Breeding Pandas Is Incredibly Hard

The National Zoo’s newborn panda twins are practically miracles.

Second Panda Cub
Making a historic record—only the third time in the United States—Mei Xiang delivers twins. National Zoo

Last weekend, a giant panda named Mei Xiang gave birth to two tiny cubs at the Smithsonian National Zoo. Predictably, zookeepers and animal lovers around the world were over the moon.

When an endangered species is as difficult to breed in captivity as the giant panda, even a single baby panda is a major event. Nearly 900,000 people tuned in to the National Zoo’s Panda Cam over the weekend, almost as many as visited the website in the whole month after Mei Xiang gave birth to her last baby, Bao Bao, in 2013, Perry Stein writes for The Washington Post.

Sadly, for an animal that is so beloved and yet so very endangered (there are only 1,600 giant pandas in the wild and a little over 300 in captivity), pandas don’t make it easy for the people trying to bring them back from the brink of extinction. Even as zookeepers at the National Zoo celebrated the twins’ birth, their colleagues across the Atlantic Ocean at the Edinburgh Zoo learned that for the fourth year in a row, their own possibly-pregnant panda, Tian Tian, would not give birth after all, Sam Knight writes for The Guardian. In fact, even experts weren’t sure that Mei Xiang was pregnant at all even three days before she gave birth.

So why is it so hard to get pandas to mate?

First, female pandas only ovulate once a year, Kaleigh Rogers writes for Vice Motherboard. Not only that, but the window that a male panda has to inseminate the female while she has an egg ready to go is only about 36 to 40 hours. If they miss that mark, the zookeepers have to monitor the potential mom until the next spring before she can attempt to have a baby.

Not only is the timing tricky, but the pandas themselves aren’t much help. Giant pandas evolved to be very solitary creatures and normally zoos have to keep the bears in separate pens just to keep the territorial beasts from killing each other. Not only that, but male pandas just aren’t that great at fathering children, Rogers writes.

“Our male has never really been able to breed with the female properly,” Pierre Comizzoli, a veterinarian and reproductive physiologist with the National Zoo tells Rogers. “We always offer the male a chance to breed with the female, but at some point we have to make a decision to artificially inseminate because we don’t want to miss the opportunity.”

If the male panda doesn’t know how to mount a female right, zookeepers do have the option to artificially inseminate her. Unfortunately, zookeepers usually have no idea whether the panda is actually pregnant until right before she gives birth. In fact, female pandas produce the same hormones and will act as if they are pregnant by building nests, sleeping more and eating less even if there’s no fetus, Rogers writes.

Even if a panda does get pregnant, it’s incredibly hard even for experts to find a fetus on ultrasounds. As befitting their name, giant pandas are pretty big, and their fetuses are so small that even veteran panda keepers can confuse the bear’s poop for a growing baby. Not to mention that females pandas don’t have a set term for their pregnancies: pandas can gestate anywhere from three to six months, keeping watchers on tenterhooks while they wait for a sign, Christine Dell’Amore writes for National Geographic.

But even if all goes well and the female panda does get pregnant and carry her baby to term, the infant panda is completely, absolutely helpless for the first two weeks of it’s life. As soon as Mei Xiang gave birth to her twins, keepers at the National Zoo started a 24-hour program to keep watch over the cubs, alternating custody of the baby bears with their mom every three hours.

Unfortunately, Mei Xiang herself got in the way of their plans: as of August 25, the mother bear was refusing to trade the larger of her babies for the smaller one, Beth Py-Lieberman writes for Smithsonian Magazine. At 2 p.m. on August 26, officials at the National Zoo announced in a statement that despite their best efforts, the little cub died, Jessica Durando reports for USA Today.

“We are still in a really critical period of time because the cubs are extremely vulnerable and fragile,” Comizzoli tells Rogers. “Three years ago we lost a cub at the age of six days because there was a malformation.”

With everything that can go wrong, it’s no wonder that newborn pandas are such a big hit.

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