polar bear cubs


Science for Kids: Observing

Do you remember watching panda Su Lin when she was born in 2005?

We are coming up on bear pregnancy-watch season at the San Diego Zoo! Both our giant panda Bai Yun and polar bear Chinook have bred this year, and we are anxiously awaiting signs that they are pregnant. Our fingers are crossed, and all the tools we use to monitor their status are just about ready to go. Of course, we are all excited by the prospect of bear cubs in 2012, and I think it’s safe to say that we will all enjoy the opportunity we have to look into the bears’ dens and observe these ursid moms and their cubs.

An important aspect of our conservation research is the study of animal behavior, which tells us much about the biology of the animals we love and provides us with tools to assess how the animals are doing and what a “typical” animal should be doing during important phases of its life. The study of animal behavior can provide tremendous insights into a species’ biology and gives us tools we can use to help conserve them. While the behavioral data we collect fits into a scientifically devised systematic framework, there is much to be gained from simple observation as well.

I have tried to share the joy of observing animals with my kids in hopes that it will also provide a connection with science and what it means to be a scientist. Often, when we are out and about in our neighborhood or at the park near our home, we stop to watch what the various animals we see are doing. It is amazing how exciting and exotic a squirrel can seem if you really stop and take a few minutes to watch the way it interacts with its environment, the way it responds to your presence, and the various ways it vocalizes and flags its tail to send signals to other animals around it. One of our other favorite animal-watching activities is going on a “bug safari,” which simply entails going into our backyard and turning over a rock. This simple excursion provides a window into the fascinating world of potato bugs, ants, and worms. Very cool!

Panda Cam viewers watched Mei Sheng grow to roly-poly cuteness in the birthing den in 2003.

Another readily accessible way for most kids to experience being an animal behaviorist is to watch our own exotic bears through Panda Cam and Polar Cam. While giant panda and polar bear cubs are undeniably cute, they are also fascinating to watch, and the care and patience the mother bear shows while tending to her offspring is fascinating. After each of Bai Yun’s cubs, our scientific and animal care staff watches the activity in the den in great detail and with unflagging fascination. I love that this very same view into the den will be available to anyone who visits our website.

We are all counting the days to the (hoped for) panda and polar bear births. As part of that, we are making sure that all of our camera systems and microphones are ready in the dens so that we can continue our studies of maternal care behavior in bears. This time around, I hope some young scientists out there will study the bears along with us.

Megan Owen is a conservation program manager for the San Diego Zoo Institute for Conservation Research. Read her previous post, Children and Nature.


Polar Bears: Breeding Season!

Kalluk and the rest of us eagerly await a polar bear cub or two!

We are all on pins and needles to see if the San Diego Zoo’s polar bears, Kalluk and Chinook, will breed this year. They have always been early birds by breeding in March and even as early as February! But normal breeding time for polar bears is April through May and sometimes as late as June, something we won’t even contemplate! From the looks of how flirtatious Chinook has been and how attentive Kalluk seems, our patience should be rewarded.

We are still participating in reproductive studies looking at hormones excreted in the bears’ urine and feces, but for the most part we still rely on behavior observations. One of the very interesting behaviors we see is with Chinook. Typically, a week before actual breeding and continuing right up to actual, we see her have seizure-like spasms followed by weakness in her back legs. The spasms last only seconds and the weakness only a few minutes. If you don’t know what these are, they can be very scary to see!

But there is no need to worry: Chinook is not alone with these. Most of the other breeding female polar bears show the same behavior. I have asked polar bear biologists who have spent many years observing bears in the Arctic and have sent them video of the process, and they are mystified as to its purpose. Perhaps it plays some role in preparing a female’s legs to hold the male during breeding, since males are usually twice the size, and she may bear his weight for long moments. In the last week we have seen Chinook have these spasms, and over the last few days they have increased both in frequency and intensity. This should be a sign that we are almost there!

