polar bear Chinook


Polar Bears: Getting Ready

Chinook enjoys snow day July 2011.

As you may already know, we are anxiously waiting to see if polar bear Chinook will have cubs this fall (see post Polar Bears: Dare to Hope). While we don’t have absolute confirmation yet that she is pregnant, her behavior and hormonal profiles look good, and we are hopeful. Of course, “hope” is just part of what we need right now: we also need to get ready!

For most of this year we have been monitoring and analyzing Chinook’s behavior and hormones, and these studies have provided great insight into her reproductive cycle. But our research effort really shifts into high gear during the postpartum period. If Chinook has cubs, we will be monitoring the behavior of mother and offspring and closely studying their acoustic communication. As part of a broader study of maternal-care patterns in polar bears (supported in part by Polar Bears International), every move that Chinook makes will be recorded on our den camera, and every squawk, moan, and hum emitted by her cubs will also be recorded, analyzed spectrographically, and correlated with both the cubs’ and Chinook’s behavior.

But what’s most important to the success of this research, and to the successful rearing and care of mother and cubs, is that all of our work is done without disturbing the bears. This requires thoughtful planning and making sure everything is in place BEFORE Chinook decides to go into her den to prepare for a birth. Every piece of equipment must be tested beforehand, because we can’t go back in and fix anything once Chinook has settled in. At this point, we are almost ready, and yes, we are very, very hopeful!

Megan Owen is a conservation program specialist at the San Diego Zoo Institute for Conservation Research. Read her previous post, Panda Su Lin: Cub.


Polar Bears: Dare to Hope

Chinook gives Kalluk's scruff a playful tug.

We’ve all experienced wanting something so bad that it hurts. People will tell you all kinds of things to make the waiting a bit less painful. You begin to fill your head with all the knowledge you can to know if it will really happen or not. And then comes the superstitions: don’t step on a crack, don’t talk about it, fingers and toes crossed. But no matter what, it just takes time to get the really special things that you want! What am I talking about? Wondering if polar bear Chinook is going to have cubs, of course! Is there anything else on our minds? Dare we hope?

As you know, Chinook and Kalluk marked Valentine’s Day 2011 by marking the start of the polar bear breeding season. If you were to ask Kalluk, he would tell you it was a successful season. The good news is that Chinook did not go back into season. This is very good, as we believe that when a female polar bear ovulates and there is fertilization, in most instances she will not cycle again that year. This is a good knowledge point.  Chinook, as many of you have observed, has also been putting on weight. This would not be due to carrying cubs, as they are barely over a pound at birth, but would make sense that her metabolism would compensate to hold as much as possible to nurse and provide for cubs—another good point of knowledge.

Polar bears experience delayed implantation, so we would expect to see Chinook changing behaviorally once the fertilized egg implants, around 60 days before birth. Yes, she is beginning to seclude herself away from Kalluk and Tatqiq. If gestation is 195 to 265 days for a polar bears, then from the 10 days of breeding, Chinook would be due between August 28 and November 16. Panic—it’s already September! Breathe, breathe. With such a long gestation, she could be implanting right now with a due date of early November.  Most polar bear births in North American zoos have occurred in the first week of November, the earliest was on October 13. Good things to know!

We have been collecting fecal samples for hormone analysis with the research branch of the Cincinnati Zoo and urine samples for hormone analysis with the Memphis Zoo. So far, nothing conclusive from the urine analyses, but the fecal analyses look positive for pregnancy. . .or pseudopregnancy. BUT—and yes, a big but—Chinook’s hormone profile is consistent with profiles of other polar bears that have given birth! Dare we hope?

So with knowledge in place, we’re avoiding walking under ladders, stepping on cracks, saying anything to jinx it, and above all, fingers and toes crossed. You better believe we are daring to hope that this time will be for sure!

JoAnne Simerson is a senior keeper at the San Diego Zoo. Read her previous post, Little Polar Bear: Lessons.


