We have finally started to see some behavior signaling that the hormones are having an effect. As of yesterday, she is starting to lose her appetite, has begun scent marking, and is interacting with water more frequently. Gao Gao has yet to respond to these changes in her, though he is keeping a close eye out. After his initial whirlwind days of excitement once the howdy gate was opened, he settled into a routine of checking the gate many times a day, sometimes calling to Bai Yun with soft bleats. With no response from her, Gao Gao would settle for a nap near the gate, often where he could see her while he rested. He’s being very patient, and soon that may pay off.

Bai Yun’s handlers have begun testing her for mating receptiveness using a very simple test. When our girl is brought into the back each morning to check her weight and get a urine sample (which she has been trained to offer on command), the keepers now use a slim piece of bamboo to perform a “tail-up test.” They use the bamboo to simulate the touch of a male who may be trying to mount, and apply pressure with it to the region of her lower back above the tail. When she closes in on her peak of estrus, such a touch will elicit a tail-up response, a flicking of the tail that seems to be a reflex in response to the touch. At her peak, the tail-up response becomes very strong, with her holding her tail high for several seconds, often backing up in the process. This type of behavior facilitates the mating process when the time is right. Thus far, Bai Yun’s response to the tail-up test is to sit down, which certainly wouldn’t help Gao Gao achieve the correct mating posture with her. Obviously, she is not yet at her peak!

I encourage everyone to come see Bai Yun in estrus over the next few days. It’s a fun time to watch the pandas, who usually are much more sedate, and it’s a rare occurrence around here since Bai Yun and Gao Gao have been so successful in producing cubs. If they succeed again this year, it will be at least two years before this happens again. This may even be the last solid estrus Bai Yun ever has, as the aged females have atypical, unpredictable cycles as they get older.

A word of note: once Bai Yun peaks and we are ready to pair the bears for mating encounters, we will close the exhibit. No visitors will be allowed in the queue during breeding attempts. This is largely because the queue is full of staff that is manipulating the enclosure gates from the queue, watching the bears to make on-the-spot decisions, and recording data. When mating is underway, we will open alternative areas of the panda facility for viewing Su Lin in her classroom exhibit.

Suzanne Hall is the senior research laboratory technician for the Giant Panda Conservation Unit of Applied Animal Ecology/CRES.

I recently described my difficulties with her attitude lately (see Kelly’s blog, A Stubborn Streak), so I admit I was a little nervous. I had already shifted her off exhibit once to clean and service. She readily perched atop her seat and I proceeded to give my talk and show the hand-feeding sessions I have been working her on. She did great, no problems. Now, I had to ask her to shift again so that I could place the enrichment on exhibit. She was flawless, not a bit of hesitation. I decided to try something non-obvious, so this day’s enrichment was a cardboard box filled with pine shavings and a few sprays of catnip. Before I released her back into the exhibit, I made a disclaimer so that the people wouldn’t be too disappointed.

Thankfully, my precaution was not needed. When she came out, she went right to the box and hopped inside. Rolling, rubbing, and those quirky little facial ticks of hers were the dominating behaviors for the next 30 minutes, that is, when she wasn’t playing hide and seek from her newly acquired fort. The guests smiled and cheered and helped to celebrate my personal victory. It’s a day like that one that makes dealing with her ‘stubborn streaks’ well worth it!

Kelly Murphy is a senior keeper at the San Diego Zoo.

The next All About Enrichment Weekend is May 12 and 13.

Murphy was very easy to train because he has the intelligence of domestic dog. He quickly learned to wear a carting harness and was introduced to the show stage the first week he arrived at Hunte. We had him in shows in less than two weeks, not only enjoying the work, but often stealing the show with his enthusiasm. Have you ever seen a pig dance? Well, Murphy runs out onto the stage and dances a little jig before the marveling crowd. We didn’t train it; he is just so happy to be there and shows it! If you’re happy and you know it, dance a jig!!!!

At first light in the morning, Murphy squeals to his trainers, letting them know he is ready to get started with the day, and that includes no delays in delivering his breakfast. What a pig! He has been gaining a mere 10 pounds (4.5 kilograms) a month since his arrival. His current weight is 90 pounds (41 kilograms), but will soon reach over 150 pounds (68 kilograms). Murphy’s favorite foods include carrots, yams, and turnips, but he also loves his herbivore pellets. Imagine gaining that kind of weight just from eating vegetables!

Stop by and see the show at Hunte Amphitheater soon. Murphy’s a real show hog!

Maureen O. Duryee is an animal trainer at the San Diego Zoo’s Hunte Amphitheater.

See video of three red river hog piglets at the Zoo.

Their first encounter through the door was an auspicious one. We are always concerned about the possibility of these two large bears getting aggressive with one another, and we are keen to avoid circumstances that could lead to injury in either animal. When Bai Yun approached the howdy gate cautiously and quietly, we watched with interest as Gao Gao approached from the other side. He bleated and chirped – a highly affiliative vocalization usually heard in females – as he came near. She sat and watched. He came closer and put his forepaws up on the gate, sniffing as he called to her. When Bai Yun decided she had had enough of this, she lunged at him, swatting his paws on the fence and barking loudly. This aggression didn’t surprise us, since Bai Yun is usually not so friendly to males until she is closing in on her estrus peak.

