Polar Bears

Polar Bears

38

What to Eat When There’s Nothing to Eat?

Bear ambassador Mi Ton Teiow finds relatively shallow snow, but no food, as the northern winter begins.

Bear ambassador Mi Ton Teiow finds relatively shallow snow, but no food, as the northern winter begins.

The answer? Nothing.

Most of us are familiar with the idea that some bears spend long periods of time in dens, inactive and not consuming significant amounts of food or water. Some bears in some locations survive eating nothing by doing almost nothing. They become inactive, which is sometimes called winter sleep or hibernation. Although you may be familiar with this aspect of bear ecology, have you thought about how incredible it is? These big mammals can go without eating or drinking for months, sometimes while birthing and nursing cubs, yet wake up without bedsores or weakened muscles! This is why the physiology of bears, including that of giant pandas and polar bears, has been a hot field of research.

The only way for a wild American black bear to survive for months without food in the northern U.S. is to save energy by hibernating in a safe, insulated den. The hole to the right of the tree trunk is the only obvious indication that there is an American black bear below the snow.

The only way for a wild American black bear to survive for months without food in the northern US is to save energy by hibernating in a safe, insulated den. The hole to the right of the tree trunk is the only obvious indication that there is an American black bear below the snow.

Although all female bears seclude themselves in dens to give birth to cubs, not all bears enter dens for long periods of time. There’s even variation within species in whether or not individual bears remain in dens or for how long. Researchers have found that in general, bears spend long periods in dens not to avoid cold temperatures, but to reduce their metabolic requirements when there is not enough food to survive environmental conditions. So, in the southern part of their range where their energy balance can remain positive, individual brown bears, Asiatic black bears, and American black bears may not den except to give birth. At last year’s meeting of the International Association for Bear Research and Management (see post, A Whimsical Bear Ambassador Arrives), Lorraine Scotson and Dave Garshelis reported that some sun bears might den for periods of time in the most northern parts of their range, meaning that non-reproductive denning may occur among at least half of the world’s bear species.

The holes melted in the snow are made by the black bear’s respiration.

The holes melted in the snow are made by the black bear’s respiration.

The giant panda is one bear species that has not been known to den in response to a relative lack of food, and perhaps it cannot do so. During the rare times when all the bamboo plants in an area have flowered and then died, the giant pandas have left the area in search of food; they have not entered dens. Perhaps this is because a bamboo die-off is unpredictable from the giant panda’s point of view, or perhaps this is because a giant panda eating bamboo cannot build up sufficient energy reserves to be able to wait out the lean time in a den, or maybe both factors play a role.

Adult polar bears also do not enter dens solely to avoid food shortages. Pregnant polar bears do spend prolonged periods of time in dens, but biologists think other adult polar bears don’t do so. However, polar bears in some populations regularly fast for extended periods when sea ice conditions don’t allow them to hunt. As for other bears, anything that causes a polar bear to expend more energy, whether inside or outside of a den, or to fast for a longer period of time, makes it less likely that the bear will survive. Climate change is doing just that by reducing the amount of sea ice available to polar bears: the bears expend more energy and go without eating for a longer period of time, creating a great challenge for the conservation of this species (see Polar Bears, Climate Change, and Mi Ton Teiow).

Hibernating bears often line their den with leaves, twigs, and grasses, insulating themselves from the cold ground and conserving additional energy.

Hibernating bears often line their den with leaves, twigs, and grasses, insulating themselves from the cold ground and conserving additional energy.

The Bear Specialist Group’s Ambassador Mi Ton Teiow recently made a visit to the northern US, where he found plenty of snow but little food for bears. After a short stay in this area, which receives an average of 45 inches of snow per year, the ambassador returned (fled?) back to sunny San Diego, where the last measurable snow fell on the city in 1967. The odds are good that Ambassador Mi will not be snow camping in San Diego any time soon.

Russ Van Horn is a scientist with the San Diego Zoo Institute for Conservation Research. Read his previous post, Courtship in Front of the Camera.