Polar Bear Hopes

High hopes for Chinook!

Chinook gave birth to two beautiful, fuzzy white cubs. Beep, beep, beep. . .I turned the alarm clock off. Yes, it was a dream, right? Or maybe a premonition? It seemed so real! As soon as I arrived at the polar bear building at the San Diego Zoo, Chinook came out of her bed to say good morning, so I asked her, “Are you really going to have two?” She simply winked at me; if she does know, she’s keeping us all in suspense. Every week during her ultrasound exams we are so hopeful of finding just a little hint of what may be to come. We realize what an incredible task this is to find something so small in such a large belly!

Chinook’s behavior is still very consistent with a pregnant polar bear. A few weeks ago we stopped letting her out on exhibit with Kalluk and Tatqiq, since she seemed to be less tolerant of their presence. This week we stopped having Chinook on exhibit at all or letting Kalluk and Tatqiq into Chinook’s side of the bedroom area and yard. We will continue this for the next few months until we know for sure if our Chinook will be joined by one or two little ones. We are now in the expected due date range if Chinook is pregnant: October 9 to December 15. Believe me, we are all so hopeful and excited!

Our other two polar bears, Kalluk and Tatqiq, are having a great time being full-time ambassadors. With autumn arriving, it seems they spend more time in the pool. Every day the brother-and-sister pair are enjoying roughhousing together. They are great playmates and always play to each other’s level, never getting too rough. It is so nice to see that their bond has stayed so strong.

This week they welcomed keeper Hali O’Connor back from her great adventure up north at Keeper Leadership Camp, sponsored by Polar Bears International, in Churchill, Manitoba, Canada. (see Hali’s most recent post, More Arctic Ambassador Adventures) and met this year’s student ambassador, Rachel. She will be up in Churchill this week learning all about polar bears and what we need to do to help slow the process of our warming planet, and, in turn, prevent the complete loss of polar bear habitat. (See Rachel’s post, Countdown to the Arctic.)

Being an Arctic ambassador sometimes seems a daunting task: how to inspire behavior change when it often feels so doom and gloom? It is a global issue and must start with individuals. We’ve faced other environmental problems and won. Remember the hole in the ozone? As individuals, we worked to find the cause, develop solutions, and act as a global community. The unprecedented international action to the hole in the ozone, which was first seen 25 years ago, has paid off. Scientists are now predicting a rebound and that by 2080 the global ozone will return to 1950s’ levels. We now all need to return to action to have the same impact to slow, stop, and reverse the rate of our planet’s warming. After all, we want Chinook’s cubs to know we are doing everything we can to save the Arctic for their wild cousins so they, too, will be Arctic Ambassadors.

JoAnne Simerson is a senior keeper at the San Diego Zoo. Read her previous post, Polar Bears: A Quiet Fall?


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: Who is Who?


Having a tough time telling “who’s who” on the camera? Here are a few helpful identifiers:

First, now that breeding season is over, if you see two bears together most likely it is our siblings Kalluk and Tatqiq. They truly enjoy each other for playing and often times sleep in close proximity, especially on our beach! Chinook, it seems, is not joining the two this year for the summer frolic season. Instead, she is content with watching them and resting by a favorite pile of carrots. She also loves to sleep to the right side of the waterfall or out on the point.

We maintain a variable schedule of which bear is on exhibit when, but for the most part, Kalluk and Tatqiq are on exhibit more often in the evenings, and Chinook is in the bedrooms and polar bear park. This is intentional because she does seem to enjoy this area, and if she is pregnant, this will be where she will live for up to six months and introduce her cubs to the great world of grass, dirt, and swimming!

