Category — Polar Bears
Elvis has spent the past three weeks sniffing fecal samples from polar bears around the country, making his predictions on which bears might be pregnant. Elvis is trained to pause and sit immediately when he detects a pregnancy—and does not show interest at samples from non-pregnant bears. Last week, Elvis was presented multiple times with two separate samples (collected on 10/12/13 and 10/20/13), from the Cincinnati Zoo’s female polar bear, Berit. Unfortunately, Elvis did not show interest in either sample, indicating she may not be expecting cubs this fall.
The sniffer dog project is part of a larger effort to study reproduction in polar bears. Scientists at CREW have been monitoring polar bears since 2008 and have analyzed over 14,000 fecal samples from 55 polar bears living in North American zoos. In addition to the Elvis test, we’ve been measuring Berit’s fecal hormone levels and performing ultrasound examinations in attempts to gain more information about her pregnancy status. Taken together, it seems that Berit is probably experiencing a pseudo-pregnancy, also known as a false pregnancy. Pseudo-pregnancy occurs when a female’s hormones, namely progesterone, increase to levels similar to those of a true pregnancy. However, in a pseudo-pregnancy, no fetus is present. Like pregnant bears, pseudo-pregnant females often gain weight (Berit gained almost 200 pounds this season!) and may behave like they’re pregnant, building nests and spending more time in their dens.
We’re not sure why pseudo-pregnancy occurs in polar bears but it seems to be a common phenomenon in many females we’ve monitored. A goal of CREW’s polar bear research is to develop a test to differentiate pseudo-pregnancy from true pregnancy. If Elvis proves successful, the next step is to identify the specific compound in the fecal samples that Elvis is signaling on and then develop a laboratory-based method to measure it. A test that distinguishes pregnancy from pseudo-pregnancy could potentially be applicable to other species that experience pseudo-pregnancy, such as endangered cat species, otters, and red pandas.
Since the sniffer dog project is still in the testing phase, we are not making any major management changes based on Elvis’s predictions. Berit’s keepers continue to keep a close eye on her and she still has access to a den and extra bedding if she wants it. Berit has never produced offspring, so while Elvis’s predictions are disappointing, they are not a total surprise. Berit is of prime reproductive age for a polar bear (14 years) and we have not lost hope that she may have cubs next year!
November 19, 2013 1 Comment
Over the past two weeks, Elvis the pregnancy diagnosing beagle, has been hard at work smelling fecal samples (yes, fecal samples) collected from 17 female polar bears, including the Cincinnati Zoo’s own female, Berit. Currently, there is no definitive test for pregnancy in polar bears, so Elvis has been trained to identify samples that originated from pregnant females in an effort to predict which females are due to have cubs in a few weeks. Last week, Elvis demonstrated an impressive 100% accuracy on the known ‘test’ samples he had never smelled before, signaling appropriately on the pregnant samples while ignoring those that came from non-pregnant individuals.
We humans don’t yet know exactly what Elvis is smelling that enables him to identify the samples from pregnant bears. In his early training, he was exposed only to samples that came from pregnant bears. Over time, other samples, such as those from males and from juveniles were introduced, but he was only rewarded when he signaled on the pregnant samples. Eventually, samples from females in estrus and females known not to be pregnant were thrown in the mix. After months of training, Elvis has seemingly figured out what makes the samples from pregnant females different from all others.
A dog’s sense of smell is incredibly powerful- Elvis possesses around 225 million olfactory (smell) receptors in his nose, compared to just 5 million in a human’s. Dogs also make better use of another olfactory organ, Jacobson’s organ, allowing them to detect pheromones which are other chemical communicators of physiology (and possibly pregnancy?). Additionally, the part of a dog’s brain dedicated to analyzing smells is 40 times greater than ours. As a result, a dog’s sense of smell is 10,000 to 100,000 times better than that of humans.
“If you make the analogy to vision, what you and I can see at a third of a mile, a dog could see more than 3,000 miles away and still see as well” said James Walker, former director of the Sensory Research Institute at Florida State University.
Put another way, while we would probably notice if our coffee has a teaspoon of sugar added to it, a dog could detect a teaspoon of sugar in a million gallons of water, or two Olympic-sized pools worth, according to Alexandra Horowitz, a dog-cognition researcher and author of Inside of a Dog.
Because their noses are so sensitive, precautions need to be taken so we don’t inadvertently compromise the results. Samples are double-bagged and stored separately to make sure scent cross-contamination doesn’t occur and the tubes that hold the samples on the training boards are thoroughly washed between samples- a time consuming process. Currently, Elvis is working through two-to-three samples, in replicates, from each of the 17 possibly pregnant bears to ensure his predictions are consistent for the same individual. Each institution will be notified of the results for its bears within the week.
So while it might sound like a terrible job to us, we joke that Elvis is the envy of his peers at Iron Heart High Performance Working Dogs. While the other detection-dogs-in-training are smelling bed bugs, explosives, drugs, or toxic mold, Elvis gets to smell poop and is even rewarded for it- isn’t that every dog’s dream?
November 8, 2013 1 Comment
It has been years since the Cincinnati Zoo has had polar bear cubs born here, 24 years to be exact. Berit, our female, and Little One, our male, have been given every opportunity to “get the job done” on their own, but their mating has not produced a cub. So, we are increasing the couple’s chances by giving Berit two small hormone injections, 90 hours apart from each other, to induce a healthy ovulation.
The first injection was scheduled to be given, appropriately, on Valentine’s Day. Because the bears were never conditioned to allow hands-on medical care, the bear line ladies (Lisa Vollmer, Debbie Loebker, Lisa Potter, Tanya Dietz) and I spent the past three and a half weeks working diligently every day, twice a day, to get Berit ready. In that time we were able to train Berit to come to us on command and present her nose and shoulders. These behaviors would allow us to administer the hormone injections without needing to use anesthesia. (See my previous post about the training.)
Yesterday was “The Day” we had all been waiting for. And it worked!!! Berit was great. She came in like we asked, leaned in, and Veterinary Technician Amy Long was able to give her the first injection. She was a bit startled and left the training session, but it didn’t take her long to come back in. When she did, we gave her all of her favorite treats to reward her. We didn’t want the last thing she remembered to be negative so it was imperative that she came back into the training den and ended on a positive note.
We’re over the first hurdle, but we still have a long way to go. We continued the training this morning and Berit came into the training den right away. She seemed a little nervous to lean in but she did and it was an absolutely wonderful session! I am so excited for Monday now and am feeling very confident that we will be able to get both injections done on time. What a good girl she is!
Now it’s up to Little One to put on the moves and have a romantic Valentine’s Day weekend planned. I talked to the keepers about playing a little Barry White or Marvin Gaye to get them in the mood! Hopefully we will continue to live up to our title of the “Sexiest Zoo in America!”
February 15, 2013 5 Comments