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Photo of Suzanne MacDonald Suzanne MacDonald
The Wilder, the Better

Suzanne MacDonald, an animal behaviorist at the Metropolitan Toronto Zoo, creates enrichment programs by applying her knowledge of how animals think and their natural behaviors in the wild. Frontiers viewers asked Suzanne about her work with orangutans, Saki monkeys and other species

q When the animal was displaying his strength to the female, he was scratching his armpit. Is that part of the "display" behavior or was it just a coincidence?

A The gibbon was indeed scratching his armpit, but I think it was just a coincidence. At least I think so -- I've never seen "armpit displays" in gibbons before, but you never know what might be attractive to a female gibbon!

q Are the enrichment strategies you use -- hiding food, etc., -- becoming adopted by most zoos now? Or are these programs limited to a new "cutting edge" zoos like those profiled on this show?

A Hiding and scattering food is becoming widespread in many zoos, both large and small. It's an easy thing to do that makes a big difference for the animals, especially for primates. I think the reason that people didn't do it before is that zoo staff are very careful to make sure that all the animals receive enough food every day, so they wanted to be able to measure it, and observe each animal eating. That's still important, so many zoos make sure that the animals are fed their "real" meal before they enter the public exhibit, and then they can forage for treats and snacks throughout the day. That seems to work best for everybody.

q Why did the saki monkey's mating behavior improve once you starting hiding the sunflower seeds for them to find? The reason wasn't really explained on the show.

A The Saki monkeys' mating behavior improved, and other behaviors did, too. For example, they also started playing with each other more often. I don't know why a simple thing like giving them a foraging game should affect their overall behavior, but it often happens, and not just with monkeys. I think that having something new to do is often enough to break the stereotyped pattern of behavior that the animals are caught up in. The Saki monkeys spent so much time grooming that they got stuck in a repetitive cycle. Introducing the wooden feeders was something so unusual that it broke the cycle. They still groom, of course, but I think now that they have experienced the joys of "normal" behavior, they'll never go back!

q How you design the experiments you come up with, like hiding food in the jugs for the orangutans? Do you start out trying to discover the answer to a specific question with your experiment, or is it generally more open-ended?

A The experiments I do that examine memory in primates are based on specific hypotheses about how primates think. Primates are interesting because there are so many different species, and they live in many different habitats. That lets us look at how the environment they evolved in shapes the way they think. For example, orangutans are solitary fruit-eating animals -- we predicted that they would be good at remembering specific food locations, and that they would not compete with each other over food. Gorillas, on the other hand, live in a social group and they compete regularly with each other in the wild. We did a similar experiment with them, and although they were also good at remembering where food was, they were VERY competitive. So, it turns out that how you think and behave has a lot to do with where (and with whom) you live.

q Have you tried the synthesized mating calls with other animals at the zoo? And, if so, has it worked to produce offspring?

A I haven't tried using taped mating calls with other animals at the Zoo, but I hope to do so, based on the success of the gibbon work.

q In your experience, for which animal is it the hardest to create an enrichment program?

A For me, the hardest animals to create enrichment programs for are the big cats -- tigers, lions, cheetahs, leopards, and jaguars. In the wild they patrol big territories, and it's difficult to recreate that in captivity. That's why you see so many big cats pacing around their enclosures. Also, it's hard to let big cats hunt and kill their prey in captivity -- we feed them meat, but it comes in big chunks (already dead!). So, two of the most important behaviors that big cats do (patrolling and hunting) are pretty well impossible to do in captivity, which is why it's hard to enrich them. We do try to make sure that big cats are in the appropriate social group (for lions, not for tigers, since they are usually solitary), and that they have as much room as possible to roam, with some interesting things to play with (like balls, or water).

q The segment of the New Zoo's that you were in focused on enrichment programs for mammals. For that matter, the entire program touched upon only mammals and fish. What about reptiles and amphibians? Are there any enrichment programs for organisms such as turtles, lizards or snakes?

A What a good question! It is possible to enrich other animals, including reptiles and amphibians, but it certainly is more tricky than working with mammals or birds. Usually, the best enrichment for reptiles and amphibians is making sure they have a "natural" looking habitat, with opportunities to swim, hide under lily pads or rocks, and bask under heat lamps. Also, they must be housed in the appropriate social group -- some animals (like some snakes) are solitary, and some (like some lizards) need to be housed with lots of others. There is some evidence that reptiles may actually play in captivity, which is interesting because they have never been observed playing in the wild. This means that we can provide turtles (and lizards) with objects like balls to play with -- they don't play often, but they do occasionally, so objects seem to provide them with a nice break. But if you can come up with any other ways to enrich reptiles and amphibians, I'd LOVE to hear from you!

q How do you become an animal behaviorist?

A Most animal behaviorists start out with an undergraduate degree in Biology, Zoology or Psychology, and then move on to graduate school to complete a Ph.D. My Ph.D. is in Psychology, but a Biology Ph.D. (with a specialization in animal behavior) would also be OK. A behaviorist usually combines strong research skills (in experimental methods, research design, and statistics) with a background in animal behavior theory, wildlife management, and practical experience with animals (usually in captive and field settings). There are not very many animal behaviorists around, but there will probably be more as people realize that behavior is a very important (and often overlooked) aspect of an animal's well-being, and a very good indicator of overall health. Plus, behavior research is relatively cheap compared to research, say, in genetics or reproductive physiology. All we need is a notebook and a videocamera, and we're set!

q Does the orangutan have a prehensile tail? What color is an orangutans fur? Are orangutan's "insides" the same as a person's?

