CURWOOD: This is Living on Earth. I'm Steve Curwood. A handful of scientists around the world are leading the high-tech effort to keep the planet's most endangered animals from going extinct. These reproductive physiologists encounter failure far more often than success, but when success does come it can mean headlines. One of the leaders in this field is Dr. Barbara Durrant of the San Diego Zoo. From member station KPBS in San Diego, reporter Erik Anderson has this profile.
ANDERSON: Behind the scenes of the giant panda exhibit at the San Diego Zoo, keeper Dallas Ripsky pulls down a large metal latch, opening a door to a car-sized cage on wheels.
ANDERSON: She urges the zoo's female panda to enter.
RIPSKY: Come on, buddy.
ANDERSON: The 215-pound Bai Yun waddles into the squeeze cage, sniffing for the apple and carrot snacks that she knows are coming. This morning, Ripsky has company.
RIPSKY: Hello, Barb.
ANDERSON: Since the giant pandas first arrived from China four years ago, Barbara Durrant has been a regular visitor. This morning, she's here to check in on the first-time mom. Barbara and Dallas use a noisemaker and the lure of food to position the black and white bear.
RIPSKY: The other way.
DURRANT: Over here.
RIPSKY: No, that's not the way we do it now.
DURRANT: Well, we're going to do it this way today.
ANDERSON: Bai Yun sits up and eagerly accepts a freshly-cut carrot. Durrant kneels at the side of the cage. She has no trepidation about putting her hands inside, even though the seemingly cuddly animal sports huge claws and formidable teeth. Durrant is here to collect a pap smear. She puts a medical Q-tip on the end of a glass tube and reaches into the cage. Bai Yun is sprawled on her back with feet spread. The panda is far more interested in the carrots than helping Durrant.
DURRANT: Down. All the way down. I'm going to strap that leg to the side of the cage. (Ripsky laughs) We could use some stirrups. Be all the way down.
RIPSKY: Nope, nope, nope. Doggone it, she got it again. All right, let's try one more -- okay, I think I can - this one's okay.
ANDERSON: Durrant says the birth of Bai Yun's cub Hua Mei in 1999 was the highlight of her scientific career. Captive births are crucial for the future of the black and white bears because habitat destruction has reduced the number of wild pandas to less than a thousand. Her colleagues jokingly call her Hua Mei's dad, and last year she got cards on Father's Day. That's because Durrant was responsible for harvesting sperm from the reluctant male Shi Shi and artificially inseminating Bai Yun at precisely the right moment. No small feat, considering that pandas go into heat only a few days each spring. In tribute to that accomplishment, Durrant's ordered but cramped office, which she shares with several of her technicians, is filled with panda knickknacks. But it's a small handful of gag gifts that quickly draw a visitor's eye. A ceramic sperm bank. A wind-up sperm toy. And a small brass statue of two rhinos locked in a mating embrace.
DURRANT: I've been a reproductive physiologist for 21 years, and there is absolutely nothing that anyone can say that will embarrass me any more.
ANDERSON: But that wasn't the case when she arrived at the zoo as a young and shy postdoctoral researcher in 1979. Back then, she says mischievous animal keepers did everything they could to embarrass her, and they succeeded. Now, Durrant keeps things in perspective.
DURRANT: Collecting semen from a bull elephant, for instance, is very serious business, and also a little frightening. But when you go back and review the photos that people have taken while you're very earnestly doing this procedure, you find that you have to laugh. It's pretty ridiculous.
ANDERSON: That's one reason she can talk candidly about her latest project with the giant pandas. Recently, she's been working with Shi Shi in hopes of collecting a sperm sample, much the way she does with some of the zoo's other endangered animals, without anesthesia. Back at the panda exhibit, keeper Dallas Ripsky calls out to the aging male.
RIPSKY: Come on, Shi Shi! Shi Shi! (Bangs on drum) Good boy, you Mr. Smarty-Pants. Come on!
ANDERSON: Shi Shi plops down and watches as Durrant pulls out a small medical vibrator.
DURRANT: Hear this?
RIPSKY: Has he ever touched it with his nose?
RIPSKY: What did he do?
DURRANT: Nothing. (Laughs)
RIPSKY: Already doing the Indian seat.
ANDERSON: Shi Shi hasn't responded yet, but Durrant hopes that will change. That's because there's always a risk when an animal is anaesthetized. So right now, Durrant is only able to harvest panda sperm when vets knock the bear out for a medical procedure. That's particularly frustrating because the aging Shi Shi holds a special place in the captive panda community.
DURRANT: Genetically, he's very, very valuable, because he's a wild-caught animal. He would be known as a founder animal. It's the assumption that we have to make that they are the most genetically diverse.
ANDERSON: The giant pandas have landed most of the headlines, but Durrant's work doesn't stop there. She's helped bring hundreds of threatened species into the world, including rhinos, birds, snakes, and cheetahs. In fact, the San Diego wild animal park's cheetah breeding program is one of the most successful in the world. At the cheetah compound, a handful of cats are lounging in the midday sun. Large wire-enclosed pens surround a small stand of thatch-roofed buildings and trailers. Keeper Therese Everett has just mixed a specially-enhanced meal for one of the pregnant cats, and with food in hand it only takes a moment to get the cheetah's attention.
