Captive critters watch their weight, too

If a man were to gain nearly one-third of his body weight in a matter of weeks, doctors might suggest a radical change of diet.

When the Tennessee Aquarium's penguins do, it's no cause for concern, said senior aviculturist Amy Graves.

The 20 gentoo and macaroni penguins in the aquarium's Penguin Rock exhibit carry extra weight about six months of the year during molting and breeding seasons, Ms. Graves said.

"I don't do anything specific to keep anybody trimmed down, (but) I do monitor their weight very closely," she said. "Most of the time, the penguins need to be on the plump side."

Even in the animal kingdom, however, there's big, and there's too big.

With food readily available and limited space to move around, obesity is a real concern for captive animals, said Chris Keller, the aquarium's veterinarian. Obesity can cause problems for animals, including skin conditions, impaired eyesight, diabetes and heart disease, he said.

Understanding a captive animal's biology is key to determining a proper diet, caretakers said.

"When we're able to come real close to approximating their normal diet, we're typically able to reach the goal of having their nutritional needs fulfilled," Dr. Keller said.

The aquarium has a fully equipped kitchen with a pantry and freezer stocked with fruit, krill, squid, dead mice and trays of chilled mealworms for its animals.

Even fresh items might not provide all the vitamins an animal gets in the wild. To fill in the dietary gaps, keepers fortify the food with a dusting or injection of additional nutrients.

Zookeepers must find ways to keep animals intellectually and physically stimulated at feeding time, said Darde Long, the Chattanooga Zoo's executive director.

These "enrichment" activities include stuffing food or other interesting items into two-liter bottles for animals that can manipulate items with their front paws, suspending meat or toys from ropes for the big cats to claw down and mixing sunflower seeds with straw in cardboard boxes for primates, Ms. Long said.

"We do things like that to keep the animal moving around the exhibit and use the full space and stay active," Ms. Long said.

Zoo keepers log notes on the animals' responses to these activities to determine how well they react to different stimuli, Ms. Long said.

Ms. Graves at the aquarium said the logs also record observations about personality quirks, for instance, some snakes won't eat in the open or that a particular penguin prefers to have fish thrown to it rather handed to it or left in a dish.

PICKY, PICKY, PICKY

Just like humans, some animals have strange eating habits:

* The penguins at the aquarium's Penguin Rock exhibit prefer straight fish over bent ones.

* At the Chattanooga Zoo, Hank the chimpanzee doesn't like whole fruit.

* Some of the aquarium's snake and fish species won't dine while on display but must be removed to a smaller cage or provided with cover to eat in private.

* The African crowned cranes at the zoo love to unearth mealworms thrown into their enclosure and allowed to burrow underground.

who's COUNTING?

* 30: Pounds a black bear gains per week when preparing to hibernate

* 95: Percentage of a giant panda's diet that consists of bamboo

* 100 times: How much faster a hummingbird's metabolism is than an elephant's

* 200: Pounds a blue whale calf gains every day while nursing

* 30,000: Number of ants an anteater can consume in a day

Source: National Geographic, Journey North, PBS and Smithsonian National Zoological Park

SHARE YOUR STORIES

Have you lost a lot of weight? Tell us how you did it. Share your success stories, frustrations, diet and exercise tips, before-and-after photos, recipes and questions and story ideas. E-mail us at news@timesfreepress.com and please out "shape" in the subject line.

MORE ONLINE

At timesfreepress.com/news/shape, find a BMI calculator, a nutritionist's column, a dieters' blog, dieters' success stories, FAQs on obesity and links to Web pages with information on healthy living.

Chattanooga Times Free Press features reporter Casey Phillips spoke with local exotic animal specialists about what it takes to keep captive animals at a healthy weight.

CK: Chris Keller, veterinarian at the Tennessee Aquarium

AG: Amy Graves, senior aviculturist at the Tennessee Aquarium

DL: Darde Long, executive director at the Chattanooga Zoo

CP: What is the No. 1 concern for you and your keepers when it comes to the diet of animals in your care?

DL: I think the most important thing is to make sure we meet their nutritional requirements. That sometimes can be challenging because in the wild, they have a certain diet that's available to them. For instance, a carnivore consumes a lot of the animal that it kills. They get calcium from the bones and other resources from blood and meat. So if you just feed them hamburger, that's not appropriate. That may give them the meat they need, but it doesn't give them all the nutritional requirements.