We all know what follows: waiting to see if Chinook becomes pregnant and gives birth. I have been getting lots of experience working with polar bear cubs over the last few years since Kalluk and Tatqiq joined us as cubs in 2001. I have just returned from a second visit with Siku, the polar bear cub born at the Scandinavian Wildlife Park in Denmark. My first visit was to share what we learned in preparing our polar bear youngsters for life in San Diego. Siku still was not yet walking then and was not quite 13 weeks old. On my recent trip, Siku was now 21 weeks and was walking, running, swimming, and being overall an adorable monster!

Since Siku’s mom did not produce milk, the decision was made to hand raise him, which meant having close contact with him (not a problem when his fastest speed was a quick crawl!). He is now rambunctious and, as polar bears need to do, he is jumping, grabbing, and mouthing everything and everyone in sight. Mom polar bears are well equipped to handle this; human caregivers, not so much!

This trip was to help the team in Denmark move ahead with management that increases Siku’s independence and encourages his natural instincts as a polar bear. He did extremely well with every challenge of independence. You can imagine how difficult it is, though, for the team who has been caring for him all these months to see that maybe he didn’t need them as much anymore, or at least not in the same ways. I must say how proud I was to assure them and show them the close ties we have with our three polar bears and how much that strengthens when you’re not worried about when the next play jump comes from a now 60-pound and often wet white ball of teeth and claws! All meant in fun, but still dangerous for fragile humans!

Siku has lots of toys to encourage his natural learning behavior and is getting plenty of opportunities to learn with his training sessions. At 21 weeks, he has already learned several important behaviors from his keepers such as “sit,” “stand,” “down,” “shift,” “come,” and how to sit on a scale.

In choosing his name, thought was given to the chance to represent wild polar bears and the people who share the Arctic. Siku is from the Inuit language for sea ice. Siku will remind everyone that we are losing our arctic ice due to warming trends in our climate.  Science has proven this warming is caused by the increase of carbon emissions in our atmosphere. Siku and our three polar bears, Chinook, Kalluk, and Tatqiq, are ambassadors who remind all of us of their wild cousins and that we must make changes to help save their arctic home.

As you enjoy watching and hearing about these great ice bears, please keep in mind everything you can do to help. Then do it!

JoAnne Simerson is a senior keeper at the San Diego Zoo. Read her previous post, Polar Bears: Back to 3.

UPDATE: Two days after this was written, Kalluk and Chinook began breeding. November 2 is the first possible day of birth if Chinook is pregnant! The waiting begins. . .


Polar Bear Ultrasound

Will these two become parents this year?

Pieces of the Puzzle

Yes, we have begun the ultrasound exams with Chinook! Yes, she is cooperative, and we are very hopeful that this will be the year that once again we will have polar bear cubs at the San Diego Zoo. But how difficult is it to ultrasound a polar bear who is wide awake? The pieces of the puzzle are coming together.

The first puzzle piece, training, was relatively easy. Due to the great trusting relationship between Chinook and her keepers, and the history of learning together, teaching Chinook to roll over and hold went quickly. The next part was to get her to accept the ultrasound gel and actual probe on her belly. Chinook does very well with it all. And please keep in mind she is the only polar bear in the world who is trained for the ultrasound procedure.

We tend to take for granted the use of ultrasound to diagnose pregnancy. It is almost commonplace now. It wasn’t that long ago when ultrasound exams on our giant panda Bai Yun were also history in the making! Again one of the challenges is to find a very small fetus in a very big bear and ensure the safety of Chinook, the veterinarian, and, of course, the ultrasound probe! We are lucky to have many talented folks at the Zoo who have helped in designing and building various pieces of the puzzle. We now have a specially molded probe holder and removable bars on our training crate that allow for better movement of the ultrasound probe.

Every ultrasound image is recorded for review by our veterinary staff. We are confident that “when” (positive thinking) polar bear cubs begin to develop, we will be able to see them well and document another historical event: first-ever in utero polar bears!

