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marsupials

4

Visit the Mob

Tinka the parma wallaby graduated from nursery care on February 1, 2012 (see Wallaby Tinka Hops Away). Her introduction to the parma wallaby mob of five adult females has been a resounding success!

Now the mob has taken up residence in an exhibit across from the Zoo’s new 4-D theatre, between Elephant Odyssey and the west end of our popular Skyfari aerial tram. Senior Keeper Elisa Evans says that Tinka is the first wallaby to greet her on the morning check. She is still friendly and super sweet. Although Tinka has grown a lot, you can still pick her out of the crowd, or mob, as a group of marsupials is called. Tinka’s fuzzy coat is grayer in color, and she is still a bit smaller than the rest of the girls.

Please stop by and visit Tinka. She will be just one of the gang, as it should be, sunbathing, feeding, or simply hopping around in the tall grass. We are so proud of her!

Janet Hawes is a lead keeper at the San Diego Zoo.

10

Wallaby Baby Catches Up

Tinka peeks out of her larger pouch.

Be sure to read Janet’s previous post, Wallaby Baby: New Coat, New Adventures.

We knew that Tinka, a parma wallaby, was small for her age since her arrival in the San Diego Zoo’s Neonatal Assisted Care Unit. All along, one of our main focuses was to encourage her to eat and gain weight. We surmised that since her mom had been so ill, either the quantity or quality (or both) of Mom’s milk wasn’t enough for the baby to attain a normal size. We weighed Tinka every morning before her first bottle, and we found that she gained weight nearly every day. Though her weight climbed, it was never enough to compensate, and she remained 30 to 50 percent of normal size range. The statistics we had on normal baby parma growth ended at around 200 days. Now we were in uncharted territory, unable to determine exactly how Tinka was doing.

We noticed that Tinka’s muscular tail and legs were looking more substantial. She developed an endearing little pad of fat under her chin, characteristic of the species. We decided to check with some other zoos to see if there was any weight data available on joeys Tinka’s age. Cooperation between zoos in sharing information like this is vital. There aren’t many zoos that have an organized hand-rearing program. Fewer have experience with marsupials, and even fewer still have had experience with parma wallabies. We were lucky to find that the Cleveland Zoo had raised a parma wallaby recently, had kept excellent records, and were willing to share them with us.

Tinka and Janet enjoy some play time in the nursery.

When we compared Tinka’s weight to the animal from Cleveland, we were surprised with what we found: our little girl was now 80 percent normal size! Tinka had been experiencing what is known as compensatory growth, which occurs when a small animal “catches up” to normal weight. We were delighted with this finding.

By now, Tinka was consuming solids well, jumping out of her pouch as soon as a fresh food pan was placed in her enclosure. Her favorite food was freshly chopped greens. She had become so wide (especially across the backside) that she was having trouble wiggling into her small pouch. Her fore end made it through the opening easily, but the back end was a struggle! We provided her with a larger, roomier model made from the same design. Tinka, our once-fragile neonate was now a healthy parma youngster. It was time for her to graduate from the nursery.

Tinka hops out of her nursery bedroom.

One of the most common questions I am asked as a nursery keeper is, “Don’t you miss them when they are gone? Aren’t you sad when they leave the nursery?” My answer is always the same. When an animal is ready to move on, it means that we have fulfilled our role. The aim from the start was not to make the animal into our pet, and the focus was never about the relationship between the animal and the keeper. Instead, the focus is on graduating a healthy, well-adjusted animal that will go on to lead a productive life. It is impossible not to look back on rearing an animal without some sense of letting go. But that was the plan all along, and now it was Tinka’s time.

The koala keepers prepared a nice temporary space for Tinka in an off-exhibit area. We outfitted it with some logs and hay and hung a heater above one of her pouches. Though she was used to visiting with the adults and spending time in a pen by herself every day, she returned to the nursery for overnight stays. On December 26, Tinka left the nursery for the last time. That evening, nursery keepers went out to visit Tinka in the early evening to check on her, and she seemed fine. Tinka was settled and stress free the following morning, having spent a comfortable night tucked in her heated pouch.
Tinka continues her socialization. A gentle adult female was selected to serve as a companion, and Tinka spends her days in a warm and sunny pen behind the Zoo’s parma wallaby enclosure. Soon, Tinka will be introduced to all the “girls” in the group. We have decreased her feedings to just one abbreviated bottle in the morning, and her weight continues to climb.

