The Secret Life of Lobsters (7 page)

In the preceding days the scientists had coined a nomenclature to describe behaviors they were observing for the first time, including “substrate jab,” “dig display,” and “entrance ceremony.” What the female did next could be termed only one thing: “knighting.” The female stepped up to the male and laid her claws on his head. He stood still, poised on tiptoe, fanning his swimmerets madly. She removed her claws and stepped back while he felt her with his antennae. She knighted him again several times. A few minutes later she fell over on her side, unzipped the back of her shell, and began to wiggle.

 

“How about a game of backgammon?” Bruce Fernald asked.

Barb Shirey had been taking an afternoon stroll along the roads of Little Cranberry Island when she passed the house where Bruce lived with his brother Mark. Bruce had poked his head out the door and called out his invitation.

Behind Barb the road sloped down to the town field, the grass dry and golden in the late-afternoon sun. Barb remembered the way it had been on the Fourth of July, green and
bustling with the chatter of picnickers and the yells of a softball game. At summer's end the vacationers had boarded up their cottages and departed, and the only sound now was the rhythmic chirp of crickets. Past the edge of the field, the wharves reached into the harbor, and beyond them the lobster boats hung on their moorings. Bruce's sexy jet-black boat, the
Stormy Gale
, lay in the center of the pack. A chill snaked through the air, and Barb shivered.

“You know what?” Barb said. “I'd
love
to play a game of backgammon.”

Hunched over the backgammon board in the toasty living room, basking in Bruce's grin and his naughty fisherman's jokes, Barb thought she could get used to winter on Little Cranberry Island. By the third game Barb was feeling very comfortable. That's when Bruce decided to let her in on a secret.

“You know,” Bruce said, “upstairs I have black satin sheets on my bed.”

At sea, Bruce had matured into a talented fisherman. He caught a lot of lobsters, and one day he'd even caught an eight-point buck, lassoing the deer right from his boat while the animal was swimming. He'd pulled it in with his hydraulic trap hauler. Now, with his characteristic confidence, Bruce had cast his line for Barb. She was mortified.

“Um, no thanks, I'm not interested.”

“Aw, hell,” Bruce said, leaning back on the sofa and expelling a heavy sigh. “I shouldn't have said that. Sometimes a guy just doesn't know what to say.”

Bruce's words came as a relief, and suddenly the room felt cozier. She couldn't explain why, but Barb felt herself begin to melt.

“Well, how about another game?” Barb offered.

 

Meanwhile in Woods Hole, Jelle Atema had been assuming that the strongest males would pursue and select the most attractive females, and the weaker males would find the less
attractive females. But his experiments had shown almost the reverse. The strongest male had simply waited at home. A female had come to his shelter and selected him. The weaker males weren't selected at all.

Jelle now realized that his theory of the female sex pheromone had been backward. Indeed, if the lobsters' behavior in the tanks reflected their actions in the wild, Jelle had stumbled onto something new. What little research had been conducted on the subject so far suggested that in crustacean mating, the males usually took the active role in selecting mates, while the females were passive. In the confines of the thirty-gallon tanks Jelle had used initially, male lobsters had approached molting females. But in the more natural setting of the fifteen-hundred-gallon tanks, the females initiated the approach. Jelle had apparently found a species where the females did the choosing.

A female's sex pheromone was still required for mating to occur, as Jelle's earlier experiments in the small tanks at his old lab had shown. In the big tanks, the dominant males had frequently fanned their swimmerets during encounters with their prospective mate. Fanning created a water current through the shelter, drawing the female's scent in through the front entrance and suffusing the shelter with her smell. As far as Jelle could tell, not only was the female doing the choosing, but by exuding her pheromone she was administering a sort of aphrodisiac designed to turn down the volume on the male's aggression and encourage him toward more tender pursuits. That was quite different from Jelle's original assumption—that a female used her perfume as a homing signal to attract aroused males.