Until then, we continue to collect urine and fecal samples to chart Chinook’s hormonal changes and monitor her behavior for dramatic and subtle changes that will alert us to her needs for a successful pregnancy and rearing of polar bear cubs. The cameras, microphones, and recorders are all ready, as long as she chooses those areas to den!

Now that we have all the pieces to the puzzle for our Chinook, it is important to remember that there are many pieces of polar bear reproduction that are missing. Much of our research with polar bear sensory ecology (see post Polar Bears: Getting Ready) will help shed light on pieces of the puzzle that would be very difficult, if not impossible, to do in the Arctic. To be able to document a polar bear pregnancy may give us more information on how to better protect polar bear maternity areas at critical times as more environmental impact jeopardizes the survival of our wild polar bears. How wonderful to be part of keeping polar bears in our future and not just a part of our history.

JoAnne Simerson is a senior keeper at the San Diego Zoo. Read her previous post, Polar Bears: Dare to Hope.

Update October 28, 2011: Both ultrasound and fecal hormone analysis look possible, but nothing is confirmed yet. Keep everything crossed!


Polar Bears: A Quiet Fall?

Only Chinook knows for sure...

Changes have begun at the San Diego Zoo’s Polar Bear Plunge. You may have noticed that Chinook has spent the last few weeks with Kalluk and Tatqiq for less periods of time. We have been watching her behavior and started to decrease her time with them as she began to show no interest in interacting with them and even began to push them away.

Female polar bears require great quiet, security, and seclusion when they den. Interestingly, it was Kalluk whom Chinook first began to let know he was not welcome too close. For the next few weeks, Chinook will most likely be out in our large exhibit only in the mornings for a few hours, and then she will spend the rest of her day in the off-exhibit management yard we call Polar Bear Park and the adjoining bedrooms while Kalluk and Tatqiq take residence for the rest of the day in the exhibit.

Chinook’s change in behavior is normal for a female polar bear that is pregnant. Her den is installed, and the bedrooms that will act as outer chambers to her den are cozy and quiet. Yes, we have the cameras installed so when the time is right we will be able to share any greatly hoped-for additions to our polar bear family with anyone viewing Polar Cam. Is Chinook pregnant? When will she give birth? We don’t have the exact answers to these questions, but we sure are hoping for good news this fall!

Here’s what we do know: in March of this year, Kalluk and Chinook engaged in what appeared to be very successful breeding behavior. Polar bear gestation is 195 to 265 days. Counting it out, we would expect to see cubs born between October 9 and December 15. The majority of polar bears cubs in the U.S. have been born in late November, but the earliest was October 11. You can see Chinook’s timeline is well within normal timing!

We have also been participating in a fecal hormone study done by the Cincinnati Zoo’s CREW (Center for Conservation and Research of Endangered Wildlife). The study is working to develop a test to be able to confirm pregnancy in polar bears and also be able to differentiate between actual pregnancy and false pregnancy. If the current numbers and protocols are correct, then Chinook’s hormones indicate that yes indeed she is pregnant! But at this point this is not a perfect measurement, so again we have a level of uncertainty that only seeing cubs will remove.

Luckily, Chinook is the only polar bear in the world currently that is trained for ultrasound procedures! We have regularly been doing these exams every week. We have yet to find anything but all the normal abdominal parts. It is very much like the first years with our giant pandas. . .so much to learn! How do you find a fetus the size of a peanut in a 200-plus-pound panda? Well, you can imagine the challenge when the bear is a 600-plus-pound polar bear! Suffice it to say that even if we don’t confirm pregnancy with ultrasound, it doesn’t mean Chinook is not pregnant. But how exciting it will be if we can confirm and have the first-ever images of a polar bear cub before birth!