(Durrant whistles, a gate clanks open. The cheetah purrs)
DURRANT: Yeah. You a hungry girl? Wait. Okay. Good girl.
ANDERSON: Keepers, veterinarians, and Durrant are working together to maximize the cats' breeding cycles. Because their numbers in the wild are dwindling, there is a sense of urgency to bringing new cheetahs into the world. The team says it can't rely on natural breeding patterns because they don't guarantee conception.
ANDERSON: Near the center of the compound, where an industrial-sized outdoor refrigerator hums in the background, Durrant leans over a row of wooden crates. Always looking for a better technique, she's now in the process of trying out a new cheetah breeding box. It's a handmade wooden crate that stands about three feet tall. One side is open and the other closed, except for a small hole.
DURRANT: And someone will be dropping cheese down through this hole.
ANDERSON: The food will keep the cheetah busy and minimize risk to keepers.
DURRANT: He'll be preoccupied with eating the cheese, and then we can come around this way and put an artificial vagina on him.
ANDERSON: Durrant says each animal has to be treated as an individual. For instance, there is a mandrill at the zoo that has developed, shall we say, an interest in humans with a certain hair color. When keepers visit him for a sample collection, they make sure there is a blonde in the crew for the baboon to focus on. Durrant says you can tell a lot about her life by her first memory. It's of the family dog. That early affinity for the animal world was with her as she grew up and wandered the wooded hills of upstate New York. Her passion eventually led her to study animal science in college.
DURRANT: That's all about domestic animals, which I also like, but I couldn't see myself working to increase reproduction in domestic animals just then to send them all to the slaughterhouse.
ANDERSON: She says it was her first look at a microscopic mouse embryo that cemented her desire to become a reproductive physiologist. Despite her groundbreaking research with many endangered species at the zoo, Durrant is likely to be remembered publicly for her work with giant pandas. Her scientific legacy, however, is much larger. But it's located in a small room near her office. There, she keeps a modern version of Noah's Ark.
DURRANT: This is the frozen zoo. It's a little cold in here. We like to keep it that way. But the freezers also keep it that way. You can see a large tank outside the window, and that's our store of liquid nitrogen.
ANDERSON: The nitrogen cools eight waist-high freezers that ring the small chamber. Durrant leans over and unseals the top of one of them.
DURRANT: You have to be very strong. There.
ANDERSON: As she lifts one of the garbage can-sized lids, a six-inch-deep fog covers the room's floor.
DURRANT: Inside we have these racks, these aluminum racks. And in each rack we have boxes. You can hear the liquid running off the boxes. And within each box there are 100 samples.
DURRANT: I have to put this right back down into the liquid because you don't want these samples to be, to warm up.
ANDERSON: The samples represent sperm and eggs for more than 250 endangered species. Durrant uses some of them for her current reproductive work. But perhaps more importantly, she's also using part of each sample to develop methods to safely freeze, store, and thaw each species' sperm and eggs. For instance, two years ago no one was freezing panda sperm, so Durrant had to figure out how to do it. She had to pick a solution, a cryo-preservative, to freeze the sperm in, and then work out a host of other factors.
DURRANT: How long we will cool the sample before we freeze it. How fast the freezing rate can be. How fast the thaw rate can be. And what we have to do after the sample is thawed to get that cryo-preservation out of the solution, because it's toxic to the sperm.
ANDERSON: Her frozen zoo collection is pretty impressive. With more than 19,000 samples, Durrant says there is enough material here to keep reproductive physiologists busy for decades after she's gone. Despite a career firmly rooted in the reproductive world, Durrant has no children. That may seem ironic, perhaps, until she's asked why.
DURRANT: The reason that we have so many endangered species is because we have way too many people. That is the core of every extinction that we are experiencing now: the human population.
ANDERSON: Durrant's next major project centers on the giant pandas. This spring she'll try to make sure that Bai Yun conceives again. Despite the zoo's best efforts to recreate an environment that's the panda equivalent of soft lights and music, the male Shi Shi has shown no romantic interest in his mate. That means Durrant will likely be called upon to step in where nature has fallen short. For Living on Earth, I'm Erik Anderson in San Diego.
(Music up and under: Do Make Say Think, "If I Only")
CURWOOD: This update from the San Diego Zoo: Dr. Durrant has now managed to artificially inseminate Bai Yun, the panda, a number of times this spring, but it's still too soon to tell if the bear is pregnant.
(Music up and under)
CURWOOD: Coming up: Two investigative reporters win the nation's top environmental prize for blowing the whistle on censorship by Fox TV. Stay tuned to Living on Earth.
Now this animal update with Maggie Villiger.
(Music up and under: Marvin Pontiac, "In A Big Car")
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