A Orangutans don't have tails at all! They are Great Apes, not monkeys. Other Great Apes are gorillas and chimpanzees. Gibbons (who were also shown in the program) are called Lesser Apes, and they don't have tails either. Orangutan fur is almost orange in color especially when they're born, although when they get older, it turns darker, and gets rusty brown. Orangutans are just like humans inside -- they have all the same organs (heart, lungs, liver, kidneys, stomach, intestines) that we do. Everything else about them is the same, too -- their mouths have teeth like ours, their tongues are just like ours (and they like to stick them out at people, too!), and their hands have nails and fingerprints, just like ours. The only difference between us and them is that orangutans have shorter legs, longer arms, and longer feet and hands. Plus, they can use their feet like we use our hands, so they can climb and swing from branches MUCH better than we can.

q How often do orangutans mate in captivity? How many babies do female orangutans have at one time? How long do orangutans live?

A Orangutans are Great Apes, so are very similar to humans. Female orangutans have menstrual cycles, like humans do, and so can mate anytime, but can only conceive around the time of ovulation (roughly once a month). They usually have one baby every few years, just like humans do. The babies stay close to their mom for the first five or so years of their lives, but are usually weaned by the time they're two or three years old. Orangutans live about the same length of time as humans do in many countries in the world -- about 50-55 years.

q McKelvie Middle School, Bedford, NH, students will be conducting the activity "If I ran the zoo." We are in need of information regarding animals, and their recommended habitat size. We have searched the internet addresses with no luck on this data. Please address. Melissa Kelly from SAF recommended we ask you.

A I suggest students contact the American Zoo and Aquarium Association ( to ask them. I arrive on the scene after the exhibits are all designed and built, and have to do my best to work with what's there...but the architects and designers might know if there are "standards" for exhibit size for different animals. I suspect that what usually happens is that there is a pretty simple rule in place..."the larger the animal, the larger the space"! I do know that there are standards set for the depth and width of moats within exhibits, to keep the animals from escaping (for example, chimps need a moat 20 ft deep and at least 9 feet wide), but that's about all I can contribute, I'm afraid.

q This question is about introducing the sound of a male gibbon in order to the make the male and female gibbon more interested in each other. I am wondering how beneficial that was as a result of what transpired. The male and female didn't "talk", i.e., make sounds, until the 'competing male' calls were introduced. Then the female's vocalizations began, but you said this was actually not a good thing, since it meant that the female was inviting this new male in at the exclusion of the real male. Both animals eventually vocalized, which was seen as a good thing, but I was confused how this didn't cause MORE animals stress, since the female couldn't have a nonexisting male and the existing male can't compete with something that isn't real. Won't frustration set in? Did these two animals finally become interested in each other instead of the imaginary male?

A The gibbon study is still going on, and has been for the past year or so, so you only got to see a small part of it on the program. When we started, we played a whole range of sounds, including the male gibbon call, just to see what reaction we'd get. We discovered early on that Holly (the female) started calling to the male's taped call, and the Lenny (the male) got really mad at that. In fact, Lenny would often be quite aggressive toward Holly after the call was played -- charging her and even slapping her. We caught on pretty quickly to that problem, so we stopped playing that call regularly, and played the normal male/female duet instead. That seems to have helped them "bond". Interestingly, we played the same sounds to another pair of (very closely bonded) gibbons at another zoo, and the female in that pair did not react at all to the taped call of the strange male. She (and the resident male) did sing along to the tape of their own duet, though, joining in and howling up a storm. So I think we may have a great way to assess the strength of the pair bond in gibbons -- if the female calls to a tape recording of a strange male, the pair bond is not so good; if she doesn't, then the pair bond is very strong and the pair is likely to mate. An unexpected bonus!

q In one segment on the show you were experimenting with how the orangutans remembers where he got his food out of those containers. He knew exactly where to go and then another monkey came in and got to the food first. The first monkey saw this and wasn't even phased by it. Then there was the other type of monkey, the gibbon, where you researched the male synthesized call to the female. On that one the male got all worked up because the female reacted. So my question is, is there that big of a difference between the two types of monkeys that one gets mad and jealous and the other does not? And have you researched that kind of thing, if so what were your results?

A There is a big difference between animal species in terms of "jealousy" (although we don't call it that when we talk about animals because that is a word that only describes human behavior). Some animals, like orangutans, live by themselves, and so don't have much experience fighting with other orangutans (over food, or mates, or whatever). Other animals, like gorillas, live in big social groups, and have skirmishes all the time with each other over who gets to sit where, who gets the tastiest food, etc. There is also a big difference in animals in how much they will fight over mates. Gibbons live with one partner for their whole lives, so they are very attached to each other, and get very upset when other gibbons try to "horn in" on their partners. Orangutans don't do that, because they mate with many other orangs in their lifetime, and so don't play favorites, and don't get "jealous."


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