34

Spring in Air for Polar Bears

Kalluk digs a pile of snow.

Kalluk digs a pile of snow.

For those of us who live in San Diego, it nearly always feels like spring. (Sorry to those who are experiencing the polar vortex that hit a majority of the country recently!) Despite our consistent temperatures in San Diego, our polar bears follow seasonal changes similar to their wild counterparts in the Arctic.

We recently completed denning season, which normally occurs in the fall months (see Is Chinook Pregnant?). Now we are expecting to start a new cycle: breeding season! Those of you watching our Polar Cam may have noticed three bears on exhibit again. Chinook was reintroduced to Kalluk and Tatqiq after her months of requested seclusion. Chinook was showing some interesting behaviors associated with den making, but we eventually determined that she would not have cubs this time around.

The reintroduction went smoothly, and all the bears acted calmly. At first, Kalluk followed Chinook very closely while she walked around the exhibit. Then they both jumped into the pool for over an hour of play. Eventually, Kalluk was able to separate himself from Chinook, and all the bears rested in their favorite spots in Polar Bear Plunge.

Kalluk has been showing signs that he is getting ready for breeding season, such as an increased interest in sniffing Chinook’s footsteps and urine. However, Chinook is mainly acting coy and disinterested in Kalluk other than play (which certainly could be interpreted as slightly flirtatious behavior). Stay tuned as the saga continues…

Polar Bear Team

52

Polar Bears, Climate Change, and Mi (Ton Teiow)

Tatqiq's wild counterparts need more snow days.

Tatqiq’s wild counterparts need more snow days.

Mi Ton Teiow, the whimsical “bear” ambassador for the IUCN’s Bear Specialist Group (see post A Whimsical Bear Ambassador Arrives), has continued his travels, along with staff from the San Diego Zoo’s Institute for Conservation Research. With these travels, Mi is gaining experience in the multi-faceted world of bear conservation, which often includes extended periods of sitting and talking! While Mi might be anxious to get outside and do field research, our bear ambassador also understands that bringing people together to discuss the nuts and bolts of bear conservation is an important, and necessary, part of the process.

Recently, Mi traveled to the Toledo Zoo to sit in on the annual meeting of the Polar Bear Species Survival Plan (SSP). The role of the SSP (for polar bears or any other conservation-dependent species) is to bring together experts from zoos around the country to ensure that the members of the zoo community are being as effective as possible in supporting conservation efforts for the species. The focus of this SSP meeting was to enhance the synergy between zoo-based research, field-based research, and effective polar bear conservation. Speakers from the U.S. Geological Survey and researchers from the San Diego Zoo, Cincinnati Zoo, and Memphis Zoo presented overviews on current research and results, as well as ideas for the future.

Mi (center) and Megan (standing second from the right) pose with other members of the Polar Bear SSP.

Mi (center) and Megan (standing second from the right) pose with members of the Polar Bear SSP.

While listening in on discussions regarding conservation research, Mi also learned about the primary threat to polar bears: greenhouse gas emissions resulting from human activities have led to measurable and rapid changes in global climate patterns. The degree and character of these changes is not uniform, and different regions, ecosystems, and species are being impacted in different ways. When it comes to climate warming, scientists have documented the greatest degree of warming at the Earth’s polar regions.

This is bad news for the polar bear, because increases in both air and ocean temperatures in the Arctic have resulted in rapid losses of sea ice over the past several decades. Polar bears depend on the sea ice for their survival. Without the sea ice, polar bears cannot feed themselves or reproduce successful. This dependence on sea ice has left polar bears vulnerable to extinction in the face of climate change.

While the situation is critical for polar bears, it is not hopeless. Each and every one of us has the ability to help save polar bears by making small changes in our daily lives, such as turning off unneeded lights and riding our bikes more, to reduce our carbon footprint along the way. Because zoos have tremendous access to a large number and wide range of people, we play a critical role in polar bear conservation. As a conservation organization, we are responsible to get the word out, and we are happy that we were able to share our work with ambassador Mi Ton Teiow.

