NARRATION After recess, it's time for math class. On Scientific American Frontiers ... find out how smart animals really are. Also ... People -- and computers. Can you always tell them apart? An endangered woodpecker gets a new lease... on life. And engineers put a new twist into the rollercoaster. Come along for the ride, on Scientific American Frontiers. WOODIE FLOWERS Hi. I'm Wood ie Flowers, and welcome to Scientific American Frontiers. Daisy, come. Now most people teach their dogs to bark on command - you know, I say "Speak" and Daisy says "Woof". But we like it quiet - so we tried another tack. Daisy -- whisper. Cute, huh? And it didn't take her long to learn that. In fact, I think Daisy learns faster than we do. Watch this. She figured out, before we did, that returning the toy just out of reach would get her some extra attention. I guess everyone who has a pet must sometimes won der just what's going on inside that animal's head. The problem is, how would you ever find out? After all, you can't very well just ask an animal. Actually, it turns out you can, if you're clever enough. And our first story is about two people who've come up with some ingenious ways of getting animals to reveal just how smart they can be. SMART TALK IRENE PEPPERBERG I've got to go eat dinner. Gonna put you in, okay? You be good. ALEX You be good. IRENE PEPPERBERG Okay. I'll see you tomorro w. I'll see you then. ALEX Bye. IRENE PEPPERBERG Bye. NARRATION Irene Pepperberg is a professor at the University of Arizona. ALEX I love you. IRENE PEPPERBERG I love you, too. Bye. NARRATION And one of her top students is an African gray parrot named Alex. Like many parrots, Alex is a virtuoso mimic. ALEX I'm sorry. You're a good boy. I love you. NARRATION He doesn't understand what he's saying, he's just parroting. Or is he? MAN Come on, what is it? ALEX Keychain. IRENE PEPPERBERG Good birdie. G ood parrot. NARRATION The extraordinary thing about Alex is that very often, he does understand what he's saying. IRENE PEPPERBERG What is it? ALEX Rock. MAN Good boy. IRENE PEPPERBERG Yeah, good birdie. Alex, what toy? ALEX Nail. IRENE PEPPERBERG N ail, that's right. You're a good birdie. You're a very good boy. MAN What toy? ALEX Truck. IRENE PEPPERBERG That's right. MAN You're a very good birdie. IRENE PEPPERBERG Tell me what color. What color? ALEX Yellow. IRENE PEPPERBERG Yellow, that's ri ght. MAN What matter? ALEX Wood. MAN Good. That's right. Very good. IRENE PEPPERBERG How many? Good boy. How many? ALEX Two. IRENE PEPPERBERG Good parrot. Good boy. One. Two. NARRATION Alex is even smart enough to answer different questions about th e same objects. IRENE PEPPERBERG Can you tell me what's different? What's different? ALEX Color. IRENE PEPPERBERG Good boy. All right. What same? What same? ALEX Shape. IRENE PEPPERBERG Good boy, good birdie. What color bigger? You know. What color bi gger? ALEX Yellow. IRENE PEPPERBERG Good boy. Good birdie. NARRATION If you still think Alex is just parroting, watch this. IRENE PEPPERBERG Look. What matter four - corner blue? NARRATION Alex has never been asked this question before. To answer it, he examines all the objects on the tray. There are several 4 - cornered objects, and several blue objects, but only one that's both 4 - cornered and blue. Alex's job is to say what that one object is made of. crushing the birds sheltering inside. It's this destr uction of the woodpecker's homes - even more than the loss of the birds themselves - that was the most devastating of Hugo's blows to the species. Because the red - cockade woodpecker's home is definitely not just a hole in a tree. To find out why the red - co ckade woodpecker's nest is so special, Frontiers came here, to Mississippi's Noxubee Wildlife Refuge. It's early in the morning - the best time to catch a woodpecker. Noxubee - another of the few scattered old growth pine forests of the south - currently i s home to just forty - one woodpeckers. White bands mark trees with woodpecker holes. The question for Jerry is whether the bird in this tree is sleeping late. JERRY JACKSON Hey! We got one! NARRATION If this is a female, then she's the only one at home. T hat's because males and females keep separate living quarters - and it's the father who nests with the babies, while the mother sleeps off by herself. JERRY JACKSON Oh, this is a bird that has bands on it, so we've got us a recapture. We'll be able to tel l how old this bird is and when it was banded. NARRATION And its sex - because only the males have the red cockade. JERRY JACKSON They only show these red - cockades when the birds are aggressive or courting. This bird's a little aggressive right now becau se he doesn't really like being caught. NARRATION Because it's a male, there are probably babies in the tree - and their hungry cheeps give them away. Both male and female share the feeding chores during the day. JERRY JACKSON Well, get back to your nest , fella. NARRATION So here's the first reason the holes are valuable - each family needs two. The second reason is visible around the hole itself - sticky sap, looking like candle wax. The sap is there because, unlike other woodpeckers, red - cockade woodpe ckers choose to make their holes in live trees, not dead ones. And making a hole in a living tree is hard - very hard. JERRY JACKSON The average length of time that it takes for