Soon we expect Chinook will want only to be in the park and bedroom/den area. Kalluk and Tatqiq will spend their time in the exhibit keeping up their wonderful work as ambassadors. And I suspect we’ll all be crossing our fingers just a little bit harder! Patience . . . patience . . . patience. . .shhhhhh, it will be a quiet fall!

JoAnne Simerson is a senior keeper at the San Diego Zoo. Read her previous post, Polar Bears: Oh, Miss Chinook!

Note: JoAnne has provided some answers to questions posed in her previous post


Polar Bears: What Little We Know

Chinook: Is she or isn't she?

Chinook: Is she or isn't she?

We are anxiously awaiting the sounds of polar bear cubs squawking, humming, and crying in Chinook’s den. But we really have very little idea of when that sound will reach us because we still have much to learn when it comes to polar bear reproduction. Like other bears, the polar bear exhibits reproductive characteristics that are perfectly tailored to their environment. Without these adaptations, reproduction in the extreme, often harsh, climate of the Arctic, would not be possible.

Delayed implantation is just one of the adaptations polar bears have developed to cope with the challenges of life in the Arctic. This adaptation make predicting just when to expect newborn cubs quite a challenge.

Delayed implantation is a phenomenon common among all bears—at least we think! It serves its most obvious function in bear species that inhabit highly seasonal environments—that is to say, environments where food and good weather are not available year round. The more extreme the environment, the longer the delay: polar bears in the high Arctic are thought to delay implantation for about five months, whereas polar bears in more southerly latitudes may delay implantation by about three months. During this delay, regardless of how long it is, females go through an intensive feeding period during which they will gorge themselves on ringed and bearded seals for as long as possible before denning up in the fall. This summer feast allows them to deposit a thick layer of blubber that provides the essential nutritional support needed during the extended fast associated with pregnancy and denning.

True gestation takes about 60 days and typically begins in the fall, soon after pregnant females excavate and enter their subnivean (undersnow) dens. Females will remain in their dens until spring emergence, cubs in tow, ready to face the elements and begin the neverending search for food.

Fall will soon arrive in San Diego. Although it will be months before a chill wind is in the air, the change in day length (the first day of fall is that day when days begin to be shorter than nights) may cue hormonal and behavioral changes that prepare the polar bear for implantation, pregnancy, and impending motherhood. We are all watching Chinook with great anticipation: Is she or isn’t she? And when will she?

For a bear like Chinook, living at the San Diego Zoo where the weather is warm and food is always available, a layer of blubber is probably not necessary for successful reproduction. However, she has put on weight, and we are hoping that this is a sign that we will hear those hums and squawks from the den in the next couple of months. Stay tuned!

Megan Owen is a conservation program specialist at the San Diego Zoo. Read her previous post, Speaking of Polar Bears in Beijing.

Watch the bears daily on Polar Cam.


Polar Bears: Yesterday, Today, and Tomorrow

It’s hard to believe that it’s been 13 years since we opened Polar Bear Plunge at the San Diego Zoo in 1996! Chinook was 1½ years old, and Kalluk (pictured) and Tatqiq were still 5 years from existing. When we designed what would be at the time the world’s largest polar bear exhibit, we had not planned on how fast things would change in the polar bear’s world.

Polar bears were considered a “conservation dependent” species, and the greatest threat to them was overhunting. There were plenty of polar bears in zoos for folks to learn about, so many that the Association of Zoos and Aquariums (AZA) placed a moratorium on breeding, as there were no managed-care facilities left to house them. AZA’s population management plan aimed to keep the zoo population of polar bears healthy and in good numbers. In San Diego, we did not plan to breed polar bears and designed our facility to reflect that plan.

Today, everything has changed. Chinook is 14 years old, Kalluk and Tatqiq are 8 years old, and we potentially have cubs on the way! We are now adding a management yard onto the bedroom area and are about to embark on an incredible interpretive display that will be built at the beginning of 2010. These additions are very exciting and reflect the collaboration of several departments at the San Diego Zoo.