Megan Owen is an associate director for the San Diego Zoo Institute for Conservation Research.
Read about Ambassador Mi Ton Teiow’s previous adventure in Black Bears: A Conservation Success.

43

Is Chinook Pregnant?

Chinook, left, and Kalluk frolicked in the snow a few months ago.

Chinook, left, and Kalluk frolicked in the snow a few months ago.

Around this time of year for the past few years, the number one question we are asked by those familiar with our polar bears is “Is Chinook pregnant?” We nearly always answer with “We sure hope so, but….” Some of you may wonder why we are so elusive with our answer year after year. There are a number of reasons, none of them clandestine. Mainly, the polar bear community is still searching for all the answers. Things are complex in the polar bear world!

Did you know that polar bears have a wide range for gestation, spanning from 164 to 294 days in the wild (195 to 265 days in managed care)? If we determined possible birth on this information alone, this year Chinook could have given birth from July through September, based on when she bred with our male, Kalluk. However, we are aware of research that has studied historic data of births of wild bears and with other observations in the wild. It is hypothesized that date of breeding may not solely determine date of possible birth. Instead, it is a little more complicated than counting days from breeding time. Births generally occur between November and December, with the occasional birth outside those months even when breeding occurs in January, for example (when Kalluk and Chinook bred). Lastly, female polar bears have both induced ovulation and delayed implantation, which makes determining timing and the triggers involved difficult.

We are trying! Through research, we are continuing to learn more and more. Every other day, we collect urine samples from Chinook and fecal samples three times per week, all for hormone analysis. With Chinook’s full cooperation, we perform ultrasound exams weekly once her den is in place. (The den was set up this year at the end of September.) Through research and collaboration, we hope to gain new insights into the complexities of polar bear reproduction and give you more definitive answers in the future to the question, “Is Chinook pregnant?”

The Polar Bear Team, San Diego  Zoo

Watch the bears daily on Polar Cam.

493

Whimsical Bear Ambassador Arrives

Ambassador Mi travels the world in an effort to aid in the conservation of bears.

Ambassador Mi travels the world in an effort to aid in the conservation of bears.

There are eight bear species living today, and, until recently, the San Diego Zoo hosted ambassadors for five of them. We’re happy to announce the arrival at San Diego Zoo Global of another bear ambassador: Ambassador Mi Ton Teiow, also known as Traveling Bear. Ambassador Mi represents all eight living bear species as the special traveling ambassador of the International Union for the Conservation of Nature’s (IUCN) Bear Specialist Group (BSG). As such, Mi travels “to gain worldly experience and aid in bear conservation endeavors” and to promote the conservation of bears.

Ambassador Mi was “born” in the Lao People’s Democratic Republic and has since traveled to Canada, South Korea, India, Venezuela, and the US (Minnesota). Mi was officially posted to the San Diego Zoo Institute for Conservation Research (ICR) at the recent conference of the International Association for Bear Research and Management in Utah, and plans are underway for Mi to travel with our staff both internationally (China, India, and Peru) and within the US before traveling to Greece in October 2014. This bear gets around!

Although you may never have heard of the IUCN or the BSG, these are among the most credible international groups for the conservation of wildlife, and bears. The IUCN is the world’s oldest and largest global environmental organization, composed of more than 1,200 member organizations, including more than 200 governmental and 900 nongovernmental organizations. The BSG is one part of the IUCN, and it is made up entirely of more than 200 volunteer scientists from around the world. Several of our scientists are part of the BSG in various Expert Teams, including Ron Swaisgood (co-chair, Giant Panda Expert Team), Megan Owen (member, Captive Bear Expert Team), and Russ Van Horn (member, Andean Bear Expert Team). Many Institute staff members belong to other Specialist Groups within the IUCN (e.g., the Iguana Specialist Group, the Tapir Specialist Group), providing technical advice and mobilizing action for the IUCN as it works to “find pragmatic solutions to our most pressing environment and development challenges.”