a red - cockade woodpecker to excavate a cavity is four point seven years. As a result, those cavities are extremely valuable pieces of property, and they're passed down from generation to generation, and the males inherit them. NARRATION Four point seven years' work per cavity is quite a mortgage to pay off - and it raises the ques tion: Why? Why do red - cockade woodpeckers drill through live sapwood, while other woodpeckers just peck their way through dead wood? And here's the answer - the gray rat snake. It's a superb tree climber, its scales giving it an excellent grip on the bark. But around the nest hole, the woodpecker has pecked the bark to keep the sap flowing. As the snake approaches its goal - a succulent meal of eggs or nestling - the waxy sap gets thicker and thicker. The sap works its way between the snake's scales, sticki ng them together. But if the sap protects against snakes, it doesn't keep biologists away. Fortunately, Jerry's motives for climbing the tree are more benevolent. While the parents are away gathering food, Jerry plans to check on the nestling. This is a th ree - week old female. She's banded, then weighed -- during which she gets her first real look at the world she'll soon be joining. Jerry's work is part of a detailed monitoring of the birds here in Noxubee from birth to death. JERRY JACKSON That about does it - forty - five point three grams. This bird is very close to fledging. You can see it has very well - developed wing feathers, but that the wing feathers are still growing. And those feathers will be completely grown probably within the next week, and this bird will be out of the nest by then. NARRATION Out of the nest - and needing one of her own. Her home nest will be inherited by a brother. Fortunately, in Noxubee, there are still a few trees to be drilled, a few homes to be had. But back in the Francis Marion National Forest, Hurricane Hugo crushed hundreds of woodpecker homes. With so many trees destroyed - ironically, snapped in two often because they contained woodpecker holes - the shortage of homes is acute. And because it takes so long to make new cavities, wildlife managers here feared that the seven hundred birds surviving the hurricane would die homeless. So in the spring of 1990, they went into the construction business. Biologist Carolyn Bachler first drills a horizontal hole, just as the bird does. Then she drills a second hole at an angle from above, to create a vertical cavity down through the middle of the tree. The idea is to reproduce in a few hours what it takes a bird over four and a half years to make. BOB HOOPER Here's the entrance, here, and it's about nine or ten inches deep. The light - colored wood here is sap wood, and it is living wood and the resin actively flows through it. The reddish - colored wood here is heartwood and it is essentially dead - there's no resin movement through it. The bird needs the heartwood into which to put its cavity so that it doesn't have to contend with resin within its cavity. Carolyn Bachler scrapes off some bark to set the sap flowing. The tree is in move - in condition - but it took half a day's work. H ere's a pre - fab option. This time, the tree is excavated by chain saw. A little putty - and a bird house is slipped into place. Even sap holes are started for the hoped - for tenants. A little paint gives the impression that the sap is already flowing. In al l, over six hundred artificial cavities were built in the Francis Marion Forest over the winter. With spring - and nesting season - came the chance to find out if they worked. Eddie Taylor checks one of the bird house implants with a light and a dentist's mirror. TAYLOR Bob, we've got some eggs. HOOPER Is that right? How many? TAYLOR Got two. HOOPER That's the very first nest. The same nest, three weeks later - and hungry chirping signals that the eggs have hatched. TAYLOR What I'm gonna do is fixing t o pull the nestling out of the nest so we can band them. What I'm gonna use is this little instrument right here. It makes little nooses, and then I'll pull it tight and it'll grab them and I'll pull them out gently. It doesn't hurt the young because their bones have not calcified at this age, and so they're still malleable. And we can handle them gently without hurting them. NARRATION The chicks' eyes aren't open yet - but they can tell the difference between light and dark. And dark means their hole is c overed by Mom or Dad arriving with food. At least that's usually how it is. A nest - by - nest inspection of the trees that remain in the Francis Marion National Forest this spring showed that sixty - five percent of all the new birds were born in the artificial cavities. A band on the bird will help keep track of it in the future. The man - made nests appear to have given the woodpeckers here a new lease on life. But even as this most important population of red - cockade woodpeckers has been rescued from a rare nat ural disaster, the erosion of their habitat all over the south continues. The real threat to the species' survival remains man, not nature. JERRY JACKSON There's a lesson to be learned form Hurricane Hugo, and we're very fortunate we have the opportunity to learn that lesson. And that lesson is that every population is important. And that we can't count on having a few large populations. This is probably the best - known