A female lobster would gain obvious advantages by drugging a dominant male. She not only ensured robust genes for her offspring but also secured the best available protection for herself during her most vulnerable moment, the shedding of her shell. The male also gained advantages from this arrangement. Waiting for the female to molt required patience, but it also prevented cuckoldry. The external pouch that formed the female's seminal
receptacle was part of her shell. If she had copulated previously with another male, that male's sperm would be thrown out when the female shed, as if she'd been wearing a body suit with a built-in diaphragm. By waiting until the female molted, the male ensured that the offspring would be his.

After copulation the female huddled in a corner of the shelter while her new shell hardened. In exchange, she left her old shell as a postcoital snack for the male. He began nibbling it just a few minutes after dismounting—the lobster equivalent, perhaps, of edible underwear. By evening the female had sufficiently recovered to get up and eat some of her old shell herself. But the male, feeling satisfied, was now keen on cleaning up. He gathered the remaining pieces of her discarded exoskeleton and tossed them in a heap outside the door. The other lobsters in the tank sidled up to the pile like nervous looters and ran off with whatever piece of her shell they could carry.

Over the next few days the dominant male began to leave the shelter regularly again, resuming his bullying and foraging for food. At first the female stayed indoors, her shell still thin as paper. When the male brought food back she would occasionally snatch a chunk for herself. The nourishment strengthened her and she tried to exit the shelter, but the male jealously blocked her way and boxed her claws. One night while he was out, she left.

She came back before morning, and they rested side by side during the day. But they went their separate ways again that night. A few days later the female, her shell growing rigid, was resting inside the shelter when the male returned with food. This time when she tried to help herself he snapped at her. Soon afterward she left and never returned.

In both of Jelle's two tanks, the pairing of the dominant couple had lasted all of two weeks. Things returned to normal, the dominant male continuing his bullying and occupying the best shelter by himself. The females loitered nearby and the subordinate males languished in their ghetto at the other end.

But in one of the tanks the drama took a macabre twist. It came time for the dominant male to shed his own shell. He discontinued his bullying and sequestered himself in his shelter to molt. Wiggling out of his spent exoskeleton, he pumped himself up to an even more impressive size. His new shell was so soft he could hardly stand.

The next time the researchers checked the tank they couldn't find him. Bits of his old shell littered the shelter. Closer examination revealed remnants of body parts scattered throughout the tank. The other lobsters sat in their crannies, stone-faced. They had, it appeared, exacted their revenge.

In the other tank, where the dominant male still reigned in his large shelter, something even more surprising happened. A few weeks after the female moved out, the scientists found standing at the dominant's door a new female, fresh and ready to molt.

 

It was the best round of backgammon Barb had ever played. Despite her obvious talents, Bruce kept Barb working aboard the
Stormy Gale
without offering her a job. She hefted gear, baited bags, plugged claws, and stomached the sea as well as any man. She cracked jokes, played tricks, and exuded energy. Sometimes she even gave Bruce a peck on the cheek to break up the workday. No sternman had ever done that to him before.

At the end of another day at sea Bruce set a course for the island. He crossed his legs, leaned sideways against the bulkhead, and draped his hand over the steering wheel in the lobsterman's classic posture of repose. As he squinted over his shoulder at the water ahead, Barb admired his profile, the nose a straight-edged triangle and the chin chiseled. Her eyes fell to his powerful shoulders and then wandered across his chest. But she was annoyed with him, the sexist bastard. He still hadn't agreed to take her on for the rest of the season. She was sure it was because she was a woman.

“Oh, by the way,” Bruce said a few minutes later, “you're hired.”

Bruce turned and smiled at his new sternman. Barb pumped her fist in the air and grinned, wanting to kiss him and hit him at the same time.

A
fresh new female was waiting outside the entrance to Jelle Atema's laboratory in Woods Hole, and her name was Diane. She had just graduated from college and her passions were courtship and lobsters.