Ambassador Mi Ton Teiow of the BSG was officially posted to the delegation from the San Diego Zoo Institute for Conservation Research on 17 September, 2013. From left to right: Megan Owen (ICR, BSG), Lorraine Scotson (BSG), the author, Ron Swaisgood (ICR, BSG), Barbara Durrant (ICR), Dave Garshelis (BSG), and Emre Can (BSG). Photo credit: Dr. Mei-hsiu Hwang, National Pingtung University of Science & Technology and the Taiwan Black Bear Conservation Association

Ambassador Mi Ton Teiow of the BSG was officially posted to the delegation from the San Diego Zoo Institute for Conservation Research on September 17, 2013. From left to right: Megan Owen (ICR, BSG), Lorraine Scotson (BSG), the author, Ron Swaisgood (ICR, BSG), Barbara Durrant (ICR), Dave Garshelis (BSG), and Emre Can (BSG).
Photo credit: Dr. Mei-hsiu Hwang, National Pingtung University of Science & Technology and the Taiwan Black Bear Conservation Association

Now, all of this probably sounds pretty bureaucratic, dry, and abstract, which might be part of why you can’t remember ever hearing of the BSG or the IUCN in spite of their conservation significance. However, given Mi’s colorful personality, willingness to put up with inconvenient travel without complaining, and hardiness in the face of harsh field conditions, we hope you’ll find Mi’s adventures to be enjoyable, memorable, and educational about bear conservation. Mi’s earlier travels have included a visit to the den of an American black bear, participation in technical scientific conferences, representing the BSG at the World Conservation Congress during a debate on curtailing bear farming, hiking to the highest point in South Korea, and waterskiing. Welcome to San Diego Zoo Global, Ambassador Mi Ton Teiow!

Russ Van Horn is a scientist with the San Diego Zoo Institute for Conservation Research. Read his previous post, Andean Bears and Their Favorite Food: Sapote.

145

Polar Bear IDs

Tatqiq wrestles with a snowball.

Tatqiq wrestles with a snowball.

Here are some hints on how to tell which of our beautiful polar bears you may be watching at any given time on Polar Cam:

Chinook: Everything about Chinook is round from every angle. Although the beauty mark under her left eye was removed (see post Polar Bears: Chinook and Her Beauty Mark), there is still a noticeable dark mark where her fur has not grown. When she sleeps, she is normally on her belly and rarely on her side. Chinook often sleeps just to the left of the waterfall, back by the double doors, on the beach at night, or in either mulch bed.

Kalluk: Obviously much larger than either female, Kalluk’s favorite rest spots are the middle rock shelter, back double doors, and the plunge point. So far, he is the only one who sleeps in the sandbox under the middle shelter.

Tatqiq: Long and lean with a nicely round belly, Tatqiq’s face is narrow and almost a mini-version of Kalluk’s face. Her favorite sleeping spot is the shelter by the beach. She normally sleeps on her side, but if she’s on her belly, she stretches her back legs out behind and rests her feet above her back. It looks uncomfortable, but Tatqiq loves it!

All three bears are capable of covering themselves in dirt, but Kalluk usually does just one side while both girls go for the total look. Happy polar bear watching!

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

UPDATE AUGUST 1, 2013:

SNOW DAY FOR POLAR BEARS! Help us raise the funds needed to provide our three bruins with a wonderful day of snow through our Animal Care Wish List. Offered in $10 increments, choose which bear you’d like to give “snowballs” to!

49

Polar Bear Night

Tatqiq loves that cold stuff!

Tatqiq loves that cold stuff!

Polar bears have very good eyesight both in light and dark. They spend half of the year in one or the other in the dramatic days of winter and summer in the Arctic. To survive, a polar bear must eat a seal at least every three to four days. When not hunting, polar bears are resting, perhaps as much as 20 hours a day. Polar bears are great bed makers, building nest-like beds in seaweed piled up on the coast, digging deep caves of snow into the bluffs, or resting in a shallow snow bed and letting the blowing snow cover them, making for a snug day den.

