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Category — CREW

How can you tell if a polar bear is pregnant?

Written by Crissi Lanier & Shasta Bray

It’s not as easy as one would think. Dr. Erin Curry with our Center for Conservation and Research of Endangered Wildlife (CREW) is committed to finding a way.

The Cincinnati Zoo is currently home to two polar bears, Little One and Berit. Little One is a 24-year-old male and, despite his name, is the taller of the two bears. Berit is a 16-year-old female. She has a longer and leader body and face and sharper features than Little One. Plus her ears tend to stick out a little more. Polar bears can reproduce until about 26 years old and Berit is at a prime age for reproduction.  She and Little One have been together since 2007 and are observed breeding every year, yet Berit has never had cubs. We aren’t giving up yet.

Berit and Little One (Photo: Crissi Lanier)

Berit and Little One (Photo: Crissi Lanier)

In the meantime, Dr. Erin Curry has been working very hard in the CREW lab to develop a non-invasive pregnancy test for polar bears. It’s important for zoos to know when their polar bears are pregnant to be able to properly care for and monitor them. It is very difficult to determine if a female polar bear is pregnant because there is a period of time between mating and implantation of about 4 to 7 months, making it extremely difficult to know if breeding successfully resulted in a pregnant female. Polar bears also go through a period called pseudo-pregnancy, in which females show an increase in progesterone level similar to that of a pregnant female, but in the end there is no cub born. Pseudo-pregnancy also occurs in otters, wolverines, red pandas and some cat species. These factors make it extremely difficult to determine if a bear is pregnant. While there is not a definitive test yet, she has multiple projects underway that look promising.

Maybe the answer can be found in feces. Feces samples are very easy to collect without requiring invasive procedures. Samples from about 55 bears from 24 different institutions across North America and Canada are sent to Dr. Curry three times a year, packed in dry ice, to research any possible chemicals that may be present in pregnant bears but absent in others. She is also examining various protein levels in the feces and has identified five proteins that are higher in pregnant bears than in non-pregnant or male bears.  More research is needed and it is a very expensive test. The goal would be to develop a cost-effective and user-friendly test.

Polar bear producing a fecal sample (Photo: SRSLYGUYS)

Polar bear producing a fecal sample (Photo: SRSLYGUYS)

You may have heard about Elvis, the polar bear poo-sniffing dog. Elvis has been pretty successful so far in distinguishing between feces from pregnant and non-pregnant bears. Dr. Curry continues to try to determine what exactly Elvis smells that alerts him to the pregnancy. Read more about Elvis’ story here.

Elvis the beagle sniffs polar bear fecal samples.

Elvis the beagle sniffs polar bear fecal samples.

Another way to determine if a bear is pregnant could be through an ultrasound, but conducting one on a polar bear has its challenges. Dr. Curry along with Megan-Kate Ferguson (Curator of Animal Development and Training) and the bear keepers have been working with Berit to desensitize her to being touched so she can undergo medical procedures, such as ultrasounds, without sedation. Desensitization is a process by which the animal is touched through a training wall with an instrument, such as an ultrasound probe, over a period of time as the animal becomes less reactive to it and it becomes like a routine practice. The animal is rewarded throughout the process, called operant conditioning, to associate positive rewards with being touched. As the animal becomes more used to being touched, more actions and commands are added to eventually complete the behavior necessary for the procedure. It is a multi-step process that takes time and patience to develop an animal’s level of trust and comfort. Megan-Kate explains this process further in previous blog posts here.

Now that Berit is conditioned to being touched through the training wall while standing with her abdomen pressed up against it, the next step is to perform exploratory ultrasounds to find her uterus. Even though we know Berit is not currently pregnant, the ability to even find the uterus at all is important if performing ultrasounds is to become a reliable way of detecting pregnancy. Despite a polar bear’s large size, the uterus is small and very difficult to find. Polar bears have two uterine horns, each of which (in a non-pregnant state) is roughly the size of a pencil.

Berit, the female polar bear (Photo: Crissi Lanier)

Berit, the female polar bear (Photo: Crissi Lanier)

First, Berit is called in to the training area and asked to stand up at the training wall. When she completes this, she is immediately rewarded with ground meat treats. Megan-Kate then hoses her lower abdomen down through the wall; performing an ultrasound is more successful on a wet bear because a more solid connection is made between the bear’s skin and the probe. There can’t be any air or space between the probe and the skin, which is difficult due to her thick, fur coat. Once Berit is sufficiently wet, Dr. Curry uses the probe to search for the uterus. A transducer on the probe emits sound waves into the body and picks up the echoes as they bounce back from organs. The ultrasound machine then translates the information into a two-dimensional image of the bear’s insides that Dr. Curry interprets. During this time, Berit receives treats and constant positive reinforcement as she stands very still and calm.

Dr. Curry prepares for the ultrasound procedure (Photo: Crissi Lanier)

Dr. Curry prepares for the ultrasound procedure (Photo: Crissi Lanier)

On this day, Berit cooperated like a champ and Dr. Curry was able to find the bowels, but not the uterus. Maybe next time!  Even so, it was a successful day of continued training with Berit.