Fortunately, we're blessed in this industry because there are a number of companies that specialize in making food for exotic animals. They allow you to work with them, and they can help you decide what the best course of action is. There's all kinds and sorts of feed out there. It's amazing when you start looking through what's available. In Missouri, there's a company that's got a plethora of everything from leaf eater biscuits to small carnivore chow to omnivore chow to rodent chow. The list goes on and on. There are a lot of specialty chows that make our job easier because they formulate them from years of research. It's helpful to have that stuff available.

CK: The primary thrust of this is to mimic what their diets would be in the wild. It's very important for us to understand the natural history of the animal out where they live. When we're able to come real close to approximating their normal diet, then we're typically able to reach the goal of having their nutritional needs fulfilled. Lots of times, in captive settings, they don't have the same types of stresses or exercise regimens they would in the wild. On top of all that, you don't want to deal with them becoming obese. When an animal becomes overly heavy or fat, there's a great tendency for them to develop additional health concerns they wouldn't normally have.

CP: Do you find that's a resource many institutions like yours use?

DL: Yeah, there are a number of different companies that make carnivore diets, which is one of those things that vary from place to place. There are lot of places that make it, but a lot of times, it comes in this five-pound roll that's packed with all the nutrients that a carnivore needs. These vendors attend our conferences and give presentations. There's a lot of information out there you can tap into, which makes it helpful.

CP: So basically, you can go online and order lion chow?

DL: (Laughs.) Pretty much. There's a lot of opportunity out there to do just that sort of thing. For instance, we just received a pied tamarin that's going on exhibit in about 30 days, and she has a gel she eats that's a mixture of two different chows. That's something they just happened to formulate at the zoo she came to us from that worked really well for her. Sometimes, zoos will put something together when an animal is not doing well. It might just be the animal's overall makeup that's keeping it from doing well.

They'll experiment some and find different things that work. I'll tell you, it's got to taste good; you've got to make sure the animal eats it. That's one of the challenges. For instance, sometimes, the monkeys will not want their monkey chow. Instead, they'll want fruit, so we'll have to encourage them by providing small amounts of fruit for enrichment and variety while also making sure they get what they're supposed to from their diet. It's kind of like Purina dog chow. It's a complete dog food. The dog doesn't need anything else. Oftentimes, the animals will get bored very quickly if the diet is too much of the same thing.

CP: Clearly, there's more to maintaining a healthy diet than just what the animal eats. You just mentioned enrichment. What is that?

DL: It's really an important thing that we do because animals in captivity obviously don't have to forage for food very much. In some larger zoos with larger exhibits, they might do that naturally, but most zoos don't have huge ranges for animals. Foraging is a natural behavior, and it's really important. Lots of animals spend hours a day hunting for food. Having it brought out to them once or twice a day and dumped in the middle of the exhibit doesn't really encourage them to move around and hunt for it. One of the things we do is hide it all over the exhibit and make them look for it.

We'll put it up a tree or an artificial rock or something so they actually have to climb for it. Sometimes, you'll see strings hanging from things in the zoo, and those are ropes we attach enrichment items to so that, for instance, a cat might have to stand up on its back legs and claw at it so that it comes down. We hide it in boxes, so you might see cardboard boxes in our exhibits. We've got food items hidden inside with a bunch of straw or newspaper so they'll have to dig and uncover it. Sunflower seeds are hard to pick out of a big box of straw, but that's the idea. We want the animal to do just that, to forage through the box. We do things like that to keep the animal moving around the exhibit and use the full space and stay active, which is important, too.

CP: Can an animal’s emotional state cause it to gain weight?

AG: The only thing that happens in here is right before breeding season. There's a huge increase in feeding for the penguins, so I know that the season is getting close. About a month out, the food pans will start emptying, and I'll start putting out more food because they're wanting to add those additional pounds before breeding season so they look their best before the breeding season comes on. They'll gradually drop that off. Right before molting season, they gain 20-30 percent of their body weight in a matter of weeks. They get huge to the point where you can be gone for a weekend and come back in and say, “Ah, you're huge.” They get a little sag between their legs and waddle more than normal. They have to have that because, during molt, which lasts 2-3 weeks, they don't eat during molt and don't swim because their feathers are compromised. They live off the fat they've stored up. At the end of the molt, they're back to their slim, trim weight with their new feathers.

CP: The keepers get to know the animals as individuals with personalities. What role does their observation play in determining an animal's diet?