Chinook, Kalluk, and Tatqiq are no different from their wild cousins when it comes to bed making—they just have different materials. They love digging into the mulch or sand, Kalluk, especially, likes to sleep in his plastic kiddie pools. It is so fun to watch him organizing the pools so he can fit his entire 1,200 pounds (544 kilograms) into them! Tatqiq really likes the palm fronds and arranges them so they cradle her or she can hug them between her paws. Chinook’s favorite bedding is pine needles keepers rake up from the pines around Polar Bear Plunge. If pine needles aren’t available, she is a master with combining Bermuda hay and burlap bags for the most comfortable, cozy bed! One bed trait all three bears share is making a pillow. The pillow may be a log, a raised area of the exhibit, a cardboard box, or a shmooshed carrot bucket. You may see this on Polar Cam.

Do our polar bears sleep all night? Keepers suspect they do for the most part, although there is often evidence of carrot munching, playing, and exploring. Sometimes it is obvious there was activity overnight. Recently, new sod was put into the polar bear yard, and for two nights it was given the chance to take hold, with either Chinook or Tatqiq having access to the yard. On the third night, Kalluk shared it with Chinook. Keepers came in the next morning to find most of the sod in the yard had been tossed into the pool and torn into small pieces. Chinook was brilliantly clean, while a certain handsome boy, famous for his love of head wear, had mud and grass smears all over his head. Hmmmm, who played with the sod?

Do polar bears dream? Keepers get the awesome chance to be close to sleeping polar bears. Sometimes the bears’ lips or paws move, so it seems possible they are dreaming. They are certainly intelligent beings who show they are also creative in their play and approach to problem solving, so why not dream? We may never really know. There is so much still to learn about polar bears, and we continue to learn more each day with our fabulous trio.

We protect what we know and love. Chinook, Kalluk, and Tatqiq are very good at inspiring all of us to know and love polar bears. We all must find ways to protect the fragile habitat of the planet we all share. After all, could you even dream of a world without polar bears?

JoAnne Simerson is a senior keeper at the San Diego Zoo. Read her previous post, Polar Bear Mid-Day.

34

Polar Bear Mid-Day

Kalluk digs in during a snow day last February.

Kalluk digs in during a snow day last February.

Polar bears in the Arctic are tasting seal for the first time this season! Moms with new cubs, now five months old, are feasting on ringed seal pups. These pups are Mother Nature’s way of keeping the top predator in the Arctic well fed, especially polar bear families. Fifty percent of a ringed seal pup’s body weight is fat, a great boost to a mom that is providing meat and nursing growing cubs! After a good meal, mom will lie down and get some much-needed rest, and the cubs will curl up, entwined with her body.

At mid-day at the San Diego Zoo, the sound of a whistle means it’s time for the bears to come back inside. The bears know the whistle and also come when their names are called; yes, each bear knows his or her name! Chinook, Kalluk, and Tatqiq raise their heads from napping and move toward the open bedroom door. The bears are fed on a variable schedule: they may go off exhibit two or three times for another feeding, extra enrichment, or training sessions. This may happen anywhere from five minutes to several hours after their morning debut (see Polar Bear Morning). When the bears go back out, they may find new enrichment items, or keepers may toss treats (lettuce, melon, toys, etc.) to them from the overlook into the exhibit. This often spurs the bears to go swimming, and new toys really get them excited: they often pass up the food treat for the new toy!