The decision to build the yard was brought on by the need to give Chinook and her potential cubs room to “grow” when they come out of the den. There will be a pool where the cubs will learn to swim, grass and dirt for Chinook to teach them the fine art of getting dirty, and lots of shelter for those all-important naps and lunch times!

The yard will also be great fun for Kalluk and Tatqiq when Chinook’s cubs are old enough to venture into the big exhibit and pool. Once Chinook goes into her den, our trio will be separated until Chinook weans her cubs and they go to their new home in another fabulous exhibit in North America. The construction is on a fast track: we need to get everything done and have the area quiet for when Chinook goes into her den, possibly as early as September!

Today, polar bears are now classified as a “threatened” species. We are all familiar with climate change and the melting of the Arctic Ice. We don’t know how many polar bears are in the wild, but we do know their survival is dependent upon the ice. In areas where we know the most about polar bears, we know that those populations are in dramatic decline. The San Diego Zoo formed a conservation partnership with Polar Bears International to raise awareness about the habitat of the polar bear. Along with scientists from around the world, we are identifying the greatest needs to help save polar bear habitat and then educating and inspiring our guests to make the changes needed.

In response to the declining polar bear population, AZA now has a Species Survival Plan for polar bears, a step not only to help continue to support polar bear populations in zoos but also in the wild. Tomorrow, we see the possibility of bears being born in San Diego, and the new yard will help us in the event we rescue polar bears. As the Arctic warms, more industry will move into the ranges where polar bears live and there will be more bear-human conflicts.

Just as we did when Chinook, Kalluk, and Tatqiq were orphaned, we are prepared to help. The new interpretive designs will give every guest that visits the polar bear exhibit a great feel for how we can make changes to help slow the warming of our planet and reduce our carbon footprint. We hope our fabulous polar bears will continue to inspire you to care about them and their wild cousins still surviving in the great icy Arctic.

JoAnne Simerson is a senior keeper at the San Diego Zoo.

Watch the bears daily on Polar Cam!


Polar Bear Answers

Chinook fishes for lettuce.

Chinook fishes for lettuce.

You have all done great with your ideas for reducing your carbon footprints! (See comments posted in Polar Bear Anniversary and The Polar Bear World.) And you’ve posed so many questions, I’ll try to answer some of them here.

First, let’s talk about polar bear fur. Polar bears are very clean bears! Even in the wild they use snow, kelp, and brush to clean their fur. Here in San Diego they do jump in the pools and then use the mulch to dry off. They also lick their paws and legs to clean them. Often you will see them rubbing their faces and rubbing against the sides of the pool for cleaning. Their fur is a bit coarse and long on the outer, or guard hair, layer. The fur underneath is soft and wooly.

Now let’s talk about some former residents of Polar Bear Plunge. Before Kalluk and Tatqiq moved to San Diego, we had another polar bear pair: Buzz and Neil. They were two males that lived with Chinook and Shikari from 1997 to 2001. In December 2001, Buzz and Neil moved to the Como Zoo in St. Paul, Minnesota. The Como Zoo is now in the process of building a new exhibit for “the boys,” so the two bears were moved to Detroit last April. The boys have been introduced to a young female, Talini, and have had great playtimes together, according to their keepers in Detroit. I did get the chance to visit with them when they first arrived in April, and they looked great! I have good contact with both the keepers in Detroit and St. Paul and always keep tabs!

What’s the story on our current residents? Born in Alaska, Kalluk and Tatqiq’s mother was shot by a hunter. She was wearing a satellite collar at the time, and the cubs were rescued within hours. You might like to know that most of the folks from the agencies responsible for their rescue have come by to visit the siblings and are always amazed at how fabulous and large they have become! We have been really lucky as well because we have formed great bonds with wildlife biologists from Alaska. We now all collaborate on so many projects to help the polar bear!