Individually, Chinook is the most round of our three. Her arms look very solid, as does every part of her. When polar bears put on weight, it first goes on their belly, then their bum, then distributes over the rest of their body. The bear you see with thick arms, neck and legs, rounder profile, and in the close-up has a beauty mark under her left eye, is Chinook! Again, her weight gain is intentional in preparation that she will be denning up this fall. We want to be sure she has plenty of energy to support any time she might spend fasting during the denning period. Female polar bears in the Arctic regularly go without food for four months while in their dens; due to the loss of sea ice, this time in now increasing to as much as nine months. This is why we are seeing smaller litters and an increase in the mortality of cubs in the wild.

Kalluk and Tatqiq are almost mirror images of each other except, of course, that Kalluk is twice the size of Tatqiq! They both have more slender appearances and are very tall looking. Actually, we suspect Kalluk may well be the tallest male polar bear in any zoo. We measured him standing up, and he is over 10 feet (3 meters) tall! Kalluk is the “basketball player”; he throws everything and has definitely learned where he can throw toys and have them come back to him. Tatqiq tends to wrestle with toys. When you see two bears wrestling, Tatqiq stands fully up but Kalluk only half way; this is so he and Tatqiq are the same height. Also, don’t worry if you see them dragging each other around by their head or ears; they’ve done this game since they were six-month-old cubs!

As we all enjoy our summer weather, I hope we are all still thinking about conserving energy. Have you raised the temperature on your thermostat for less air conditioner use? Evening walks are a great, cool time to get to know your neighborhood and turn off the computer and TV! We are now seeing the lowest recorded ice amount in the Arctic for the month of June. The rate of melting sea ice is at a historic record. Let’s do a bit more to slow this rate of warming. Check out our Polar Bear Plunge Web site for more ideas!

JoAnne Simerson is a senior keeper at the San Diego Zoo. Read her previous post, Polar Bears: A New Look.


Polar Bears: Crash, Slurp, and Shadow

Kalluk, left, and Chinook

Could it be we are nearing the end of our fantastic remodel of the Conrad Prebys Polar Bear Plunge at the San Diego Zoo? Anyone who has remodeled their home knows the joys and dilemmas that improvement brings. Most of the work that impacted our bears was completed last fall with the building of our management yard and the experience wall.

The bears love the wall area, and with all the great rain we’ve had, the yard is thick with green grass. In fact, we’ve begun calling the yard Polar Bear Park! We did, however, want to do some remodeling in the exhibit: remove some of the deadwood to make viewing easier. We set about renting a huge crane to come and lift the wood out and move the huge root balls, but…

The project started when we brought all three bears in for the afternoon and night while we cut through all the metal thread that held everything together, cut the wood into smaller, more manageable pieces, and basically prepared all for fast work the next morning. Everything needed to be done by 9 a.m. so the crane would not block the road.

We were all in an hour early; we made sure the bears were all fed and happy with new beds or enrichment and then set up for the crane. The crane arrived early but, OH NO! The hydraulic line broke! The crane was out of commission. Now what? We can’t let the bears on exhibit—it was too dangerous with all the loose logs. In steps teamwork!

One of our animal care managers got a bobcat tractor while ropes, chains, pry bars, and determination were gathered. For the next two hours logs were pulled off and out with loud crashes and moved into better positions. The polar bears’ “living room” took on a whole new look. By 9 a.m. we had everything done and secure so our trio could come out and assess our work. We expected lots of curiosity from them, but they took a look, a sniff, and went off to their carrot piles! We will be doing a bit more work before the grand re-opening on March 26, including removing one more root ball and filling part of the center shelter area with sand for another sleeping area.

There is also a return of that wonderful “sllluuurrrrrrpppppp” sound every day from Kalluk. What does this mean? As we are beginning to understand, scent is an integral part of polar bear communication. Just as breeding season begins, Kalluk busies himself with smelling everywhere Chinook has stepped. He flattens his nose and mouth to the floor and slurp-inhales with all he’s got to assess where Chinook may be in her approach to breeding season. We now are seeing him less and less away from her as he has become her shadow. This year, he seems to be less anxious about it, perhaps after last year he has gained some maturity and confidence. In the past few days we have begun to see Chinook become more flirtatious with him, and she often adds a nice face rub to her greetings to him. She rarely goes anywhere now without her 1,000-pound shadow!

