just ask wildlife photographer joel sartore. >> not a bashful bird at all. ow. that'll work. there.t all fits? >> i heard about a crane getting testy with you. >> there was a hornbill that was trying to draw blood a little bit. >> done. thank god. >> reporter: it's all in a day's work for sartore's life work, his photo ark. >> the goal is to get all 13,000 or so species that are in human care. so we're about halfway done now. 6,500 so far. >> reporter: sartore's photos and how he captures them are the subject of new three-part pbs and pbs.org series "rare: creatures of the photo ark." >> you call it rare. >> mm-hmm. >> why? >> we're looking at some of the rarest creatures left on earth in this show. >> reporter: sartore and his team spent a year traveling to eight countries on five continents photographing these creatures in captivity. >> oh, man, that's nice. >> reporter: the results are these stunning portraits on black-and-white backgrounds. >> people want to know, well, why don't you do this in the wild all the time? well, you can't just walk up to animals and put a black backgr

just ask wildlife photographer, joel sartore. >> see how it all fits?u. >> there was a hornbill trying to draw blood a little bit. done, thank god. >> reporter: it's all in a day's work. his photo arc. >> the goal is to get all 13,000 or so species that are in human care. 6500 down so far. >> reporter: his photos and how he captures them are the subject of a new three-part series, rare photos of the creatures. sartore and his team traveled to five continents photographing these creatures in captivity. the results are these stunning portraits. some of sartore's images have gone viral, even projected onto major world landmarks like the vatican and empire state building. you're shopping. >> i am shopping. >> reporter: we met him at the bronx zoo where he hopes to shoot for his ark. some people will say, wait a minute, this is about seeing animals in captivity. but you see zoos and zookeepers as heroes. >> oh, yeah, they are conservation centers. for many of the species that i photograph, they only exist in zoos now. they're extinct in the wild. >> reporter

. >> joel, what do you >> i think they can elevate themselves to iconic status if they're done well enough. >> reporter: in australia sartorehis photos of injured koalas helped prompt the australian government to recognize the species as threatened. >> a group of nurses at a wildlife hospital held back, i don't know, 20 koalas that had all been killed by dogs that week. so we spread them out on a blue tarp and we photographed that. >> it's a heartbreaking image. >> oh, my god. yeah. but it speaks to koalas not being able to fend for themselves against human intrusion. so we see results. real results from these pictures. and that's very encouraging. >> reporter: sartore strarted the photo ark more than a decade ago when he was off the road taking care of his wife kathy and their three children. >> my wife got breast cancer, believe it or not, and she was on chemo and radiation for a year, and i'd never been grounded. >> reporter: his first photo was of a naked mole rat taken on the cutting board of the local cutting zoo. >> you ready? >> yeah, we're ready. >> all right. >> reporter: today hijacks family vacations to find ani