DL: They're absolutely essential because they have to determine what really works. Putting it in a box and determining if the animal is even interested in the box is really important. Some animals respond very well certain types of enrichment, and some animals don't. You have to do different things until you hit on those things you know the animal is going to enjoy and participate with. Some animals will turn their nose up and walk away if it's something that's too hard, for instance. We experiment a lot and vary the enrichment because enrichment itself can become routine if you do the same thing every day.

We do things like give them whole watermelons to burst open. The possibilities are sort of endless. We use a two-liter bottles to pack fruit in and freeze fruit in the summer time so that they have to pick through it and it's a challenge to get into it.

They keepers have to watch them do it and also keep enrichment logs that other keepers can go and look at to see what's working. The cougar eats cardboard, which can cause digestive problems, so he doesn't get anymore cardboard. (Laughs.)

CP: In the larger tanks is there a lot of … intra-feeding between the animals?

CK: There are predator-prey relationships that take place. We feed our animals really well, but there's always going to be that instinct, that drive for predators to attack prey. To be honest with you, when you have a facility like this and you're trying to manufacture their wild environment as closely as possible, a little bit of that is a good indicator that you're doing OK with that. If the animals are acting like they would in the wild, that's kind of our goal. That means they're going to reproduce; that means they're going to be healthy; that means they're going to have, psychologically, what they need. A little bit of that is good. We don't want alligators grabbing turtles in front of kindergarten kids or anything like that, but you have to appreciate that when you have them in as close to a wild setting as possible, some of that is going to happen.

CP: Are there any animals that are notoriously finicky eaters or have strange eating habits like that?

DL: Hank (the chimpanzee) doesn't really like his fruit whole, but he'll eat it. The other chimps in the group could care less. They'll eat anything you put in front of them. Peanut butter is good enrichment because you can smear it on things, and they have to sniff around it. Some animals really don't like peanut butter, so that doesn't work for them.

We even do things that are non-food items, which is also important because if you're talking about obesity, if you continually use food, it can be an issue. Sometimes, especially for our carnivores, we'll use perfumes we drop out in their area. The odd smell attracts them, and they'll roll in it or something like that. We might try different scents with animals that hunters use. Sometimes, they'll use different types of urine and drop it around. That's fascinating when an animal smells a smell from another animal they can check out. Sometimes, we'll alternate and put a different animal in an enclosure.

Right now, we have some arctic foxes we're just holding that were recovered from a puppy mill rescue. We're holding them in our Asia building in a separate den area. They alternate and go out at night in the area where our Hanuman langurs go. The langurs are primates, so when they go out, they can smell that a carnivore has been there, which is intriguing. Conversely, the foxes can smell where the langurs have been. That's something that will keep them busy and exploring for awhile.

AG: This colony is. I don't know if all Gentoos and macaroni penguins are. They don't particularly like bent or crooked fish, for whatever reason. They will eat it, if they are really hungry and they're desperate, but for the most part, they prefer the nice straight ones first. That's about the only finickiness I can think of with them. They do love their smelt and their silversides. That's almost like getting your desert first. It's nice to give them a good mix of sea food to give them the nutrients at a good high level as close to what they would get in the wild as we can. We also feed them krill, so they get at least four different, maybe five different, sea food items, depending on the time of year.

CK: You were talking about their appetites and how they change, but there are also a lot of things you have to reconcile with animals when you have animals in captivity, whether they're reptiles or fish or otters or whatever. You want to make sure you provide them the security they need to eat well. Some animals don't want to eat with bright lights or a bunch of people looking at them. Snakes, for example. We have one particular snake that doesn't like to eat unless it's put back into a small enclosure. Then, it's able to eat relatively well.

The same thing occurs with fish. Some of them require cover and places where they can tuck in and hide because that's what they would be doing in nature. When you think about fish, in particular freshwater fish, the water they live in is torrid and cloudy without much visibility, but here, it's crystal clear. It's pretty freaky for a fish when they first get put in an enclosure with this bright, well-lit, totally clear water and be expected to automatically snap to and realize it's time to eat. These are thing you have to address to slowly acclimate them to captivity.

CP: What are things your or the keepers look for to determine whether an animal has dietary or weight issues?

DL: (Laughs.) We do a lot of weighing for animals we can weigh. Some of our animals are scale-trained and go into a crate we can weigh. It's really important that we get weights on those we can. We can't weigh our chimpanzees as often, but for the animals we can weigh, we do, because it isn't always easy to look at an animal and evaluate its overall physical condition. We have a couple of pretty overweight raccoons. Part of that is because we have a group of four, and they eat together, and two of them are just more aggressive about getting to the food and a lot older, so they don't move around as much. They try to get in and make sure they're not eating the bulk of the food. Yeah, we have a couple of raccoons that aren't following our nutritional plan very well.

