MS. REBECCA SHEIR
And while we're talking about sex, we move to another and very different story about sex and communication. This one involves the mysterious signals panda Mei Xiang has been sending scientists at the National Zoo.
MS. REBECCA SHEIR
Now, you may remember environment reporter, Sabri Ben-Achour's report earlier this year about how hard it is for pandas to have babies the old-fashioned way. And that's why folks at the zoo usually have to go give them a helping hand, so to speak.
MS. REBECCA SHEIR
Well, those folks are biting their fingernails right about now as they try to determine whether Mei Xiang is indeed pregnant. She's sending them a lot of signals, but it's kind of hard to figure them out. Sabri brings us this update on "Panda Pregnancy Watch 2011."
MR. SABRI BEN-ACHOUR
As usual, a crowd is gathered around the panda exhibit at the National Zoo. Nine-year old David Oleman is practically climbing over the gate.
MR. DAVID OLEMAN
They're cool animals. This is my first time I've ever seen one and they're cool.
He'd really like to see a baby panda.
I've seen one on TV and they're pretty cute. They're really curious. They look like a regular panda except a lot smaller and I like seeing them play.
Brandy Smith would like to see a baby panda. She's senior curator here and she is standing in front of a wall of computer screens at what's basically the zoo's panda master control center.
MS. BRANDY SMITH
Mei Xiang is our female giant panda and she is on the monitor on the right and we are looking at what we hope is pregnant female giant panda.
Mei Xiang is sprawled out over a rock doing a whole lot of nothing. She was inseminated at the end of January and she may or may not be pregnant because with pandas, you never really know.
You don't. So that's the complicated thing. Pandas either are pregnant or they go through something a pseudo pregnancy. And in a pseudo pregnancy, almost everything is the exact same as if she were having a baby.
Her hormones are the same so we track her hormones every day. Her uterus develops, the wall thickens as if she were pregnant and she becomes very lethargic, very tired. So she does all of these things whether she's pseudo pregnant or pregnant.
Nobody knows why this is exactly, but it's some kind of hormonal consequence of panda's annual ovulation and just like in humans, Mei Xiang's behavior changes during this time.
Comparing pandas to humans, or at least the ones that I've known, she's not crabby when she's pregnant, but she's spacey so she's kind of, you know, a spacey panda. She's got this look in her eyes that says she's not quite engaged with us and the world around her. She's just a big lump of panda at this point.
Mei Xiang is getting pickier with her food, too.
There's very little that can get her to move so we can train her. So at this point, we have a panda who will only work for pears.
Mei Xiang is even kind of getting a nursery ready.
She builds a nest, which she does out of bamboo. She shreds bamboo in her den. There's another thing that she does, which I think is absolutely adorable, she cradles her toys. She actually cradles them. She tends to them and cradles them and she's doing that now, which is just -- it's an amazing behavior.
Zookeepers have to keep close track of this because pandas don't have due dates.
You can't just count down, you know, nine months plus or minus two weeks. With pandas, it can be as brief as, you know, two to three months or it can be as long as, I think, nine months is the record.
So as Mei Xiang acts more and more pregnant, zookeepers watch more and more closely.
At this point, we do an ultrasound on Mei Xiang every day. An ultrasound on a panda is very similar to an ultrasound on a human. We go back there. We have the same ultrasound equipment.
We put gel on her belly. I guess a difference is we shave the belly of a panda where you wouldn't shave the belly of a human. We're hoping that we can see a fetus.
No luck yet. Panda fetuses are the size of a peanut. And when they're born, pandas are about the size of a stick of butter. There is one telltale behavioral sign, though, that will tell zookeepers that maybe, just maybe, Mei Xiang really will be a mom again.
The behaviors change a little bit as she approaches birth. She actually becomes restless. So right now she's very sedate, but if she were going to give birth, she becomes very restless. You know, she would start pawing at things. And once we see those behaviors starting, we'll come in and we'll be prepared for a birth.
Volunteers are watching 24/7, looking for that and the ultimate sign that Mei Xiang is really pregnant.
We will know when she has a cub if she is pregnant or not. That's the best indicator. We'll hear the squealing on the monitors.
Zookeepers estimate she could give birth between now and the middle of July, maybe. I'm Sabri Ben-Achour.
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