Janet Hawes is a senior keeper at the San Diego Zoo.

5

Parma Wallaby Baby: Life in the Pouch

Tinka peeks out of her surrogate pouch at six months of age.

Read Janet’s previous post, A Pocketful of Fun: Parma Wallaby Baby.

We use developmental markers rather than birth dates to determine gestational age in marsupials.  Some of these markers include eyes open or closed; ears pinned or erect; and the presence, location, and amount of body fur. When she arrived in the San Diego Zoo’s Neonatal Assisted Care Unit, Tinka’s eyes were opened, but her ears were still pinned to her head, and she had thin, pink skin with no body fur whatsoever. These markers told us that Tinka was very young and vulnerable. We were careful not to be too confident about her survival.

Janet attends to Tinka in her pouch.

We were grateful to gain the valuable experience of caring for a marsupial this young and unformed. In those first few weeks, we said each day “I can’t believe she is still with us!” Tinka gained weight very slowly and slept soundly in her pouch between feedings. We kept things in the back room where she was housed very quiet and peaceful for her to simulate the environment inside her mom’s pouch. We carefully bathed her sensitive skin, monitored the environment, and kept our voices low and her bottle feedings on time as we patiently waited for signs of development.

Peek-a-boo, Tinka!

The first subtle sign of change came in mid-July, when we noticed her right ear standing up a bit better. Her left one stubbornly lagged behind and remained pinned, giving her a comical, lopsided look for a while. Next came a few downy-soft whiskers above her eyes and around her muzzle. By the end of July, there was a subtle darkening of the skin along her back, on her muzzle, and top of her head. Then, a miracle of sorts: Tinka began to sprout fine peach fuzz in the darkened areas. We were delighted with these developments but remained downright superstitious about naming Tinka. She was still so tiny and helpless; we had a long way to go.

A bottle with a special nipple is used to feed tiny Tinka.

Tinka became somewhat of a princess, resting in her cozy pouch just waiting for the next bottle and more attention to arrive. She used her tiny hands to push away an unwanted bottle or kicked and hissed when grooming went on a little long. We offered Tinka water by a syringe to prevent dehydration, which she alternatively loved and gratefully accepted or utterly rejected by a lofty turn of the head. We discovered that she had many interesting ways of communicating her likes and dislikes (the latter category being larger than the former!) with her caretakers. She had us all willingly stepping and fetching.

By mid-September, Tinka’s peach fuzz had become fur. We looked back on those early photos of her when she was pink and totally naked and couldn’t believe she ever looked like the strange pterodactyl-like creature.

Janet and Tinka have a bonding moment.

Now Tinka could stand and hop around a little on her own. She began using the small vertical slit in the pouch to enter and exit as she pleased, although her first attempts were upsetting because getting out was easier than getting back in. We helped her a few times, and she soon got the hang of it.

Our Tinka was growing up, and now it was time to switch gears. Life in the pouch was about to change…

Janet Hawes is a lead keeper at the San Diego Zoo.

10

A Pocket Full of Fun: Parma Wallaby Baby

This photo was taken just 10 days after Tinka was found on the ground, ejected from her mother's pouch.

We are very pleased to be able to show off our beautiful little parma wallaby baby here in the San Diego Zoo’s Neonatal Assisted Care Unit. Though little Tinka (an Aboriginal name meaning “daylight”) has been with us now for nearly three months, we have kept her out of the public view to provide the proper care for her.

Here's Tinka when she was still in her mother's pouch at about six weeks of age. Photo taken April 7, 2011.

Our veterinarians and nutritionists were keeping a close eye on Tinka’s mom, who was losing weight and had some health problems. They knew that this female had a young joey (baby) in her pouch, so she was monitored closely for several weeks. (It was estimated that the joey was born on February 22, 2011, and crawled up into her mother’s pouch soon after, as all marsupial joeys do.) On the morning of July 5, keepers found a tiny female joey weighing only 71 grams (only a little over 2 ounces!) lying on the ground at the morning check. The hairless baby had been ejected from her mother’s pouch and was dirty and cold. Veterinarians were alerted and the animal was immediately transferred to the Zoo’s Jennings Center for Zoological Medicine.

Meg Sutherland-Smith, D.V.M., was on hand to attend to Tinka. She examined the baby, carefully rinsed the dirt from Tinka’s eyes, ears, and mouth, started her on antibiotics, and gave her some fluids. Tinka was soon strong and stable enough to be transferred to the Neonatal Assisted Care Unit in the Zoo’s Children’s Zoo for further care.

