"
When we consider mass extinction from a meteor impact," Richard Levine said, "we must ask several questions. First, are there any impact craters on our planet larger than nineteen miles in diameter-which is the smallest size necessary to cause a worldwide extinction event? And second, do any craters match in time a known extinction? It turns out there are a dozen craters this large around the world, of which five coincide with known extinctions..
Kelly Curtis yawned in the darkness of her seventh-grade classroom. Sitting at her desk, she propped her chin on her elbows, and tried to stay awake. She already knew this stuff. The TV set in front of the class showed a vast cornfield, seen in an aerial view, the curving outlines faintly visible. She recognized it as the crater in Manson. In the darkness, Dr. Levine's recorded voice said, "This is the crater in Manson, Iowa, dating from sixty-five million years ago, just when dinosaurs became extinct. But was this the meteor that killed the dinosaurs?"
No, Kelly thought, yawning. Probably the Yucatan peninsula. Manson was too small.
We now think this crater is too small," Dr. Levine said aloud. "We believe it was too small by an order of magnitude, and the current candidate is the crater near Merida, in the Yucatan. It seems difficult to imagine, but the impact emptied the entire Gulf of Mexico, causing two-thousand-foot-high tidal waves to wash over the land. It must have been incredible. But there are disputes about this crater, too, particularly concerning the meaning of the cenote ring structure, and the differential death rates of phytoplankton in ocean deposits. That may sound complicated, but don't worry about it for now. We'll go into it in more detail next time. So, that's it for today."
The lights came up. Their teacher, Mrs. Menzies, stepped to the front of the class and turned off the computer which had been running the display, and the lecture.
"Well," she said, "I'm glad Dr. Levine gave us this recording. He told me he might not be back in time for today's lecture, but he'll be with us again for sure when we return from spring break next week. Kelly, you and Arby are working for Dr. Levine, is that what he told you?"
Kelly glanced over at Arby, who was slouched low in his seat, frowning.
"Yes, Mrs. Menzies," Kelly said.
"Good. All right, everyone, the assignment for the holidays is all of chapter seven" - there were groans from the class - "including all of the exercises at the end of part one, as well as part two. Be sure to bring that with you, completed, when we return. Have a good spring break. We'll see you back here in a week."
The bell rang; the class got up, chairs scraping, the room suddenly noisy. Arby drifted over to Kelly. He looked up at her mournfully. Arby was a head shorter than Kelly; he was the shortest person in the class. He was also the youngest. Kelly was thirteen, like the other seventh-graders, but Arby was only eleven. He had already been skipped two grades, because he was so smart. And there were rumors he would be skipped again. Arby was a genius, particularly with computers.
Arby put his pen in the pocket of his white button-down shirt, and pushed his horn-rim glasses up on his nose. R. B. Benton was black; both his parents were doctors in San Jose, and they always made sure he was dressed very neatly, like a college kid or something. Which, Kelly reflected, he would probably be in a couple of years, the way he was going.
Standing next to Arby, Kelly always felt awkward and gawky. Kelly had to wear her sister's old clothes, which her mother had bought from Kmart about a million years ago. She even had to wear Emily's old Reeboks, which were so scuffed and dirty that they never came clean, even after Kelly ran them through the washing machine. Kelly washed and ironed all her own clothes; her mother never had time. Her mother was never even home, most of the time. Kelly looked enviously at Arby's neatly pressed khakis, his polished penny loafers, and sighed.
Still, even though she was jealous, Arby was her only real friend - the only person who thought it was okay that she was smart. Kelly worried that he'd be skipped to ninth grade, and she wouldn't see him any more.
Beside her, Arby still frowned. He looked up at her and said, "Why isn't Dr. Levine here?"
"I don't know," she said. "Maybe something happened."
"Like what?"
"I don't know. Something."
"But he promised he would be here," Arby said. "To take us on the field trip. It was all arranged. We got permission and everything."
"So? We can still go."
"But he should be here," Arby insisted stubbornly. Kelly had seen this behavior before. Arby was accustomed to adults being reliable. His parents were both very reliable. Kelly wasn't troubled by such ideas' "Never mind, Arb," she said. "Let's just go see Dr. Thorne ourselves."
"You think so?"
"Sure. Why not?"