Tatqiq is beginning to be an outcast, but she also seems to have gained some confidence. She is not backing down from Chinook but instead stands in place and offers behaviors that neutralize Chinook’s advances. Every day we do offer all our bears the opportunity to show us what they need, and so far everyone still wants to be together. We are really happy that when it comes time to give someone a break, they get to spend it in the new Polar Bear Park!

When you come to visit after re-opening on March 26, you will be able to see through the exhibit and look on the hill and see our bears in their lush, green park.

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

Watch video of the new statues and interactive elements being moved into place at Polar Bear Plunge.


Polar Bear Tatqiq: Arctic Ambassador!

Tatqiq investigates the new management yard at Polar Bear Plunge.

Tatqiq investigates the new management yard at Polar Bear Plunge.

As fall has come, so has quiet to the Conrad Prebys Polar Bear Plunge. The management yard is being well used by Chinook. She certainly has her routine down: greet Tatqiq and Kalluk over the moat, find treats, eat treats, dip in pool, roll in dirt, completely cover entire body except for the white fur around eyes, go inside and see what my keeper is up to. Oh, too bad the nice clean bedrooms are now covered with muddy paw prints! Chinook really has perfected the art of the dirt roll! Still no confirmation of pregnancy, but also no behavioral change to indicate she is not pregnant. Our fingers are still tightly crossed.

Many of you have noticed the new wall by the beach. This is the new “Guest Experience Wall” that will be unveiled next year when the new interpretive area opens. However, Tatqiq has ignored all memos saying that this will happen next year. She has installed herself as the overseer of all guest greetings and is chief model for all polar bear close-up photography. In brief, she is THE Arctic Ambassador, and she is holding court every day as though she is the queen of the beach, no longer the princess! What an incredible opportunity now to have only three inches of glass separate you from a polar bear so willing to pose for your photos! More surprises are ahead when we do officially open the wall in March.

Kalluk has also enjoyed having the entire beach area back. Every night he chooses between sleeping on what is left of his kiddie pool or building a soft, cozy sand bed. He does seem to enjoy watching the show Tatqiq puts on with the guests and will join from time to time. He also spends time watching Chinook next door in the yard. I’m not sure what he is thinking. Perhaps he, too, is wondering if cubs are on the way. If not, we expect to begin seeing changes in him by the end of December as his hormones prepare him for the next breeding season.

For me, I am in Canada, working with our conservation partner, Polar Bears International, and spending time with the polar bears of Churchill, Manitoba. This will be my ninth fall with our incredible furry ice bears. Even in such a short time I have seen great changes in the polar bears due to the change in ice. Please take the time to read our student Arctic Ambassador Daniel Straub’s impressions of his time with the bears (see post Northern Lights Perfect Backdrop for Polar Bears) and the great information shared by Dr. Ron Swaisgood of his first adventure to Churchill (see post Hope for Polar Bears). With how fast the Arctic is changing, anyone lucky enough to experience this disappearing land of ice must be an ambassador to inspire others, who can’t come north, to care enough to make the changes to save this beautiful habitat and the animals and people who live here. Tatqiq is a great model as an Arctic Ambassador; she’d love to share the role with you!

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


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: Quiet, Please

polar_chinook_walkingThe Conrad Prebys Polar Bear Plunge at the San Diego Zoo has been a really noisy place during the past few weeks. Yes, lots of construction, but mostly the noise is coming from the questioning. . . is she? We’re talking about the hoped-for pregnancy of Chinook! We still don’t know. ..for sure. That said, Chinook has gained over 20 percent of her normal body weight and has now slipped into the most calm, contented, beautiful mood we have ever seen in her 14, now almost 15, years. The most activity she shows is munching on her carrots while glancing over at the silly antics of Kalluk and Tatqiq and slowly dipping into the plunge pool to luxuriate and soak.

