The juveniles heard them, though not with their ears and not with their lateral lines either. In a technical sense, they didn’t “hear” them at all, though hearing was the human sense that most closely approximated what they’d done. They possessed highly specialized organs in their heads known as ampullae of Lorenzini. Like an inner ear, ampullae are composed of delicate jelly-filled pores that provide magnetic detection capabilities. Land-based animals don’t have ampullae of Lorenzini, but they are common in creatures of the sea. Mantas have the strongest ampullae of Lorenzini in the known animal kingdom. Those of their unknown cousins were a hundred times stronger.
The rays didn’t move. Hanging in the moon-speckled waters, they simply tuned. The prey were still heading toward them. This particular type of prey wasn’t part of their regular diet, but the rays could be opportunistic—or at least try to be. The rays had already attempted to hunt this prey on several occasions and failed every time. But they’d learned lessons. They were concerned about the prey’s sonars. The juveniles themselves possessed sonar, sound navigation, and radar, but that of the approaching prey was far stronger. In its crudest form, sonar is an echo-location system in which a sound is emitted and its reflection, or echo, is analyzed. The approaching species used sonar by emitting a series of high-frequency clicks, commonly in the 200,000-hertz range. When these “clicks” met a fish, much like an X-ray, they passed through body tissues but reflected back against bone. But unlike the picture from a doctor’s office, these particular X-rays provided an intimate view of three entire miles of open ocean.
But still, as strong as the approaching prey’s sonars were, the rays’ ampullae of Lorenzini were even stronger. Their ampullae had a range of five miles and could detect the electrical activity in every one of the approaching animals’ muscles: front and rear torsos, necks, fins—even their hearts. Indeed, from five miles away, the juvenile rays had detected the prey’s individual heartbeats, more than fifty of them.
The rays knew the prey’s sonars would soon pick them up as well, but the prey’s sonars could be fooled. If a small pack of rays swam in a very particular way, they could effectively simulate another predator that the prey would attempt to evade. But in evading what they’d think was a single large predator, they’d actually be swimming toward thousands of smaller ones. A group of juveniles began moving.
FIFTY BOTTLENOSE dolphins zoomed out of the sea, their elegant gray bodies glistening in the pale moonlight. The mammals hung in the air for a brief moment, arching slightly, then knifed back in. A few miles offshore and moving at nearly twenty-five miles per hour, the dolphins were in the midst of a southern migration.
At the front of the herd, the leader was much larger than the rest— a twelve-footer weighing nearly 950 pounds. The animal had been studying the ocean ahead since the beginning of their migration, and until this point, its sonar had detected very little, just schools of tiny fish. But suddenly it picked up something else. The reading was foggy and unclear, but somewhere in the distance was a large creature. Made of cartilage, the creature appeared to be a shark, swimming from the west. The leader changed direction slightly, and like a flock of birds, the other dolphins followed.
They swam for nearly half a minute when the leader picked up something else: an unmoving mass spread out over a square mile. Again the reading was unclear, but the leader’s sonar indicated it had to be a kelp forest. Dolphins often swim through kelp forests to evade sharks, and this school intended to do the same.
They swam straight for it. What they thought was a kelp forest was a little more than a mile away.
CHAPTER 21
THE DOLPHINS had reacted as hoped.
Most of the rays still didn’t move, however. They just floated, luring the mammals closer. They knew that if the dolphins didn’t change course soon, their fates would be sealed.
THE DOLPHINS didn’t change course. They knew instinctively that something was “off” in the ocean ahead, but they didn’t know what. As they knifed in and out of the sea, the leader’s sonar continued producing unusual readings. It now indicated the kelp forest ahead might not be kelp after all, but something else, something indeterminate. The big dolphin didn’t have time to analyze it. The large cartilaginous creature from the west was still swimming toward them, and now so was a second creature, from the east.
To escape both, the dolphins had to swim right into the middle of the forest. Either that or turn around. They didn’t turn around.
THE BLACK eyes watched them. A single ray too far from the herd to participate in the hunt floated listlessly just below the surface as the dolphins leaped out. Through the shimmering water, it watched them, a sight to behold, their silhouettes flying through the night air beneath the moon. The predator saw none of their beauty. It saw food.
THE LEADER’S sonar readjusted again. Now there were four large cartilaginous animals. One to the east. One to the west. And two directly behind them.
The big mammal now knew that the mass in front of them wasn’t kelp at all. But whatever it was, it wasn’t exactly in front of them either. Not entirely. Somehow, it had moved and changed shape. It was now on their sides.
And even behind them.
THE RAYS quickened their pace. They had drifted into position earlier to avoid detection, but now they were swimming as fast as they could, approaching from every angle.
THE DOLPHINS halted.
Floating ten feet below the surface, they tuned carefully. Something had surrounded them, apparently a vast group of animals. At first, the dolphins had determined they were sharks, but sharks moved much faster and were shaped differently. These were winged creatures.
The mammals fanned their tails, rising toward the shimmering surface until their heads poked out. They still couldn’t see the rays, but their sonars reconfirmed that they were coming. And also that they had teeth. Very large teeth.
Suddenly the dolphins knew what was happening. They were being hunted.
Smart as they are, dolphins are not courageous animals. They scare easily and often lose their ability to behave rationally when threatened. Floating at the surface, a few twitched ever so slightly. Then their twitches grew larger, turning into jerks. Then the jerks turned into full-torso shakes. Then one of them cried, a single high-pitched squeal that echoed over the watery plane. Then a few more cried. Then they all cried. Suddenly the entire herd was shrieking and shaking wildly. The attack hadn’t even begun, and the once-graceful, once-intelligent animals were already reduced to a mindless, terrified mass, sheep before the slaughter.
Then a powerful, piercing scream rang out above all the others. It was the leader. Unlike the others, it hadn’t moved and hadn’t made a sound. Its strong, 950-pound body was still pointed forward, its head out. The others went silent and swam next to it, forming a straight line.
They slowly submerged to ten feet. A hanging wall of gray, they just read the signals surrounding them. They still couldn’t see the rays but knew the winged creatures were moving closer. They’d never get close enough.
The gray wall moved. Slowly at first, as the dolphins searched the waters in every direction. They saw no fish of any kind, just twisted shards of moonlight. They picked up speed very quickly and within moments were streaking through the seas.
Continuing, they looked up and, for the first time, saw two of their hunters a pool length away near the surface, winged silhouettes slowly flapping toward them.