Diane Cowan had fallen in love with the American lobster after writing an English paper on the crustacean in ninth grade. Within a year she had learned to scuba dive. During summer nights on Long Island Sound, while her peers partied on the beach, Diane would slip into the black water with her mask and scuba tank and stalk lobsters on the bottom. Often she surfaced clutching a few specimens for the dinner table. Steaming them and picking them apart was both a gastronomic delight and an anatomic adventure. Diane liked eating males more than females because their claws contained more meat. To her friends who preferred tails, she explained that technically the term “tail” refers to a postanal mammalian structure, and pointed out that a lobster's anus is all the way at the end.

“So this isn't a tail,” Diane would state, dipping a morsel in melted butter. “It's an abdomen.”

When she graduated from high school in 1978, Diane's friends signed her yearbook “To the Lobster Lady.” Her first career move was to talk her way aboard a lobster boat in Provincetown at the tip of Cape Cod.

Diane went to college at the State University of New York at Binghamton. The campus had advantages, including a fabulous professor of animal behavior, but also disadvantages,
including the lack of a nearby ocean. While Diane jumped through the hoops of undergraduate life, she amassed a personal collection of newspaper and magazine clippings on lobsters, some of which referred to Jelle Atema's research in Woods Hole.

By her senior year Diane was leading lab sections in the comparative anatomy of fishes, amphibians, and reptiles. When she was assigned an independent research project for an animal behavior class, she decided to study courtship communication. Lacking a local supply of lobsters, she instead chose the green anole, a color-changing lizard often called the American chameleon. Like lobsters, male anoles compete for dominance in order to attract females. They bob their heads up and down, do push-ups, puff up their necks, and pose sideways to accentuate their size. The project required Diane to construct her own anole cages from wire and wood, but her lizards were forever escaping. Usually they were returned the next day by classmates working in distant parts of the building.

One day when Diane walked into her professor's office to discuss her lizards, her attention was riveted by a pair of enormous lobster claws on his desk. She pointed.

“Someday
that's
what I'm going to study,” she exclaimed.

The professor asked Diane what she knew about lobsters. He wasn't prepared for the volcano of information that erupted. Diane explained that lobsters communicated using chemicals, and that they were probably attracted to each other's pheromones, as well as to the chemicals in petroleum.

“I'm very concerned,” Diane concluded, “that lobsters will migrate toward oil spills, thinking they smell like their sex pheromones, and then all the lobsters will die.”

All college students, Diane assumed, were already on an obsessive quest similar to her own pursuit of lobsters. But her professor knew otherwise.

“I have a friend,” the professor told her, “who studies lobsters down in Woods Hole. You should write to him and go visit his lab. His name is Jelle Atema.”

With this introduction Diane sent Jelle a letter. Hoping for
a summer job, she mentioned that she happened to be traveling to Woods Hole—this was a bald-faced lie—and wondered if she could tour his facilities. In April Diane and her mother made the trip to Cape Cod. The village of Woods Hole was still quiet before the arrival of summer tourists. The picturesque main street of shingled shops was bisected by a comically small drawbridge, through which lobster boats and sailboats chugged out from Eel Pond into Vineyard Sound. From the center of town, the laboratory buildings of the Woods Hole Oceanographic Institution and the Marine Biological Laboratory radiated in a maze of cement, stone, and red brick. Along the waterfront Diane saw the Oceanographic Institution's enormous ships, bristling with cranes, antennas, and research equipment.

Jelle greeted Diane and proudly showed her his physiology room, with its Petri dishes and shelves of electronics. She tried to hide her disappointment, for the room contained no lobsters. Then Jelle led her into the concrete basement and she saw the twenty-foot tanks. It was love at first sight.

The infatuation was fleeting, for the tanks contained no lobsters. Jelle had no formal mating experiments planned that summer, and he'd already filled his roster of research assistants on other projects.

