Robert Bakker - RAPTOR RED

Raptor Red’s mind is on automatic-alert mode. She can’t sleep. Her sister is curled up in a temporary nest they made just before dusk. It’s two o’clock in the morning.

Sssnnnrrhht! Raptor Red flinches a tiny bit as her sister snores loudly, Tlssssshh.' The pair of eyes and bubble-blowing nose disappear under the pond water.

Raptor Red is disappointed - she’s still curious about that little dark head. She’s been watching it for an hour. Raptor Red is a late-night Utahmptor. She was born that way. She falls asleep at sundown but wakes up at midnight. It’s genetic, a trait she inherited from her father. Her sister is an early riser. She’s fully alert hours before dawn, but she falls asleep two hours after dusk and snores till dawn. Also genetic.

Siblings differ in their wake-sleep schedules, and evolutionary forces can work on this diversity. A diverse range of genetically fixed behaviors in a brood can ensure that at least some of the youngsters will survive to adulthood, no matter what sort of environmental challenges are thrown at them. A late-night gene may help survival when prey abundance shifts and the only vulnerable victims are herbivores who can be stalked after dusk. An early-riser gene could give just the opposite advantage -the ability to hunt before sunrise.

Raptor Red knows nothing about evolutionary theory. But she does know that her sister snores. She glares at her sister’s sleeping but noisiferous form. Just as her sister inhales in preparation for another snorting-wheezing-honk, Raptor Red reaches out with her left foot and pushes hard.

Fwwump - ooooph! Her sister rolls onto her side, exhales heavily, stays asleep, and then begins a new cycle of snores, far quieter this time.

Raptor Red goes back to watching for the head in the pond.

Just an inch below the water, the head is listening. A wide oval eardrum has been vibrating with each raptor snore. Each ssnnrrhht! has sent high-energy, low-frequency sound waves into the water. Some of the sound energy reflects off the water’s surface, but some penetrates, generating pulses of waterborne sound. The big eardrum is designed for just such low-frequency sound. It’s a turtle’s ear, and it belongs to a Trinitichelys, the Turtle of the Trinity River.

This Trinity Turtle is a female, only twelve years old and five pounds in weight. This year is the first year she has mated. Her biological clock went into alarm mode during the night. It’s time to try the most dangerous thing her genetically programmed lifestyle demands: It’s time to come ashore and lay eggs-

No two minds are more different than the raptor’s and the turtle’s. The raptor is a bundle of spunky inquisitiveness. She wants to find out about each and every animal in her world. She sniffs strange objects and pokes her snout down holes. She goes out of her way to investigate any strange and new sight. Her mind demands new stimuli, new mysteries to solve.

The turtle lives a life of comfortable monotony that would bore Raptor Red to death. Walking and swimming slowly over the pond bottom, picking up pieces of soft vegetation and an occasional hunk of dead fish. Crawling out onto a half-submerged log and letting the sun warm her turtle belly, assisting in digestion. For every ten degrees Celsius that the turtle guts warm up, the speed of the digestive process doubles. She crawls back into the pond late in the afternoon.

Every day the same routine, every day the exact same hundred square yards of pond bottom. Nothing unexpected, nothing exciting. The turtle’s body is undemanding. Her internal metabolic furnace needs only one-twentieth as much food per day as a dinosaur of the same size.

And so she is content to make do with a brain that is tiny and tubular, a brain that lacks the restless curiosity of raptors.

The Trinity Turtle would be scared into her shell and never come out if she had to deal with the range of stimuli Raptor Red experiences every day.

Pip. With a faint sound, the turtle pops her head above the surface again. The alarming sound of raptor snoring has stopped. Raptor Red creeps forward toward the water to get a better look. Her feet make a rustling noise against the dry ferns. Raptor Red freezes, but she doesn’t have to. Turtle ears can’t pick up soft, high frequency sounds. The heavy eardrum and the large ear bone attached to it can’t transmit such vibrations.

But it is perfectly adequate for the turtle’s needs. She doesn’t have to stalk soft-stepping prey across the forest floor. She doesn’t have to listen carefully for subtle variations in the calls of her mate and her siblings. Turtles live a noiseless life. They don’t communicate audibly with relatives, and the Trinity Turtle, like most of her sister species, finds food in water.

Sound is easy to detect underwater. When a crocodile snaps at a fish underwater, the sound waves pass quickly through the aqueous medium and go right through the turtle’s body with little impediment. Sound moves through the skin and then the muscle and then the brain tissue itself. So water-loving critters have an easy time hearing low-frequency sounds.

So there’s no need for the Trinity Turtle to be outfitted with the delicate ear bone and complex inner ear of a raptor. The only time she feels a deep-seated anxiety about sound is that one season of the year when she must climb out of her comfortable watery home and seek a suitable sandbank to lay her eggs. Raptor Red watches the turtle head disappear. A line of ripples shows that the turtle is swimming toward shore. Raptor Red crouches down even further, her calf muscles twitching with excitement. She’s not hunting now - she and her sister filled their bellies with iguanodon meat late that afternoon. What excites Raptor Red now is finding out something new.

Inside the turtle brain is the opposite emotion -fear of the unknown. The Trinity Turtle hasn’t been out onshore since she herself hatched twelve summers ago. That was the worst day of her life. Being tiny and helpless, cracking open her shell, and •smelling a thousand unknown things. Being one of fifty struggling turtle-ettes, all scrambling out of their nest, compelled by instinct to climb up through the sand that their mother piled on top of the eggs. Then instinct shifted gears, and the baby turtles were drawn irresistibly downslope to the smell of water.

Only two baby turtles made it to the water. The Trinity Turtle saw a brother three inches away get snatched upward in the toothy jaws of a dactyl. Then two sisters climbed over the Trinity Turtle. A second later, they too were pulled to their deaths. Just as the scent of the pond water was becoming sweet and strong, the Trinity Turtle herself was pulled four feet skyward, her left hindfoot pinioned by a set of sharp teeth. Pain, the first pain she had ever felt, paralyzed her left hindquarters. Then there was a flapping of huge, white wings and a snapping sound. Two dactyls were fighting over this turtle morsel.

She was dropped into the water. The instant she felt the warm summer water engulf her body, a third instinct cut in - to swim down. With three legs flailing madly, she made a crash dive at forty-five degrees, hitting a pond-weed clump at the bottom. She kept going, burying her bruised, half-hour-old turtle body into the mud.

The baby Trinity Turtle wasted no time grieving over her lost siblings. They meant nothing to her. In the turtle brain there is an almost complete void where the emotional bond between relatives would be in a raptor. The dead sisters and brothers were mere objects in the turtle’s environment. Their sudden deaths were useful as a warning that danger was near but had no other significance.

The Trinity Turtle, like nearly all turtle species, understands and appreciates only one individual -herself. She never saw or even smelled her mother, who scooped out a nest, laid the eggs, covered the nest, and crawled back into the water, never to interact in any way with her progeny afterward. A Lay 'em and leave 'em parent.