CP: How do you combat that?

DL: Sometimes, we have to pull animals and feed them separately. In some cases, we do that anyway. We'll separate them in their dens at nights, and that helps us make sure. If an animal does live in a group setting, like with our raccoons, you just have to watch and pay attention. That observation from the keepers is important. If they notice an animal is getting pushed away, we might pull that animal for feeding or work the exhibit so we can separate that animal while it eats.

CP: What are some side effects of a poor diet?

CK: A couple of things you would think about immediately is that, if they're deficient of vitamins and minerals in their diet, there are a lot of vitamin deficiencies that can manifest. They'll have problems with their eye sight or their skin or, in the case of the penguins, with their feathers or, with mammals, their fur. Certainly, the skin and coloration of fishes and other animals we house here would be affected by certain deficiencies in their diet. Lots of times, we have to supplement them because we can't feed them freshly caught fish or vegetables as often as they get in the wild. Typically, we'll use some other types of things to supplement their diet to make sure they're not lacking any of those minerals or nutrients.

CP: As far as the environment the penguins are kept in, what are some things you do to make sure the penguins are kept at a healthy weight?

AG: I think they do a pretty good job of regulating their own food. I don't do anything specific to keep anybody trimmed down. I do monitor their weight very closely, especially at this time of year when they're coming out of molt. Some of them are on the thinner side, which is very common coming out of molt. So I do observations to make sure they're picking back up and starting to eat again and putting back on the weight. I don't have to worry about over eating. Most of the time, the penguins need to be on the plump side because of the cold temperatures they're in. That fat and their feathers keep them protected from cold temperatures.

CP: Are there any sedentary animals at the aquarium for which lack of physical exercise is a concern?

CK: Absolutely. As far as categories of animals that tend toward obesity, we have a lot of concerns with fish. There's a disease called fatty liver and several other things that impair their physiology. They can become quite ill with it, and it can shorten their lives. With reptiles, you have concerns with turtles and snakes becoming overweight, because frankly, if everything's provided for them, they don't have to go very far to hunt and find prey items and don't have very large enclosures to clamber around in. There is a possibility obesity could be an issue for them. You do want to feed them on a regular and defined basis so you don't have problems with snakes becoming too rotund and having diseases associated with that.

CP: If you notice that a certain species that was new to the aquarium wasn't eating properly, that's something you would consider straight off?

CK: That's one of the things we'd consider right away. Having been at this the better part of 20 years, when animals come in, either from the wild or from other facilities, when they're put through a quarantine procedure. Quarantine is done on every single animal that comes through the door here. You give them at least 30 days to make sure they are free of diseases and do tests on them. That's what keeps the facility successful, when you adhere closely to quarantine.

One other thing that happens is that, let's face it, it's a sink-or-swim kind of philosophy. Animals do have diseases, and it's that stress of the transition from the wild to captivity that makes them manifest those things. In quarantine facilities, for fish, especially, a lot of the ones that have secluded behavior or do a lot more hiding, we need to put a lot more cover in the environment. We'll put tops over them to make the tanks dark or put PVC pipes to simulate coral or brush that freshwater fish might go into to try and give them the kinds of things they need to have the well-being they need to eat and thrive in quarantine. We want happy fish.

CP: What are the animals that eat the most or the most often? The least, the least-often?

DL: For the most part, we do pretty well. On occasion, we'll have an older animal that starts to lose weight just because it's older and not able to process food as well. In that case, we'll consult with our vet and start using a vitamin supplement or increasing the amount of food or making the food richer, if we need to. Some of our older animals have dental issues where their teeth are starting to not be as good, in which case we'll grind the food up. We've made mixtures with yogurt. We'll make a pudding of that and a chow mixture and add in yogurt or applesauce to make it more palatable and encourage them to eat.

CK: Butterflies eat an awful lot, relatively speaking. They eat all day long. Certain snakes, on the opposite extreme, we might feed as infrequently as once every two weeks or even every month, depending on their obesity and what we're trying to do with them. Certainly, those animals are set up, physiologically, to consume prey very infrequently. On the flip side of that, many of the insectivores, if they don't eat all the time, almost constantly, it's difficult for them to maintain the physiological state they need to do well. There's this kind of juxtaposition of those two on the opposite extremes of the spectrum, but they're both reptiles.