“I don't even have a desk you could use,” Jelle apologized. But seeing the look on Diane's face, he had a second thought. “If you're going to be around this summer anyway, you're welcome to clean up the tanks and play around with them.”

Diane couldn't have cared less about a desk. All she wanted was a chair—and a tank full of lobsters to watch. Diane arranged a babysitting job in Woods Hole in exchange for room and board for the summer. Her plan was to watch the children during the day and the lobsters in the evenings, when the nocturnal creatures emerged from hiding.

After returning home to gather a suitcase of clothes and her guitar, Diane moved to Woods Hole in the middle of May. Jelle was away, so she polished the glass windows of one of the tanks spotless, and at low tide took a bucket to the beach,
where she collected starfish, sea urchins, mussels, small crabs, and moss-covered rocks to populate the tank. She even set minnow traps outdoors to stock it with fish. When Jelle returned, he was impressed. A few days later he handed her a bucket rattling with seven lobsters.

“There's a lot we still don't know,” Jelle told Diane. “We don't know how females compete against each other to decide which one gets to mate with the dominant male first. All we know is that in our initial experiments, after one female moved out a new female moved in.”

Jelle guessed that skewing the gender ratio in the tank might shed light on what was happening. Of the seven lobsters he had given Diane, five were female. The remaining two were a pair of lucky males.

“Keep an eye out for signs of competition between the females,” Jelle suggested.

Before dropping the lobsters in the tank, Diane slipped a band around one claw of each animal and labeled them. She named the females F-1 through F-5 and the males M-1 and M-2, though for the purpose of taking notes she decided to use the nicknames M and MM. She equipped herself with a pen and paper and began watching the lobsters in the evenings after work.

Trouble developed quickly, but at first it wasn't inside the tank. The family that employed Diane as a live-in babysitter began asking her to work nights as well as days. Diane was adamant in her refusal—her nights were for the lobsters. So she left.

Finding a new summer residence in Woods Hole was by then impossible, so Diane tucked her suitcase and guitar in a corner of Jelle's lab and took up a nocturnal existence herself. She slept on the beach during the day, woke in the afternoon and went for a swim, then bused tables at a local restaurant until nightfall, when she would return to the lab. Alone under the red darkroom bulbs in the basement, Diane often watched the lobsters until dawn. At one point, she challenged herself to witness, in a single sitting, an entire twenty-four hours in the
life of her lobsters. Her record would be eighteen and a half before she collapsed from exhaustion. It seemed an unusual degree of dedication. But Diane had been waiting for this since ninth grade.

Jelle required only a couple of morning encounters with his bleary-eyed volunteer to recognize that her passion was badly in need of discipline. He didn't discourage her marathon sessions in front of the tank, but he taught her how to collect statistically useful data as well as impressions. Soon Diane had drawn a map of the tank and was recording a daily census of the inhabitants, noting each lobster's location every hour on the hour. When she was asleep on the beach or busing tables, one of Jelle's other assistants would take the readings for her. And twice a day at prescribed times Diane conducted what were called focal observations on each animal, quantifying its behavior using a system of standardized codes.

There was no getting around the raw violence on display. The two males, M and MM, were exactly the same size, which prolonged the contest for dominance. Diane recorded forty-six fights between them. M bested his opponent in forty-two of the encounters and finally MM had no choice but to accept subordinate status.

As in Jelle's previous experiments, a row of cinder blocks along the back wall of the tank provided places to hide. Along the front wall there were now four specially molded concrete shelters, larger than the previous ones. Each had two entrances and had been placed against the glass so Diane could see inside. M took up residence in the shelter at one end of the tank. MM bypassed the two middle shelters and occupied the shelter farthest from M, at the other end. Of the five females, one occupied each of the middle shelters and the rest made do with the cinder blocks at the back.

Every evening M would emerge from his shelter, march to the hiding place of each of the females in turn, and bully her until she fled. For good measure M always stopped by the far end of the tank and kicked MM out of hiding too. Then M would strut back to his shelter, slip inside, face the entrance, and wait.