Arby hesitated. "Maybe I should call my mom first,"
"Why?" Kelly said. "You know she'll tell you that you have to go home. Come on, Arb. Let's just go."
He hesitated, still troubled. Arby might be smart, but any change in plan always bothered him. Kelly knew from experience he would grumble and argue if she pushed for them to go alone, She had to wait, while he made up his own mind.
"Okay," he said finally. "Let's go see Thorne.
Kelly grinned. "Meet you in front," she said, "in five minutes."
As she went down the stairs from the second floor, the singsong chant began again. "Kelly is a brainer, Kelly is a brainer…"
She held her head high. It was that stupid Allison Stone and her stupid friends. Standing at the bottom of the stairs, taunting her.
"Kelly is a brainer…"
She swept past the girls, ignoring them. Nearby, she saw Miss Enders, the hall mointor, paying no attention as usual. Even though Mr. Canosa, the assistant principal, had recently made a special homeroom announcement about teasing kids.
Behind her, the girls called: "Kelly is a brainer…She's the queen…of the Screen…and it's gonna turn her green…" They collapsed in laughter.
Up ahead, she saw Arby waiting by the door, a bundle of gray cables in his hand. She hurried forward.
When she got to him, he said, "Forget it."
"They're stupid jerkoffs."
"Right."
"I don't care, anyway.
"I know. Just forget it."
Behind them, the girls were giggling. "Kel-ly and Ar-by…going to a party…take a bath, in their math…"
They went outside into the sunlight, the sounds of the girls thankfully drowned in the noise of everyone going home. Yellow school buses were in the parking lot. Kids were streaming down the steps to their parents' cars, which were lined up all around the block. There was a lot of activity.
Arby ducked a Frisbee that whooshed over his head, and glanced toward the street. "There he is again."
"Well, don't look at him," Kelly said.
"I'm not, I'm not."
"Remember what Dr. Levine said." "Jeez, Kel. I remember, okay?"
Across the street was parked the plain gray Taurus sedan that they had seen, off and on, for the past two months. Behind the wheel, pretending to read a newspaper, was that same man with the scraggly growth of beard. This bearded man had been following Dr. Levine ever since he started to teach the class at Woodside. Kelly believed that man was the reason why Dr. Levine asked her and Arby to be his assistants in the first place.
Levine had told them their job would be to help him by carrying equipment, Xeroxing class assignments, collecting homework, and routine things like that. They thought it would be a big honor to work for Dr. Levine -or anyway, interesting to work for an actual professional scientist -so they had agreed to do it.
But it turned out there never was anything to be done for the class; Dr. Levine did all that himself Instead, he sent them on lots of little errands. And he had told them to be careful to avoid this bearded man ill the car. That wasn't hard; the man never paid any attention to them, because they were kids,
Dr. Levine had explained the bearded man was following him because of something to do with his arrest, but Kelly didn't believe that. Her own mother had been arrested twice for drunk driving, and there was never anybody following her. So Kelly didn't know why this man was following Levine, but clearly Levine was doing some secret research and he didn't want anybody to find out about it. She knew one thing - Dr. Levine didn't care much about this class he was reaching. He usually gave the lecture off the top of his head. Other times he would walk in the front door of the school, hand them a taped lecture, and walk out the back. They never knew where he went, on those days.
The errands he sent them on were mysterious, too. Once they went to Stanford and picked up five small squares of plastic from a professor there. The plastic was light, and sort of foamy. Another time they went downtown to an electronics store and picked up a triangular device that the man behind the counter gave them very nervously, as if it might be illegal or something. Another time they picked up a metal tube that looked like it contained cigars. They couldn't help opening it, but they were uneasy to find four sealed plastic ampoules of straw-colored liquid. The ampoules were marked EXTREME DANGER! LETHAL TOXICITY! and had the three-bladed international symbol for biohazard.
But mostly, their assignments were mundane. He often sent them to libraries at Stanford to Xerox papers on all sorts of subjects: Japanese sword-making, X-ray crystallography, Mexican vampire bats, Central American volcanoes, oceanic currents of El Nino, the mating behavior of mountain sheep, sea-cucumber toxicity, flying buttresses of Gothic cathedrals…
Dr. Levine never explained why he was interested in these subjects. Often he would send them back day after day, to search for more material. And then, suddenly, he would drop the subject, and never refer to it again. And they would be on to something else.