Look at birds, there are some that are more laid back, but birds have to get pretty much fed all the time and every day or they're not going to do well. When you listen to their heart, their pulse rate is in the 300s, and they're nervous and edgy and very interested in getting away from you and fleeing. Then, you put the stethoscope on a turtle, and his pulse rate might be 30, and he's perfectly fine. If you look at the animal and analyze what they're supposed to do, what they're built for, you can really get an idea of what their diet is going to be and how often they'll eat.

CP: So it's not just hauling out a slop bucket in the morning and thinking that's it.

CK: You have to understand every single individual's natural history. That term refers to what their life is like in the wild. If you don't get an idea of that, then you're getting in trouble. If you're talking in private practice with people who have exotic animals as pets, whether that's snakes, birds or lizards, I can stand in an exam room and ask where these animals came from, and the owners don't know. No wonder the animal is sick. They don't know what they eat; they don't know where they come from; they don't know what the conditions are like where they live. Of course they're going to have animals that don't do well because they don't have an appreciation of what that animal needs in the wild.

AG: Many times, when we acquire an animal from another zoo or aquarium, we will get a sheet that comes with it from the keeper or staff member who took care of that animal. I had one on every single penguin. It would say things like, “This penguin will hand feed. This penguin eats best in the water. This penguin will do both.” And “Watch out for this.” Whenever we acquire an animal, not only do we have to do the research of the natural history of the animal, but it helps to have the keeper that's been taking care of it send you a few notes to let you know right off the bat that “if you try and feed this bird, it's going make him more uncomfortable, toss the food to him from a few feet away.” It makes all the difference in the world and helps with the transition from one institution to another.

CP: So you'll have to do the same for the chick that was just hatched at the aquarium earlier this summer?

AG: Exactly. As he grows and gets bigger, we're already learning a few things about him. He has his own quirks about what he likes and doesn't like. If he gets transferred to another institution, that's exactly what we'll fill out. “He hatched here. This is how we raised him. This is what he enjoys.”

CP: Dr. Keller, you mentioned turtles earlier. What do turtles tend to eat and do they ever have weight problems?

CK: We have a pretty large collection of turtles, and the individual variation from one species to the other is quite extreme. We have some that are almost exclusively fish-eaters to the ones that are almost exclusively vegetarian, like the tortoises. There is a wide, wide range. Ironically, one of the things we always have to deal with with our animals is that sometimes, within the same enclosure, we have multiple dietary needs.

For example, within the big salt tank, we have sea turtles, and sea turtles should really be eating a diet that mimics what's going on in the wild with more vegetation in algae and seaweed and things like that. Occasionally, though, they luck onto a piece of fish or some other source of protein that they're able to gobble down. That makes them want that more, so in a captive setting, when we feed the fish, we have to be careful the turtles don't overeat the protein they strive to acquire in the wild. Here, it's available every day. We really don't want that. We want them to try and eat what they would in the wild. We have to deal with that obesity issue because of that with the sea turtles.

CP: How do you tell if a turtle is obese?

CK: The fat rolls out around their shells. Their necks get big and fat. They'll have fat around their tails and their rear legs. Of course, you also weigh them. You don't have a formula or anything, but you can look at them and go, “God, he's 10 percent overweight,” just from looking at him and put him on a more austere diet. In the big saltwater tank, we target feed the sea turtles. We have a PVC pipe that has tape with different colors on it that the turtle is trained to come to when it's dinner time. We hang broccoli and lettuce on PVC pipe and lower it into the tank so they have that opportunity to get vitamin A and calcium and things in higher concentrations in green, leafy vegetables than are in prey items. Then, they're individually fed in a separate tank that's an offshoot of the main tank using tongs. We're able to give them pepper and romaine lettuce and things like that that technically would be healthier for them along with a few pieces of squid or fish or shrimp. They opportunistically eat a lot of stuff when the fish are fed as well.

CP: Do you fortify those vegetables like you do some of the other foods?

CK: We don't do that. That's one of the advantages of feeding fresh vegetables. A lot of times, that's left out of the diets of captive animals in pet situations because it's a lot easier to buy a thing of iguana food than it is to go to the store and buy things we know to be fresh. The fresh foods have the better proportions of vitamins and minerals. What you see is what you get when you get a piece of lettuce or broccoli or whatever. When you buy stuff that is commercially prepared, you don't have that luxury. Gosh knows what's in it. They might have the crude analysis on the back, but that doesn't mean that's exactly what's there.