The Arctic may have very warm days, even over 80 degrees Fahrenheit (26.6 degrees Celsius). Polar bears dig down into the permafrost to stay cool or lie in the shallow cold water of the coast in hopes of not overheating. Chinook, Kalluk, and Tatqiq do the same, except in the Polar Bear Plunge pool, of course! Chinook is the pro at sleeping with her head on the floating log and her legs floating out behind. Tatqiq prefers to sleep under the shade of the rock shelter. Kalluk usually cools off sitting on one of the rocks by the glass viewing area. We hose down the sand-bed areas every morning; this allows the bears to dig down into the damp, cool sand, just like wild bears digging into the cooling permafrost.

As often as keepers can, a presentation is done at the interactive wall by the beach area of the main exhibit. Typically these happen in the early afternoon. The bears enjoy this time so much that they often watch as the keepers head out and meet them there. The bears get to choose who does the “wall,” and sometimes both will participate. It is a great opportunity for guests to see, hear, and smell the bears. As keepers, we get to talk about how special our bears are, and guests get to experience being a few feet from a gorgeous, intelligent, powerful polar bear. What a thrill to have a bear look you in the eye only feet away! It’s a powerful connection. Guests walk away with knowledge of our three polar bears and perhaps feel connected to their wild cousins. They are also armed with knowing what we all need to do to help lower our greenhouse gases and protect the loss of more Arctic habitat.

At the sound of the whistle again, Chinook, Kalluk, and Tatqiq stop napping, soaking, swimming, or playing to come back into the building for the final time of the day. Since the morning, the keepers have been preparing bedding, overnight treats, and diets for the next day, and filling out the paperwork necessary to communicate to Zoo animal care staff how the bears are doing that day. Keepers have also discussed which bears will be in the main exhibit overnight and who will be in the polar bear yard, all with access to their indoor bedrooms, giving them the choice to sleep inside or outside. Kalluk usually prefers to sleep inside; both girls like to sleep outside. As Chinook approaches the time when she could give birth, she generally switches to sleeping inside. Once every bear has had dinner, each is given access to the assigned overnight areas. For the bears who go out to the main exhibit, they may have one more interaction with their keepers.

We protect what we know and love. Chinook, Kalluk, and Tatqiq are very good at inspiring all of us to know and love polar bears. Watch them daily on Polar Cam!

Coming soon: Polar Bear Night…

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

53

Polar Bear Morning

Chinook enjoyed some "snowfall" back in February.

Chinook enjoyed some “snowfall” back in February.

Polar bears in the Arctic spend their days hunting and sleeping after a good meal. For some, these meals need to last them during the upcoming months when the Arctic ice has melted, and they are forced to spend their days on land waiting for the fall cold to once again form the very important ice. For Chinook, Kalluk, and Tatqiq, their days at the San Diego Zoo typically begin at 6:20 a.m. when the keepers arrive at the polar bear bedroom building: breakfast time.

All the bears are brought into the building, whether from the main exhibit or polar yard, and go into separate bedrooms. Each bear has a set amount of food, based on nutritional need and calorie requirement, prepared and split into two or three pans. Breakfast is the bears’ favorite meal and their largest meal of the day! It includes a combination of meat, fat, fish, and dog chow. Kalluk has been known to eat 50 pounds (22.6 kilograms) of food in one day! In the Arctic, ringed seals are a polar bear’s primary food, but we don’t offer that here. Although fish is often added to zoo polar bear diets, it is done for nutritional reasons: polar bears don’t eat fish in the wild. After breakfast, the bears get a few carrots to keep those teeth clean and fill any tummy space left open.

In the Arctic, a polar bear’s diet consists of 90- to 95-percent fat. They are extremely efficient digesters of fat and can metabolize almost 95 percent of it to body fat. That process also provides great hydration, as the only water available in the wild Arctic is either frozen or salt. If our trio were to eat that much fat, they would be very uncomfortable in San Diego’s warmth. Instead, we reduce the fat in their diet to just 10 to 15 percent and have them fill up on food they get virtually no calories from such, as carrots.