Of course, they could figure some of it out. A lot of the questions had to do with the vehicles that Dr. Thorne was building for Dr. Levine's expedition. But most of the time, the subjects were completely mysterious.
Occasionally, Kelly wondered what the bearded man would make of all this. She wondered whether he knew something they did not. But actually, the bearded man seemed kind of lazy. He never seemed to figure out that Kelly and Arby were doing errands for Dr. Levine.
Right now, the bearded man glanced over at the entrance to the school, ignoring them. They walked to the end of the street, and sat on the bench to wait for the bus.
T
he baby snow leopard spit the bottle out, and rolled over onto its back, paws in the air. It made a soft mewing sound.
"She wants to be petted," Elizabeth Gelman said.
Malcolm reached out his hand, to stroke the belly. The cub spun around, and sunk its tiny teeth into his fingers. Malcolm yelled.
"She does that, sometimes," Gelman said. "Dorje! Bad girl! Is that any way to treat our distinguished visitor?" She reached out, took Malcolm's hand. "It didn't break the skin, but we should clean it anyway." They were in the white research laboratory of the San Francisco Zoo, at three o'clock in the afternoon. Elizabeth Gelman, the youthful head of research, was supposed to report on her findings, but they had to delay for the afternoon feeding in the nursery. Malcolm had watched them feed a baby gorilla, which spit up like a human baby, and a koala, and then the very cute snow-leopard cub.
"Sorry about that," Gelman said. She took him to a side basin, and soaped his hand. "But I thought it was better that you come here now, when the regular staff is all at the weekly conference."
"Why is that?"
"Because there's a lot of interest in the material you gave us, Ian. A lot." She dried his hand with a towel, inspected it again. "I think you'll survive."
"What have you found?" Malcolm said to her.
"You have to admit, it is very provocative. By the way, is it from Costa Rica?"
Keeping his voice neutral, Malcolm said, "Why do you say that?"
"Because there are all these rumors about unknown animals showing up in Costa Rica. And this is definitely an unknown animal, Ian."
She led him out of the nursery, and into a small conference room He dropped into a chair, resting his cane on the table. She lowered the lights, and clicked on a slide protector. "Okay. Here's a close-up of your original material, before we be an our examination. As you see, it consists of a fragment of animal tissue in a state of very advanced necrosis. The tissue measures four centimeters by six centimeters. Attached to it is a green plastic tag, measuring two centimeters square. Tissue cut by a knife, but not a very sharp one."
Malcolm nodded.
"What'd you use, Ian, your pocketknife?" "Something like that."
"All right. Let's deal with the tissue sample first." The slide changed; Malcolm saw a microscopic view. "This is a gross histologic section through the superficial epidermis. Those patchy, ragged gaps are where the postmortem necrotic change has eroded the skin surface. But what is interesting is the arrangement of epidermal cells. You'll notice the density of chromatophores, or pigment-bearing cells. In the cut section you see the difference between melanophores here, and allophores, here. The overall pattern is suggestive of a lacerta or amblythynchtis."
"You mean a lizard?" Malcolm said.
"Yes," she said. "It looks like a lizard-though the Picture is not entirely consistent." She tapped the left side of the screen. "You see this one cell here, which has this slight rim, in section? We believe that's muscle. The chromatophore could open and close. Meaning that this animal could change color, like a chameleon. And over here you see this large oval shape, with a pale center? That's the pore of a femoral scent gland. There is a waxy substance in the center which we are still analyzing. But our presumption is that this animal was male, since only male lizards have femoral glands."
"I see," Malcolm said.
She changed the slide, Malcolm saw what looked like a close-up of a sponge. "Going deeper. Here we see the Structure of the subcutaneous layers. Highly distorted, because of gas bubbles from the clostridia infection that bloated the animal. But you can get a sense of the vessels - see one here - and another here - which are surrounded by smooth muscle fibers. This is not characteristic of lizards, In fact, the whole appearance of this slide is wrong for lizards, or reptiles of any sort."
"You mean it looks warm-blooded."
"Right," Gelman said. "Not really mammalian, but perhaps avian. This could be, oh, I don't know, a dead pelican. Something like that."
"Uh-huh."
