“Forget what you said last night about bats as territorial carnivores,” Ramirez told Joyce. “Thisis my doctoral thesis.”

“Pretty amazing, isn’t it?”

“Yeah. And you bagged it.”

“Barely.”

Ramirez glanced at her. “How’re you doing?”

“I’ve had quieter nights,” Joyce said.

Lowery exhaled impatiently.

Ramirez stopped talking. But only for a moment.“Is he a vespertilionid?”

“He is,” Joyce said. “Myotis mystacinus.”

“How much does he weigh?”

“Five hundred and sixty-six pounds, seven and one-half ounces,” Joyce replied. “A lot of that’s muscle, though not as much as you might think. There’s an extremely high percentage of fat in the lower thorax, roughly forty-six percent of its body weight.”

“That makes sense,” Ramirez said. “He’d need to burn a lot of fuel when he flies.”

“But he’d burn that up very fast,” Joyce said, “which would account for his enormous appetite and the need to shift, very quickly, from insects to other life-forms.”

“And there’s a female like it still out there.”

“Right.”

“She’s probably, what? Seventy percent as large?”

“If the normal ratios hold, yes. I couldn’t tell when I saw her. She was too far away. It’s amazing, though, Marc. We were just looking in this one’s chest. The lungs and heart are enlarged seven percent more than the bat’s overall size increase, though all the other organs are proportionately smaller.”

“Providing more oxygen and increased blood flow, less flying weight,” Ramirez suggested.

“That would be my guess.”

Ramirez slowly shook his head. “So what part of them did the radiation kick into overdrive?”

“I haven’t gotten to the microscope yet,” Joyce said, “but the database references a similar mutation among mice. In their case, probably this one as well, the mutation was centered in the muscle. Radiation affected the gene that encodes myostatin-”

“Right,” Ramirez said. “So the growth-regulating protein shut down, growth continued unchecked outside the womb, and in just one generation you end up with Mothra.”

“Exactly.”

Ramirez thought for a moment. “How old is this bat?”

“About eight years.”

“Long past the age when it could have sired pups.”

“Right, and I know exactly where you’re going with that. I’ve been thinking the same thing. Increased musculature usually leads to reduced fertility, just as it does with heavy-duty human weightlifters. So when an animal like thisdoes become pregnant-”

“Its mate does everything it possibly can to ensure the safety of the offspring,” Ramirez said. “It searches for a place where there’s enough water, food, shelter, warmth, and privacy to suit the mother and child. It prepares a nest. Then it goes and gets her.”

“Or given the infestation we saw last night, she or he summons an escort,” Joyce said.

Lowery shook his head. “That kind of call-pattern communication among bats would be unprecedented, and I don’t see how radiation would affect that.”

“Not directly,” Joyce said, “as in increased intelligence. But we have no way of knowing what effect a larger larynx and a lower vocal range would have on a colony.”

“You haven’t done the larynx yet?” Ramirez asked.

Joyce shook her head. “The pest control people wanted the mechanics of the bat itself first. What it’s capable of, what its weaknesses might be in case they have to-”

There were pops in the distance. Joyce stopped cutting.

“What’s the matter?” Lowery asked.

“That sounded like gunfire.”

The others were silent. The sound came again; there were three muffled reports.

“That could be a car,” Lowery said, “or one of those people who bang on plastic containers in the street-”

“I know guns,” Joyce said. “That was a rifle.”

The woman put down the scalpel, took off her mask, and walked to the door. Before she reached it there was a crash that rattled the building. The frosted glass wobbled in the door, and there was a deep creaking sound from the other side of the back wall.

“Maybe it’s construction,” Heidi said. “Aren’t they building a new planetarium over on the north side of the building?”

Joyce opened the door and stuck her head out. The corridor was quiet. She listened. The creaking came again, from down the hall. There were shouts in the distance.

Joyce jumped when Lowery’s phone beeped. Since she was closest to the desk she turned and answered it.

“Professor Low-”

“This is Rebecca Oliver at security!” a woman shouted on the other end. “They’re all over!”

“What? Who is?”

“Thebats! They’re all over the lower level!” she shouted. “And another big one! It’s trying to get-”

The line went dead. Joyce looked over at the others. Her eyes shifted to the big bat.

“Shit,” she said.

“What’s wrong?” Ramirez asked.

“The bats are here,” Joyce said. “Little ones and a big one. And the phone just died.”

Joyce stood staring down at the desk. Bats had a very highly developed sense of smell, which enabled them to identify bats of the same species. This was especially true during courtship and mating. It became even more intense in expectant bats, since it enables females who might have difficulty flying to follow males to rich food sources.

“She’s here,” Joyce droned. “The female bat. She followed the scent of her mate.”

“But she went undergroundmiles from here!” Lowery said as he tore off his mask.

“Right. And she tracked him.”

“Yeah,” Ramirez said, “but that’s not the end of the love story, is it?”

Joyce looked at him. “What do you mean?”

“What if the lady doesn’t know her big ugly’s dead? She’s not going to take that well at all.”

Joyce agreed. She turned to the dead bat. It had taken six men to hoist it onto the table. There was no way they could move it down the hall, put it in the cryogenic freezer, and try to keep it from the female.

A loud series of groans and snaps echoed up through the floor. It sounded like a car wreck that kept on going. The building shuddered again and the lights snapped off.

“Passengers, I think we better get to the lifeboats,” Ramirez said.

The room shook again as though it had been punched hard. Jars fell over and stuffed bats dropped from their perches. There was a muted crash right outside the wall on the other side of the laboratory, behind the sink.

“What’s back there?” Ramirez asked.

“The elevator,” Lowery said.

“The subway stops directly under the museum,” Joyce thought aloud. “The bat goes from there to the elevator shaft to here.” She wished she had the Magnum Gentry had given her back in New Paltz.

There was a sound like a whip on the other side of the wall.

Ramirez grabbed Joyce’s forearm and tugged her toward the door. “I say we give the lovebirds some privacy.”

Heidi and Professor Lowery had already walked past her. They opened the door and stopped.

“God!” Heidi screamed.

Hundreds of bats were coming down the corridor. Lowery reached past her and slammed the door. The bats crashed against the frosted glass, fluttering wildly on the other side.

Lowery went to the desk and snatched up the phone. It was dead. He threw it down. “All right, think! What have we got in here to protect ourselves?”

Joyce’s eyes drifted to the wings of the dead bat.

“Ultrasonic sound can disorient it, intense cold,” Lowery thought aloud. “Come on, Nannie-think!”

She was thinking, but nothing was coming. She’d seen those two large claws in action.

The wall over the sink cracked. Plaster fell in thick chunks.

The door was rattling violently, and Joyce saw a tiny muzzle squeezing under the bottom.

She pulled off her lab coat and ran to jam it against the base of the door. While she did, Marc looked around. He disconnected the receiver from the phone and knelt next to Joyce. He smacked the creature on the head.