Within days one of the females began visiting the entrance to M's lair. She courted M until he let her inside for a visit. After several visits she moved in, molted, and mated with M. A few days later she was making brief forays into the tank again, though at first she returned to M's shelter after each trip. It wasn't long before she left M's shelter for good.

Almost as soon as she was gone another female was waiting at M's door, and the routine began all over again. The new female courted M, began to visit him inside his shelter, and then moved in with him. She molted, they copulated, and then she began to come and go. After a while she, too, stopped visiting. A day after her last visit, a third female was waiting on M's doorstep.

Again, the third female courted M and moved in with him after a few days. She molted and they mated. After her shell had hardened up she began to come and go. But she was still staying with M when a fourth female snuck in and visited M in the third female's absence. The next day the third female moved out and the fourth female moved in and shed her shell, enticing M to mate a fourth time.

To Diane it looked as if the female lobsters weren't so much competing as cooperating. Yet she'd observed no indication that the females had established any sort of hierarchy to decide who went first, second, third, or fourth. Diane discussed the behavior with Jelle. Biologists had seen similar mating strategies in birds and mammals—the females taking turns so they could all mate with a particular male. There was a name for it: “serial monogamy.” The deliberate staggering of molts by a group of females, however, had never before been observed in crustaceans. The female lobsters appeared to be using serial monogamy to ensure that they all had access to the dominant male. But how, exactly, did they do it?

The question grew more complicated when Jelle and Diane discovered that lobsters occasionally bent the rules of serial monogamy. Both genders improvised alternative strategies to subvert the norms of lobster mating. For example, one female suffering from PMS barged into the dominant male's
shelter and took a chunk out of the resident female with her claw.

Another who was eager to mate dealt with her dilemma differently. This female—number six—was a newcomer to the tank. After the first two females had mated with M, Jelle and Diane had decided to replace them with fresh females to see how long M could sustain his heroics. M, who continued his tours of bullying, welcomed the new females to the tank with nightly beatings. Female six seemed to find M's advances particularly arousing. But M was already busy with two other females, as his third and fourth mates played hide-and-seek in his shelter. According to the rules of serial monogamy, female six would have to wait her turn. But she was ready to get undressed.

During M's sexual adventures MM had waited forlornly in his shelter at the other end of the tank. The introduction of fresh females turned out to be his lucky break. Female six, fed up with the maneuvering at M's end, paid a visit on MM. After a few days of courtship she moved in. Several times M stopped by and tried to interfere, but female six soon shed her shell, lay on her back, and accepted MM's thrusts.

Males could be equally flexible. For instance, MM spent less time and energy copulating than M did, which gave the subordinate male leeway to pursue other activities—like improving his physique. Perhaps emboldened by his luck with female six, about a week after she moved out MM shed his own shell and molted up to a bigger size. There was a disadvantage to this. Molting took him out of the running for at least two months, the time required for his shell to harden enough for fighting. But it gave MM a 50 percent jump in body weight that he could ultimately use to challenge M, and presumably earn himself some of the new girls. Had Diane continued to add new females to the tank, MM's strategy of outmolting the competition would probably have paid off.

In later experiments, Diane would see another subordinate male molt up and reap the benefits. This subordinate didn't directly challenge the dominant male, but the molt appeared to
have given the lobster bigger balls, as it were—he snuck into the dominant's shelter and took advantage of the resident female while the dominant was out.

In another experiment the subordinate fared even better. After he molted up to a larger size, not only had he become the new dominant when fresh females arrived, but he also convinced a brooding female to jettison a perfectly good batch of eggs so she could make new ones with him. This female had mated in the ocean before being captured, and had extruded the eggs onto her tail during her residence in the tank. But impressed with the new physique of the former subordinate, she molted and mated again with him. Once the eggs attached to her shell were discarded—they quickly died—she received sperm from the newly dominant male to fertilize a whole new batch of eggs.