"Except no pelican has a skin like that."
"I see," Malcolm said.
"And there s no feathers."
"Uh-huh."
"Now," Gelman said, "we were able to extract a minute quantity of blood from the intra-arterial spaces. Not much, but enough to conduct a microscopic examination. Here it is."
The slide changed again. He saw a jumble of cells, mostly red cells, and an occasional misshapen white cell. It was confusing to look at.
"This isn't my area, Elizabeth," he said.
"Well, I'll just give you the highlights," she said. "First of all, nucleated red cells. That's characteristic of birds, not mammals. Second, rather atypical hemoglobin, differing in several base pairs from other lizards. Third, aberrant white-cell structure. We don't have enough material to make a determination, but we suspect this animal has a highly unusual immune system.
"Whatever that means," Malcolm said, with a shrug.
"We don't know, and the sample doesn't give us enough to find out. By the way, can you get more?"
"I might be able to," he said.
"Where, from Site B?"
Malcolm looked puzzled. "Site B?"
"Well, that's what's embossed on the tag." She changed the slide. "I must say, Ian, this tag is very interesting. Here at the zoo, we tag animals all the time, and we're familiar with all the ordinary commercial brands sold around the world. Nobody's seen this tag before. Here it is, magnified ten times. The actual object is roughly the size of your thumbnail. Uniform plastic outer surface, attaches to the animal by a Teflon coated, stainless-steel clip on the other side. It's a rather small clip, of the kind used to tag infants. The animal you saw was adult?"
"Presumably."
"So the tag was probably in place for a while, ever since the animal was young," Gelman said. "Which makes sense, considering the degree of weathering. You'll notice the pitting on the surface. That's very Unusual. This plastic is Duralon, the stuff they use to make football helmets. It's extremely tough, and this pitting can't have occurred through simple wear."
"Then what?"
"It's almost certainly a chemical reaction, such as exposure to acid, perhaps in aerosol form."
"Like volcanic fumes?" Malcolm said.
"That could do it, particularly in view of what else we've learned. You'll notice that the tag is rather thick - actually, it's nine millimeters across. And it's hollow."
"Hollow?" Malcolm said, frowning.
"Yes. It contains an inner cavity. We didn't want to open it, so we X- rayed it. Here." The slide changed. Malcolm saw a jumble of white lines and boxes, inside the tag.
"There appears to be substantial corrosion, again perhaps from acid fumes. But there's no question what this once was. It's a radio tag, Ian. Which means that this unusual animal, this warm-blooded lizard or whatever it was, was tagged and raised by somebody from birth. And that's the part that's got people around here upset. Somebody's raising these things. Do you know how that happened?"
"I haven't the faintest idea," Malcolm said.
Elizabeth Gelman sighed. "You're a lying son of a bitch."
He held out his hand. "May I have my sample back?"
She said, "Ian. After all I've done for you."
"The sample?"
"I think you owe me an explanation."
"And I promise, you'll have one. In about two weeks. I'll buy dinner."
She tossed a silver-foil package on the table. He picked it up, and slipped it in his pocket. "Thanks, Liz." He got up to go, "I hate to run, but I've got to make a call right away."
He started for the door, and she said, "By the way, how did it die, Ian? This animal."
He paused. "Why do you ask?"
"Because, when we teased up the skin cells, we found a few foreign cells under the outer epidermal layer. Cells belonging to another animal."
"Meaning what?"
"Well, it's the typical picture you see when two lizards fight. They rub against each other. Cells get pushed under the superficial layer."
"Yes," he said. "There were signs of a fight on the carcass. The annimal had been wounded."
"And you should also know there were signs of chronic vasoconstriction in the arterial vessels. This animal was under stress, Ian. And not just from the fight that wounded it. That would have disappeared in early postmortem changes. I'm talking about chronic, continuous stress. Wherever this creature lived, its environment was extremely stressful and dangerous."
"I see."
"So. How come a tagged animal has such a stressful life?"
At the entrance to the zoo, he looked around to see if he was being followed, then stopped at a pay phone and dialed Levine. The machine picked up; Levine wasn't there. Typical, Malcolm thought. Whenever you needed him he wasn't there. Probably off trying to get his Ferrari out of impound again.
Malcolm hung up, and headed toward his car.