Gao Gao’s response was very encouraging. He chose not to escalate the encounter with Bai Yun. Instead, he put his paws down and sat quietly watching her from a few feet away. She did the same. After a minute, he ran away excitedly. He stood 20 feet away and watched as she turned and left the howdy gate. Once she was gone, he started up with his vocalizations again and returned to the gate, marking it repeatedly using a handstand posture, reaching up as high as he could go. It was as if he was letting her know that he understood she wasn’t ready yet, but he would hang around until she was. Good boy!

Over the weekend, these low-level interactions continued, and Gao Gao’s activity level has begun to climb. Though Bai Yun appears calm, relaxed, and sedate (short of peak estrus behavior, this is the next best thing for us to see), Gao Gao is a ball of energy. He’s been climbing and wandering his enclosures, all the while calling out his bleats and chirps. He has been seen body rubbing against Bai Yun’s resting places, transferring her scent to his fur. He is scent marking frequently, covering the howdy gate and climbing structures with his personal cologne. There is no question that Gao Gao is ready to go. How much of his behavior is related to changes in Bai Yun’s hormonal chemistry is still uncertain.

We continue to monitor Bai Yun for estrus indicators. This largely involves noninvasive techniques. Hormone assays are run using urine she deposits in tunnels or bedroom areas. Behavior is assessed by watching her move about on exhibit. Vulvar changes are assessed by looking at her as she lays on her back. The vaginal swabs are obtained when Bai Yun is brought into the tunnel and fed treats by her keepers, and the swabbing process takes mere moments. Usually she doesn’t even indicate to us that she notices the Q-tips as the samples are collected.

Some of you have wondered if Bai Yun might be getting too old to mate. Pandas have given birth as late as 18 years of age in China. Bai Yun may be older than the other U.S. panda females, but she has not yet senesced. She is nearing the end of her reproductive life, but whether or not she is AT the end of her reproductive life remains to be seen. There is no push for Bai Yun to have an estrus, but if she does, she will be given the opportunity to mate. This is still an endangered species, after all, and Gao Gao’s genes are special enough that the panda population would be well served to include more of his offspring.

Stay tuned to find out more as Bai Yun moves through her estrus. As the ball is rolling now, I will provide more frequent updates as I have them. If you are in San Diego and can make a visit to the San Diego Zoo this week, it could be well worth it to watch our boy Gao Gao strut his stuff in anticipation of the mating that may happen soon.

Suzanne Hall is the senior research laboratory technician for the Giant Panda Conservation Unit of Applied Animal Ecology/CRES.

Fear not. Bai Yun is, in fact, showing some other signs that she is nearing her fertile window. One measure of a female’s status is to note what changes her vulva undergo. We look for enlargement and dilation of the vulvar tissue and reddening of the skin in that area. These changes are driven by the changes in estrogen in Bai Yun’s body and are rated on a scale of 0 to 3. If we score a “0″, she is showing no change from her baseline appearance. If we score a “3”, watch out: it may be time to pair her with Gao Gao.

On April 11, we scored Bai Yun’s vulva as a “2” for enlargement and a “1” for color. This may seem somewhat unremarkable, except when compared to her last two fertile windows in 2003 and 2005. In each year, once we scored her as a “2” for enlargement, she mated with Gao Gao within six days. Are we that close to a breeding now? How can this be, if she is showing no signs behaviorally or with our primary means of monitoring estrogen?

There are potentially several factors at play here. As I mentioned in a previous post (Perplexing Pandas), Bai Yun is getting older now, nearing the end of her reproductive life. We have seen in Wolong that older females frequently have a truncated estrus, short windows in which they begin to show some behavioral signs of estrus and within days, not weeks, they progress to mating. There is some evidence that the vaginal cytology follows a similar pattern in these females. If this is the case with Bai Yun, we may be very close to her breeding window and we just don’t know it yet.

Another possibility is that because of her age, Bai Yun’s vulvar scoring may take a different path this year. Maybe she will remain at a swelling of “2” for a longer time this year than in years past. This remains to be seen.

In an effort to be ready for anything, and to ask Gao Gao for assitance in this matter, we will be opening the “howdy gate” between the bears during business hours from today forward. We may be “panda experts,” but Gao Gao IS a panda, and he is the best one to tell us if Bai Yun is getting near to breeding. All the estrogen monitoring in the world can’t beat our boy’s great nose! Bai Yun and Gao Gao will also rotate exhibits daily, to facilitate information exchange between them.

Stay tuned for further updates as estrus progresses. We’ll let you know what Gao Gao is telling us!

Suzanne Hall is the senior research laboratory technician for the Giant Panda Conservation Unit of Applied Animal Ecology/CRES.

Red kangaroos are the largest marsupials in the world. Females can get up to 4 feet tall and weigh 90 pounds; male red kangaroos can get up to 6 feet (1.8 meters) tall and weighing 200 pounds (90 kilograms). Jirra is known as a blue flyer, due to her outer gray coat color. Even though she is called a red kangaroo, only the under coat is red. Tangarie has a ruddy red coat and is often referred to as a red rover. Both animals are being trained to wear a harness and hop on a lead. Currently, you can often see Jirra in one of our shows.