We have no reason to think that Kalluk and Tatqiq will not be able to live together for a long time. Although we consider polar bears to be loners, they do have a large repetoire of social behaviors and communications, and we have found that siblings in zoos do very well together.

Speaking of Kalluk, he has gotten a bit thinner due to the fact that he has not exactly had his mind on eating much lately. We’re not too concerned, as this is normal for males, and we know our boy can eat when he wants! We don’t know if polar bear cubs are in the immediate future, but Kalluk and Chinook have had some excellent breeding bouts and we are definitely planning on cubs! We are currently building a very small and cozy den inside our polar bear building in the hopes that Chinook may be pregnant. Female polar bears den in very tight quarters with just enough room for mom to turn around. The den is located in an area of the building where Chinook will be secluded from Kalluk and Tatqiq but will allow them plenty of space to come inside as well. Once Chinook shows us she wants that seclusion, we won’t have the three bears together until after the cubs are a few years old!

But before we have any parties we have a ways to go. Polar bears have delayed implantation, and we’re not sure what triggers the fertilized egg to implant or for it to be carried to a successful birth. Another puzzling aspect is that we suspect polar bears can have pseudo, or false, pregnancies. So Chinook may den up but we won’t know for sure until we hear or see cubs. The gestation is estimated to be 195 to 265 days. During the San Diego Zoo’s history of polar bears births, they all occurred from October 24 to December 7. That time frame would be a reasonable expectation. . .but we’ll be ready for any time!

JoAnne Simerson is a senior keeper at the San Diego Zoo.


Polar Bear Anniversary

Tatqiq and Kalluk, April 5, 2001

Tatqiq (on top of crate) and Kalluk, April 5, 2001

Eight years ago, on March 30, 2001, 22 pounds of polar bear arrived at the San Diego Zoo. The little male was 12 pounds and the little girl was 10. At this size it was difficult to tell them apart, so we shaved a spot on the head of the male. We affectionately called them “Bubba” and “Sissy.” They clung to each other in the strange new world, so we quickly reassured them with warm formula, soft bedding, and a quiet room.

What a cutie!

Tatqiq–What a cutie!

This was my first meeting with our now-famous brother and sister polar bears. Of course we found fitting names for them to replace the cute names they soon grew out of. We knew our boy, although tiny at the time, would grow, so when we found the Inupiaq word for thunder we chose “Kalluk.” And our little girl had the most perfect round, white face, so the Inupiaq word for moon was just right: “Tatqiq.”

What most folks don’t know is that these are actually their middle names! In choosing their names we wanted to do justice to the people that live in their land and also to the geography. Kalluk and Tatqiq were rescued on the pack ice in the southern Beaufort Sea along the north coast of Aalaska. The area was at the mouth of the Piasuk River. So, Kalluk is actually “Beaufort Kalluk,” our sea of thunder, and Tatqiq is actually Piasuk Tatqiq, river moon. We soon found that they were aptly named and Tatqiq had great depth to her name. Not only was she beautiful and peaceful; remember the Credence Clearwater Rival song, Bad Moon Rising? That’s how she quickly became Kalluk’s boss even as he soon grew to double her size. Would you believe he actually gained five pounds in one night?!



Seeing Kalluk with his bald patch on his head now brings back some very fun memories of the two tiny little orphans. Of course, his loss of hair now is due to the “love” bites and wrestlings with Chinook. It will all grow back when his new fur grows in with this year’s molt. Did you know that polar bears molt once every year? The old fur sheds off and is replaced with a brilliant, shiny new coat. We can use this fur loss to confirm maternity dens in the wild. When a female dens up, she will go through her molt. In the summer when the snow melts away, a pile of her fur will confirm where her den had been and where she had given birth to her new, tiny cubs.

I’ll say it for all of us: here’s hoping Kalluk and Chinook will be successful, and we’ll once again all enjoy a new generation of little polar bears!

JoAnne Simerson is a senior keeper at the San Diego Zoo.