species alike, one room of the exhibit focuses on individual animals who are literally the last, or among the last, of their species on earth, living out the agonizing wait to extinction. One, Bryn the Columbia Basin pygmy rabbit, makes a repeat appearance in Sartore’s second exhibit; the last of her species, she died not long after the photograph was taken. Another, new to the second exhibit, is a northern white rhinoceros; this one died a week after Satore’s visit, and the only four individuals that remain are not expected to reproduce.

Leavening such depressing fare is a selection of species that have recovered due to human-driven conservation, such as the black-footed ferret and the giant panda—shown in an adorable cuddle, natch. Sartore deserves credit for including a wide variety of species in his “ark,” including many that are less than charismatic, but his decision to choose the most adorable pose possibly risks overselling his otherwise admirable work.

Through April 11 at the National Geographic Museum, 1145 17th St. NW. Washington, D.C. (202) 857-7700. Daily 10-6.