Jirra was very easy to train once we found a food treat that she loved, which happened to be raw yams. Kangaroos are herbivores, eating a large variety of plants and vegetables. We slice the yam lengthwise to give her something to hold onto as she earnestly chomps on the vegetable. Jirra loves her show spot so much that sometimes it is hard to get her to exit the stage. Often the spokesperson needs to improvise with extraneous information while the trainer encourages Jirra to hop off stage. Kangaroos are the only large mammals to use hopping as a form of locomotion. This animal is capable of hopping at speeds of 30 miles per hour (48 kilometers per hour). We invite you all to watch her in action at the Hunte Amphitheater.

Maureen O Duryee is an animal trainer at the San Diego Zoo’s Hunte Amphitheater.

Meanwhile, in the off-exhibit areas, “the kids” (subadults Su Lin and Mei Sheng) are doing quite well. Su often sleeps in the Chinese elm tree, above the fence line but hard to see now that spring is here and the tree has its new leaves. Sheng tends to make a late-morning appearance as the keepers begin to prepare the bamboo for a later feeding, climbing into the still-bare poplar trees to the right of the Research Station, climbing as high as 50 feet to check out the behind-the-scenes activity. When Su Lin is in her tree, Sheng will often vocalize to her, and she may awaken and respond. (Notice the word “may.” They are living National Treasures of China, after all, and research subjects here. They are never forced to do anything!)

As spring progresses, we’ll try to keep you all up to date.

Ellie Rosenbaum is an educator and panda narrator at the San Diego Zoo.

Now we need a real trash can for recyclables. The new prop is taller than the old gray tub, almost as tall as Sven’s shoulder: he would need to hold the item higher and lean over the can to drop it in. Sven accepted and figured out the new prop within a few sessions (what a pro!), so I decided to try this behavior right before a show. I think I was more nervous than he was. We made the audience laugh when he missed and cheer when he hit the can, and they all understood the conservation message. More importantly, Mr. Sven Olof was having fun doing it!

I’m not sure if it is the height of the can or Sven’s intense desire to complete each drop, but his stare will linger long after the item has hit the bottom of the can, almost as if he wants to make sure it won’t bounce back out like the others did when they would hit the side of the tub. It is really funny, and I can’t take credit for this hesitation, but I will point out that this is the beauty of “capturing” a behavior, shaping a natural occurring behavior to occur more regularly.

Now I needed him to pick up more than one item before being reinforced, so I asked for the “recycle” after the first one and fed him on the second drop. This slowly increased to three pieces, then four, and so on. I really wanted this show spot to be his alone; I honestly didn’t think a trainer needed to be present, so I eventually trained him to accept my verbal commands from the back and faded myself off the stage.

Now you can see this conservation star do his thing all on his own. He runs out with his tail wagging and his head held high as he pops the trash into the recycling can, with the slight hesitation of making sure the stuff doesn’t magically pop back out after he has placed them ever so carefully. He doesn’t hog the show, but you might think he’s a ham!

Maureen O. Duryee is an animal trainer at the San Diego Zoo’s Hunte Amphitheater.

Sven can be seen recycling Sundays through Wednesdays.

Red river hogs are native to West Africa and live in a sounder, or group, of up to 15 individuals. Hogs eat both plant and animal matter and in the wild, their diet consists of grasses, plants, roots, fruit, and carrion. At the San Diego Zoo, we feed them a high-fiber pellet food along with carrots, yams, and some greens. Although the piglets are still nursing, we have already set up a door creep (a small opening just big enough for the piglets to enter) with a supplemental diet to aid in their eventual weaning. This piglet diet includes finely chopped vegetables, small grain, and milk pellets. They haven’t entered the creep yet, but it won’t be long until they find this food and take full advantage of mom and dad not having access to it.

Red river hogs are good swimmers and fast runners. At a week old, the piglets are out a few times a day while mom and dad eat but they don’t walk anywhere: they run! You have not seen cute until you have seen one of these piglets take off running at full steam from a dead stop. They leave little dust clouds behind them wherever they go. We can always tell if Tulia and her piglets have come out for a visit by the laughing and photo flashing of our guests!

When they aren’t running around, the piglets wrestle with each other by butting snouts. Males grow razor-sharp tusks and use these to defend their territories, and the piglets are learning to fight through play. Until they grow older though, the piglets’ defense when threatened is to crouch low and lay very still. Their striped pattern allows them to blend into vegetation very easily. When they grow into adults, they will turn reddish-brown with a white stripe down their backs and have white hair tassels hanging from their ears. Although red river hogs will flee when they can, if they are threatened they show considerable courage and both the stripe and tassels give the pig an image of being bigger.

For now, our little piglets are still striped and indubitably cute, with a short snout and fast feet. But they won’t stay this small for long. If you needed another reason to visit the Zoo soon, we have three good reasons to stop on by!

Nerissa Foland is a senior keeper at the San Diego Zoo.

Watch video of the piglets.