MELISSA BLOCK, host:
An animal quiz now. What do you think is making this sound?
(Soundbite of cheetahs chirping)
BLOCK: A bird? Maybe a gecko? No, that chirping is coming from baby cheetahs, fuzzy, grayish-gold cubs with dark spots on their legs and bellies and oversized claws
Ms. ADRIENNE CROSIER (Cheetah Biologist, Smithsonian Conservation Biology Institute): She was growling at me the other day, which was very cute. She's four pounds of fury.
BLOCK: They were a little over a month old on the day I visited them.
Ms. CROSIER: She looks good, no nasal discharge. Her eyes look clear.
BLOCK: The cubs are getting their daily weigh-in, plunked into a kind of measuring cup on a digital scale.
Ms. CROSIER: 2.15 kilograms. Good. She must have had a good lunch.
BLOCK: And am I crazy, or does her face look more female, more feminine?
Ms. CROSIER: I think it does, too.
(Soundbite of laughter)
Ms. CROSIER: So yeah, she has a very dark, little, petite, feminine face, yeah.
BLOCK: These cubs were born 10 days apart at the Smithsonian's Conservation Biology Institute in Front Royal, Virginia. And here's what's unusual: Even though they're not siblings, these baby cheetahs are being raised by the same mother. It's called cross-fostering.
Ms. CROSIER: Which actually hasn't been done very often in North America. This is only the sixth time.
BLOCK: That's cheetah biologist Adrienne Crosier. She explains that if a cheetah gives birth to a single cub, she won't produce enough milk, and the cub will die. So when the first cub was born, a male singleton, they took him away from his mother and started bottle-feeding him.
Ms. CROSIER: Really, there was not much of a choice in our minds that that was the best thing for the cub because we absolutely wanted him to be able to survive.
BLOCK: What was lucky was that another adult cheetah, nine-year-old Zazi, gave birth to her own female cub soon after. So the Smithsonian staff decided to take a chance. They'd see if Zazi could be a foster mom, raising both cubs together. It was a gamble. The mom could have rejected the cub, maybe even killed it, says lead cheetah keeper Lacey Braun. So the staff tried a few tricks.
Ms. LACEY BRAUN (Cheetah Keeper, Smithsonian Conservation Biology Institute): The night before we did put the cub with her, we put the cub in shavings with her smells. So we did already introduce her smells onto the new cub. So we might have tricked her a little bit.
BLOCK: Do you think that made a difference, having that scent on the cub?
Ms. BRAUN: Yeah, and we rubbed the cubs together, as well, so...
BLOCK: You rubbed the cubs together?
Ms. BRAUN: Just to get the other cub's smells on the new cub, so it's kind of like already her cub.
BLOCK: And it worked.
Ms. BRAUN: She was amazing. She took right to the new cub and just groomed it right away and accepted it willingly.
Ms. CROSIER: You know, she seemed to be just fine with having a second cub in there and was nursing them both within about an hour.
BLOCK: Why is it better to cross-foster, do you think, the way you are with these two cubs than to raise one by hand, just to bottle-feed one?
Ms. BRAUN: Cubs being mother-raised are so much easier to breed in the future than being hand-raised. A hand-raised cub just doesn't know how to communicate with the other cheetahs, basically, and is harder to breed.
BLOCK: What happens? Why do you think that is?
Ms. CROSIER: I think a lot of hand-raised cheetah cubs, when they become adults, they're still very bonded to humans. And the socialization that they have is stronger toward humans rather than other cheetahs, and they often don't show sexual interest in cheetahs of the opposite sex.
BLOCK: And breeding is the first priority. The wild cheetah population is designated as vulnerable to extinction. Over the last 100 years, the numbers have declined by almost 90 percent, from about 100,000 to 12,000, mostly in sub-Saharan Africa.
So these cheetahs in Virginia are a hedge against extinction. The more research scientists can do on cheetahs in captivity and the more genetic diversity they can build, the better equipped they are to save the wild species.
But for now, for these two young cubs, all that is far in the future. For now, it's all about small steps.
Ms. CROSIER: There he goes. He's out. Oh, gosh.
(Soundbite of laughter)
BLOCK: The cheetah cubs are living in a small shed with mom, who was put outside for our visit. Adrienne Crosier and Lacey Braun only spend a few minutes a day inside the shed, but they watch over the cubs all the time through their cheetah-cam.
And on this day, as they watch on a monitor, the male cub thrills them. He toddles up to the edge of the nest box and steps out, his first taste of independence. Zazi, the mom, follows close behind.
Ms. CROSIER: There she goes.
Ms. BRAUN: She'll pick him up and put him back in the nest box.
Ms. CROSIER: She's trying to figure out where she wants him as much as he's trying to figure out where he wants to go
Ms. BRAUN: And where he wants to go is out.
Ms. CROSIER: Oh, he's going again.
(Soundbite of laughter)
Ms. CROSIER: Oh, he's such a stinker.
BLOCK: And Michele, I can tell you since we were out there in Front Royal, Virginia, the female cheetah cub has also made the big leap outside the nest box. We hear that both of them now are really active, running around their shed and playing with each other all the time.
MICHELE NORRIS, host:
Well, you know, here in the studio, I'm actually watching the cheetah-cam here on the computer, and I invite people to think about doing this at home, as well, because they are so adorable, and they're so teeny.
BLOCK: They are very teeny. They are extremely cute, hard to resist, no names, yet, though, just called Little Boy and Little Girl.
NORRIS: And remember if you want to watch this at home, go to npr.org.
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