Dr. Curry conducts the ultrasound on Berit (Photo: Crissi Lanier)

Dr. Curry conducts the ultrasound on Berit (Photo: Crissi Lanier)

Solving the problems facing polar bear reproduction in zoos isn’t going to happen overnight, but it’s an ongoing challenge that Dr. Curry and the rest of the Zoo are committed to seeing through. Learn more here.

September 1, 2014   2 Comments

Five Rhino Species Forever!

On Sunday, September 21, the Zoo will celebrate World Rhino Day. The Zoo is home to African black, Indian and Sumatran rhinos and is a leader in captive breeding and assisted reproductive techniques for rhino species here and abroad. We invite the Cincinnati community and our dedicated Zoo members to join us on World Rhino Day to celebrate our successes, learn about the challenges that rhinos face in the wild, and most importantly, partake in a fun-filled jam-packed day focused on the five species of rhino inhabiting our planet: African black, African white, Indian, Sumatran and Javan rhinos.

WRD Words

WRD LogoThe theme for World Rhino Day is “Five Rhino Species Forever”.  Stay tuned over the next month and a half as we countdown to World Rhino Day 2014 and blog about the special rhinos we have here at the Zoo and our efforts to conserve these magnificent animals and ensure there will be five rhino species forever!

August 7, 2014   No Comments

Another First for CREW: Indian Rhino Posthumously Fathers a Calf

CREW has done it again! We are excited to announce the birth of a female Indian rhino calf produced by artificial insemination (AI) conducted by CREW Reproductive Physiologist, Dr. Monica Stoops, and born on June 5 at the Buffalo Zoo. From a historical standpoint, this is the first offspring for a male rhino who never contributed to the genetics of the Indian rhino population during his lifetime – a major victory for endangered species around the world and a lifetime of work in the making.

Rhino calf Monica

Rhino calf Monica

The father, “Jimmy,” died at the Cincinnati Zoo in 2004.  Over the course of those ten years, Jimmy’s sperm was stored at -320°F in CREW’s CryoBioBank™ in Cincinnati, before it was taken to Buffalo, thawed and used in the AI.

Jimmy the Indian Rhino

Jimmy the Indian Rhino

“We are excited to share the news of Tashi’s calf with the world as it demonstrates how collaboration and teamwork among the Association of Zoos & Aquariums (AZA) organizations are making fundamental contributions to rhino conservation,” said Dr. Monica Stoops. “It is deeply heartening to know that the Cincinnati Zoo’s beloved male Indian rhino, Jimmy, will live on through this calf and we are proud that CREW’s CryoBioBank™ continues to contribute to this endangered species’ survival.”

“Tashi,” the Buffalo Zoo’s 17-year-old female has previously conceived and successfully given birth through natural breeding in both 2004 and 2008.  Unfortunately, her mate passed away and the Buffalo Zoo’s new male Indian rhino has not yet reached sexual maturity. Because long intervals between pregnancies in female rhinos can result in long-term infertility, keepers at the Buffalo Zoo knew it was critical to get Tashi pregnant again and reached out to Dr. Stoops for her expertise.

In February of 2013, Dr. Stoops worked closely with Buffalo Zoo’s rhino keeper Joe Hauser and veterinarian Dr. Kurt Volle to perform a standing sedation AI procedure on Tashi. Scientifically speaking, by producing offspring from non or under-represented individuals, CREW is helping to ensure a genetically healthy captive population of Indian rhinos exists in the future.  This is a science that could be necessary for thousands of species across the globe as habitat loss, poaching, and population fragmentation (among other reasons) threaten many with extinction.

The Buffalo Zoo staff monitored Tashi’s pregnancy over the 15-16 month gestation period and at 3:30 p.m., on June 5, she gave birth to a healthy female calf, weighing 144 pounds.

Rhino calf Monica,  Lead  Rhino Keeper Joe Hauser, CREW Reproductive Physiologist Dr. Monica Stoops

Rhino calf Monica, Lead Rhino Keeper Joe Hauser, and CREW Reproductive Physiologist Dr. Monica Stoops with CryoBioBank

“Without Dr. Stoops’ dedication to the species, and to the development of AI science, there is no doubt this calf would not be here today,” said Hauser. “She has spent countless hours spear-heading research and technology for Indian rhino conservation and the Buffalo Zoo is excited to acknowledge that dedication and announce that the name of the calf is “Monica.”

Tashi’s calf demonstrates that AI science is a repeatable and valuable tool to help manage the captive Indian rhino population. With only 59 Indian rhinos in captivity in North America and approximately 2,500 remaining in the wild, being able to successfully introduce genetics that are non or under-represented in the population is critical to maintaining the genetic diversity necessary to keep a population healthy and self-sustaining.

“We are always thrilled to welcome a new baby to the Buffalo Zoo, but this birth is particularly exciting because the science involved is critical to saving endangered animals,” said Dr. Donna Fernandes, President of the Buffalo Zoo. “This type of professional collaboration among AZA Zoos is vital to the important work we do as conservation organizations and we are honored to play a critical role.”

July 3, 2014   No Comments