For polar bear pregnancy tests, it’s all about the poop. Elvis the beagle is helping zoos around the country figure out if their polar bears are pregnant, and he gets it right 97 percent of the time. But Elvis has never met a polar bear. Instead, he sniffs samples sent to him from zoos around the country, anxious to know whether they can expect a little cub or not.
A chocolate Labrador retriever named Papa Bear and a golden retriever named Bretagne are even trained to let diabetics know when their sugar levels are too high or too low, according to ABC News.
But when Kansas-based dog trainer Matt Skogen received an email from a conservation expert at the Cincinnati Zoo asking him to help figure out if the zoo’s polar bears were pregnant, he was caught off guard.
“A zoo in the Midwest, polar bears, pregnancies—when I first received that email, I really was a little skeptical as to the validity of it,” he says. “I get some doozies, and this is right near the top.”
Dog owners have long suspected that their dogs can tell if the owner is pregnant, but there’s never been a study to prove the suspicion, Skogen says. The pet pooches are likely just reacting to a general biological change in their owner, unless they were specifically trained to detect pregnancy. That’s unlikely, since this is the first time Skogen knows of a dog being professionally trained for the task.
Polar bears only give birth about five times in their lives, and they usually only have or two cubs in each litter—a fairly low birth rate when compared to other mammals, like dogs, that can have more than a dozen offspring in a year or cats, which can have 14 kittens in a single litter. The bears mate in the spring, but females only release an egg, or ovulate, during intercourse.
Even then, there’s no guarantee that the egg will be fertilized—it can take a few tries. If a female does get pregnant, she will gain about 250 pounds during her eight-month pregnancy. Cubs weigh about a pound when they’re born.
The thing is, zoologists can’t always tell if a polar bear is pregnant because females often become “pseudopregnant.” The bears show all the signs of pregnancy after mating, like weight gain and even nesting behavior, but come December, there’s no baby cub. The San Diego Zoo reports that this isn’t just a problem with bears—it also happens with mice, dogs, and even humans. The hormones in pseudopregnant and pregnant bears are close enough to throw off lab-based pregnancy tests.
And so, at zoos across the U.S., the staff must resort to waiting, setting up cameras and monitoring the dens 24/7 to see if their polar bears will give birth. But last year, only three polar bear cubs were produced in U.S. zoos, two of them in Toledo, Ohio.
Erin Curry, who works with the Center for Conservation and Research of Endangered Wildlife in Cincinnati, thought there had to be an easier approach than waiting anxiously. Training a dog to help them detect the pregnancies might be a long shot, but it was worth a try.
“This is the first time sniffer dogs have been used in biomedical research as it relates to any wildlife species, making this project truly one of a kind,” she said in a statement.
Getting Down to Business
Dogs are so good at this kind of detection because of their heightened senses. In a recent Bloomberg Businessweek article on bomb-sniffing dogs, writer Josh Dean explained:
Dogs sniff five times a second, and each nostril pulls in a separate sample, which helps them find the direction of a scent’s source. The dog’s nasal physiology differentiates between air for breathing and air for sampling; the latter is diverted through an olfactory organ that only scent-driven animals have (rodents being the other leading example), where receptors hang from a layer of tissue known as the olfactory epithelium like electrical fixtures from a ceiling. A scent dog has as many as 300 million of these receptors, compared with 5 million in humans. Thirty-five percent of a dog’s brain is dedicated to smell.
For the project to work, Elvis would never actually meet a polar bear. Instead, he would concentrate on their poop. Of the more than 2,000 proteins in polar bear fecal samples, only five are consistent with pregnancy, and he’d be sniffing for those.
The training process was bumpy at first. Skogen started out with two dogs—Elvis and a border collie. Both were trained using more than 200 samples from polar bears that had already given birth. The trainer created a wooden board with holes in the top and canisters underneath containing one test sample each.
Skogen soon decided to concentrate on Elvis because the other dog was guessing too often. After a few months “where he was truly in a fog,” Elvis started to really get it, the trainer said. Skogen then added samples from male bears to test Elvis’s ability to decipher between pregnant and non-pregnant bears.
The trainer remained skeptical until one day in mid-April, when it became impossible to deny Elvis’s skills.
“We’re sitting there mixing and matching, throwing every curveball you can imagine at this little guy, and he’s consistently finding the target odor,” said Skogen. “It was pretty amazing.” When the beagle identifies a positive sample, he is trained to sit, pointing his nose at the sample. Elvis is then rewarded with his favorite treats.
In the most surprising case, Elvis identified a pregnancy in a sample that zoologists had labeled as negative. Skogen thought Elvis was tripping up, but he called Curry to double check.
She went back into the records, and it turns out that a few months after the sample was collected, the polar bear had in fact given birth to a cub. There was no getting it past Elvis.
“That was a great thing,” Skogen said with a laugh. “Here we thought we had a rouge alert, but it ended up being very positive.”
Today, Elvis is identifying pregnancies with a 97 percent accuracy rate—that’s better than many at-home pregnancy tests are at alerting humans.
This month, he’s busy testing 34 samples, two each from 17 polar bears at 14 zoos across the U.S. and Canada.
By the end of the test, those zoos should know whether to expect a fuzzy little bundle of joy this holiday season.