Pouch young like Tinka that have been orphaned or rejected provide us with some special challenges. Since marsupials are born very tiny and unformed (about the size of a kidney bean), they continue to develop inside the mother’s pouch after birth. Once ejected from Mom’s pouch, we must offer a substitute because these fragile youngsters will not survive without it. We provide an artificial pouch developed and designed by the Melbourne Zoo in Australia. The pouch provides a place where the baby feels safe and secure. It is suspended in an incubator so the young animal will be kept warm and moist. Since the skin is hairless, fragile, and thin, we must care for and maintain it. We apply a special lotion and take care to keep everything immaculately clean.

Next, since these petite babies have such a tiny, narrow palate and shallow suckling response, they require a unique nipple. The marsupial nipple is soft, long, and narrow. In addition to the special nipple, we also have to provide a particular artificial milk formula. This formula comes to us all the way from Australia and is formulated specifically for marsupials.

To further simulate the environment of the pouch, we must keep the environment calm. Lights are dimmed and voices are kept low. Young joeys can be prone to stress, so we try to take tender, empathetic care at all times. We disturbed Tinka only at bottle-feeding times, which took place every three hours around the clock for weeks. We tenderly bathed her sensitive skin, applied lotion, and monitored the incubator environment carefully.

Tinka soon learned to communicate with us with a series of soft vocalizations and body gestures. A miniscule hiss meant that she was not pleased with our cautious labors, and a shove with her miniscule hands told us she had had enough formula. We soon found out that for one so small, Tinka has a lot of personality and an opinion on every subject!

Janet Hawes is a lead keeper at the San Diego Zoo. Read her previous post, Little Guenon and Mother.

Note: Janet will send us another post describing Tinka’s development. In the meantime, we have a video of Tinka, now 7 1/2 months old, if you would like a “sneak peek.”

Update: Ten new pouches for Tinka have been purchased! Thank you to all who contributed on our Wish List!

0

Puzzles for Tree Kangaroos

A tree kangaroo works a puzzle feeder.

A tree kangaroo works a puzzle feeder.

Part of my enrichment study is to encourage naturalistic behaviors of the marsupials I am watching (see post, Monkeying Around…with Marsupials!). For example, animals in the wild don’t have their food provided for them at regular times each day. Instead, they have to go out and find food for themselves. Some days, food may be easy to get while other days they may have to search longer, dig, or even use tools to get what they need. And other days they may not even find food at all. This is not a bad thing, however, because having a challenge builds the knowledge and skill set of an animal and can make it that much more successful the next time it has a hard time finding food.

To imitate this type of feeding, the tree kangaroos at the San Diego Zoo were presented with a similar challenge. They were presented with a new enrichment item, a puzzle feeder, in which their folivore biscuits and browse (the leafy part of an animal’s diet) were hidden. Getting out the food required a much more complex thought process than getting food presented in a specific feeding location. But the tree kangaroos took up the challenge and succeeded! Because the browse was sticking out of the feeder and was visible, they quickly realized that the large gourds (the puzzle feeders) in their exhibit were more than just “decorations.” Soon after investigating the gourds and extracting some of the browse, they realized an even greater treasure to be gained: folivore biscuits!

A tree kangaroo uses the rope to pull up the gourd puzzle feeder.

A tree kangaroo uses the rope to pull up the gourd puzzle feeder.

Their investigation of the puzzle feeders quickly advanced from simple sniffing and pulling at browse branches to gripping the feeder holes with one hand and extracting biscuits with another. One of the most impressive methods of investigation involved using the rope that the feeder was suspended by to pull the feeder to them. After pulling the feeder up on the log, they had better access and could more deftly extract their favorite treats.

This enrichment was a learning experience for both the tree kangaroos and me. The tree kangaroos had the opportunity to discover new skills that can be used to acquire desired items that are more difficult to access. I learned that even though this enrichment was challenging, tree kangaroos use trial and error to figure out which behaviors worked and which didn’t to get what they need. In the end, the tree kangaroos were not puzzled at all!

At this point, I’m half way through my data collection, and I’ll check back before I leave to update you on some final results of my marsupial enrichment study. It’s fascinating to me how an animal enrichment study has now enriched my understanding of animals!

Lauren Kline is a Bonner Summer Student Intern in the Behavioral Biology Division at the San Diego Zoo’s Institute for Conservation Research.