All this is very normal behavior for a pregnant polar bear. What we don’t know is if she could be experiencing a pseudo (or false) pregnancy. At this point, the only way we know to tell the difference is when we see the cubs. And before you wonder….Yes, we are beginning to perform ultrasound checks on Chinook. We really don’t know what to expect or when we might see something. It’s very reminiscent of the first time we performed ultrasound on our giant panda Bai Yun! The big difference is we’ll be looking for a fetus about the same size as a panda baby in a body currently at 650 pounds (295 kilograms)!

The preparations for the den and adjacent bedrooms are almost complete. The den is ready for installation as soon as Chinook gives the word; the bedrooms adjoining the den are closed in, darkened, and have sound protection; and yes, the camera mount for the den is ready! We don’t yet know if we’ll be able to have a live camera feed, but we’re working on that.

The polar bear management yard will be completed within the next few weeks. This yard will be the first place Chinook will take her cubs outside. The pool is designed specifically for cubs learning to swim. And, most importantly, the yard is all natural dirt. Can you imagine the pigpen lessons Chinook will give her cubs? Oh, the art of how to get really, really dirty!

Keep an eye on things, and when you see us put a hush over the area and ask, “Can we have quiet, please?”, you’ll know we are getting closer to knowing “Is she or isn’t she?”!

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

Watch the bear daily on Polar Cam


Sugar Bears!

Long ago my dad would take me early in the morning to the donut shop to get the freshest donuts. I remember how beautiful the donuts were when right out of the fryer the baker rolled them in granulated sugar and they just sparkled in the lights of the donut shop! Last Tuesday, May 12, we put over 100 bags of playground sand on the beach for the San Diego Zoo’s polar bears. And by Tuesday afternoon I had three beautiful “sugar donuts” sleeping on exhibit!

The bears were so excited to see and smell the sand. So after quick swims they rolled themselves in the beautiful white crystals. Both Chinook and Tatqiq kept their black noses clean, but our boy Kalluk had a sparkling nose! I think I love these “sugar donuts” even better!



So many of you have commented on the beautiful white bear you see on the Polar Cam. Are you ready for this? That is our “pigpen” Chinook! She has never looked so beautiful! She has completely finished her molt and seems to be glowing! She was very happy the other day, as well, when the new essential oils from our enrichment wish list came in. Once again she anointed herself with her favorite, “Roman chamomile.” Still no answers on if we’ll see cubs this fall, but we are getting ready. Then den is almost complete and we’re still working out the configuration to hopefully have a den camera that can be shown on the Zoo’s Web site.

Kalluk is definitely out of his breeding daze. I’m sure you’ve seen how much more time he now spends playing and swimming. Tatqiq is ecstatic to have her play buddy back! We are still keeping a variable schedule on all three bears. You may see any combination of one, two, or three out!

I see many of you are asking about what the bears like for beds. On exhibit we have the fresh sand, mulch piles, and burlap coffee bags (which they love). Palm fronds are always a big hit whenever we can get them. In their bedrooms, we can use other items without worrying about clogging up the filtration. The bears do love Bermuda hay, pine needles, mulch, rubber stall mats, and cardboard boxes! All three of them are very good at making their beds using whatever we give them. But Kalluk does seem to take great care in his creations, spending much time moving things around so they are just right. He also uses many of the toys as pillows. It’s pretty funny watching a 1,000-pound boy being so particular about his bed!

In the Arctic, polar bears make beds as well. If the snow is deep enough, they’ll break through the icy crust and dig down to get shelter from the wind. They also dig into kelp beds along the coast. It’s a great soft bed that’s good to eat as well! A few years ago, a big male bear broke into the cardboard bin at the town recycle center in Canada and made himself a bed. He apparently was in there for several days before anyone noticed. Keep recycling. . .it’s good for polar bears in many ways!

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