While the bears are eating, keepers are cleaning the exhibit, changing enrichment items, and grooming the bedding. Chinook, Kalluk, and Tatqiq have the choice of two large mulch beds, the sandy beach and grass, the sandbox, and a variety of palm fronds or ginger branches. Our final morning task is to fill four to five buckets with carrots for our trio. The buckets allow the bears to take their carrots anywhere they choose to eat them; this is often onto one of their beds or even into the pool. Polar bears like to have choice and control in their lives, even if it means moving their carrot bucket 6 inches (15 centimeters) to the left and using it as a pillow when it is empty (I’m talking about you, Kalluk!).

At around 9 a.m., all three bears head out to the main exhibit. The keepers in the building then begin cleaning of bedrooms, which are typically filled with hay, burlap bags, torn-up cardboard, and plastic kiddie pools used for beds. Chinook, Kalluk, and Tatqiq are outside, representing their wild cousins and helping Zoo guests and Polar Cam viewers connect to the nature of the Arctic. We protect what we know and love. Chinook, Kalluk, and Tatqiq are very good at inspiring all of us to know and love polar bears. Watch them daily on Polar Cam!

Coming soon: Polar Bear Mid-Day

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

231

Polar Bears: Back to Normal

Tatqiq sniffs the air after a good roll in the mulch this morning.

Tatqiq sniffs the air after a good roll in the mulch this morning.

It’s been a whirlwind few months for all of us at the San Diego Zoo’s Polar Bear Plunge! It began on January 2 and is only just now settling into what we all refer to as normal! On January 2, we re-introduced Chinook to Kalluk and Tatqiq. It became very apparent in the previous week that Chinook was very interested in being with Kalluk. The three fabulous bears took up together as though they had not been apart for the months we were waiting to see if Chinook would give birth. All of us who work with our bears thought now we just wait for breeding season to start. The wait was NOT long!

On January 4, we came in to find it had begun and Kalluk and Chinook were inseparable. After a week of togetherness, it was all over for Chinook, but that was when Kalluk’s breeding drive took off. During the months that followed, we spent lots of time preparing foods that our boy would find appetizing to help keep any weight on him while nature takes over and he loses his appetite and seems to endlessly search for other mates. We also try different management techniques to see if any help to ease the road for Kalluk.

In the wild, male polar bears also go off their food in an effort to find receptive females. They, too, can lose an enormous amount of weight during this time, but adult males can make it up after breeding as they hunt yearlong on the ice and don’t have the need to fatten up to survive months in the den producing milk for cubs! However, with the summer ice beginning to disappear earlier, and knowing that males can be in breeding mode until June, it is worrisome to know what effects this could have on our wild male populations.

Polar bear breeding season can last into June, so although it is still possible that Chinook and Kalluk could breed again, Chinook’s behavior indicates that it is not likely. Kalluk is also showing fewer behaviors to indicate this as well. What does all this mean? We don’t have the exact answers, but it is likely that when the breeding occurred in January, Chinook ovulated, and if the egg was fertilized, she would not have the biological need to breed again. If this were in the wild, she would have begun hunting and storing as much body fat as possible to rear her cubs. It is interesting that so far this year she has been gaining weight more so than any year previously at this time.

The actual weight of polar bear cubs would not have a significant impact on their mother’s weight. Cubs are, after all, less than 2 pounds (1 kilogram) at birth. But we are optimistic that Chinook’s weight gain is an indicator that her body is holding on to every calorie she would need in the future for cub rearing.

Kalluk and Tatqiq have renewed their bond and can now be seen wrestling and playing together. Chinook is spending her days relaxing, eating carrots, and taking those beautiful, long soaks in the pool. She has quite a “full” figure these days; actually, she is gorgeous! So the warm San Diego summer will have her lounging and soaking most of the time. She will, of course, be given the option of staying in the air-conditioned bedrooms so you may not see her as much as in previous summers.

We know the question is already there: is she or isn’t she? We don’t know.  We will continue to work on research to give us better answers, continue to monitor Chinook’s behavior to provide for our girl exactly what she needs, and keep all fingers and toes crossed. We’re all getting pretty good at that!

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