woodpecker in the world. We know what it requires - we know what it needs. We've just go t to make up our minds to do what it needs to protect the remaining populations. back to top THE WORLD'S SCARIEST ROLLERCOASTER WOODIE FLOWERS (NARRATION) I've always wondered what it would be like to jump out of a plane - so I'm going to find out. DIV E INSTRUCTOR Head up nice and high - hard arch. FLOWERS This is fantastic - I hope you guys can hear me. INSTRUCTOR All right give me a left turn, Woodie. FLOWERS Okay. INSTRUCTOR Stop - turn left. FLOWERS Those are nice, swift turns. This is a 3 - D sp orts car. Here I come! INSTRUCTOR 3, 2, 1, flare. All right, good job, Woodie. Wow, I'm sure the guys with the cameras did a great job, but there's no way pictures can do justice to what I just experienced. I knew this was going to be a fun job. NARRATIO N Actually, I spent a whole day training for this, and it cost several hundred dollars. And even though the risk associated with the jump was probably less than that of driving out here this morning, it's pretty clear that sky diving's not for everyone. Bu t a lot of people would like to get the kind of thrill that I've just experienced without spending the time, and the money, and the nerve. And that's the reason that amusement parks are big business - and that's the reason that the designers of rides are a lways trying to outdo one another. We wondered how you would design a ride that was both thrilling and safe - so we've spent over a year tracking the designing and testing of what is - at least for now - the world's ultimate rollercoaster. Three or four ma jor rollercoasters open up every year. And in a never - ending competition to be the best, each is bigger than the one before it. Today, coasters can be twenty stories tall and reach speeds of seventy miles an hour. The coasters are designed to be safe. But their intimidating looks are beginning to scare off less adventurous riders -- according to the designer of this coaster, Ron Toomer. TOOMER I really think a lot of people are going to walk up to that thing, look up there and say, "My gosh, that's too big for me -- I'm not going to get on it." WOODIE FLOWERS (NARRATION) So five years ago, Ron began toying with a brand new concept in coasters. Here's how all existing coasters work. The twists and turns and ups and downs in the track create forces pushing a nd pulling on the rider. That's what makes them fun. But always the greatest force is pushing car and rider against the track -- even when you're upside down in a loop -- and that's what keeps you from falling out. To demonstrate, we joined a high school ph ysics class as they rode a coaster with their own home - made force meters. TEACHER That's going to register on this. When we're standing here still, this is our one unit of force. This would mean that on your rear end, when you're in that car, you'd feel y our normal weight. But as we go around the bottom of that curve, you're going to see this thing pull down to two, three, or three and a half times your normal body weight. WOODIE FLOWERS (NARRATION) For the experiment, each student was supposed to look at and remember the force holding them into the car at different points in the ride. But it proved easier said than done. STUDENTS Too scared to look at it. We didn't look at it - we forgot. Gonna do it again. WOODIE FLOWERS (NARRATION) We made it easier f or us to see by slowing down the action. Entering a loop, there's a force three and a half times greater than normal gravity pushing them into their seats. Even when upside down at the top of the loop, they're being held into their seats by a force two tim es gravity. So at no point do they really feel as though they're upside down. STUDENTS You felt like you were on Earth rather than on a rollercoaster upside down. Didn't have a sensation of being upside down. Except for the visual sensation of looking ups ide down, it felt like you were sitting right - side up. In all existing coasters, that's just as well - otherwise car and riders would fall off the track. Only briefly, at the crest of a hill, does a rider feel like he's coming out of his seat. But what if a coaster could be designed that did a barrel roll -- like an aerobatics plane? TOOMER We're looking for an advancement of rollercoaster technology here that would allow us to feel more like that kind of a sensation where you're able to roll over, fly alo ng upside down, and you really are upside down. You're hanging upside down, you look down and there's nothing below you but the ground - and there's no tracks - there's nothing there to hold you up. WOODIE FLOWERS (NARRATION) It was this new twist in rolle rcoaster design that Ron and his company, Arrow Dynamics, decided to explore. This is an early run of a quarter - scale model. To create the barrel roll effect, the car sits down in the tracks rather than on them, as in existing coasters - and to hold it up when it's upside down, it hangs from a second set of wheels. These are big innovations for a rollercoaster, and when we joined Arrow in the early stages of development, there were still plenty of questions to answer - like just how much initial energy the car would need to avoid the discomfort - and embarrassment - of a problem like this! The main task though, was to stop people from falling out - the job of engineer Dahl Freeman.