Woods Hole Scientists Unlock Lobster Secrets Through Scientific Grilling
A lobster no larger than a thumbnail warily watched a slender paint brush, then reached out tentatively with a tiny claw and grasped a few bristles.
“Ahh,” said C. K. Govind, the researcher on whose rough palm the little crustacean rested. “Now we repeat.”
Gently he stroked the baby lobster with the brush, and again it grasped the bristles, with the same claw.
Within a few months, that baby claw, the one Govind was teaching the lobster to favor, should grow into a bulky, “crusher” claw that can snap open a mussel shell effortlessly.
Its other claw will be a lightning-fast, slender “seizer” claw that can snap shut on a darting fish five times faster than humans can blink their eyes.
Most people don’t usually consider a lobster’s claw, except as something to crack open during an expensive dinner.
13 Years of Study
But Govind has spent 13 years discovering why almost all lobsters have one massive crusher claw and one narrow seizer claw. And more perplexing, why the crusher is sometimes on the right and sometimes on the left.
He has discovered that between the fourth and sixth molt of a lobster’s life, the claw it uses most will become its crusher and the other its seizer. Govind has managed to control the process by stimulating the claw of his choice with a paint brush during the crucial developmental period, ensuring that that claw will become the crusher.
“In its natural environment, it’s a 50-50 chance which claw it will start to favor,” Govind said in his laboratory at the Marine Biological Laboratory at Woods Hole. “With a brush, we can pick left or right.”
Govind is not the only scientist at the Woods Hole research facility who has spent years studying the American lobsters found in abundance off Cape Cod. Laboratories there are literally crawling with the crustaceans. In tubs, tanks and pools, lobsters of all sizes and colors are prodded, monitored, mated, molted and, occasionally, eaten for dinner.
Reasons They Are Studied
“Why lobsters?” asks researcher Jella Atema. “They are the right size, they have marvelous chemical receptors, and they do have economic value.
“It’s rare for one species to be studied so thoroughly,” he said. “Usually research is scattered across different species. But here you find a lot of research centered on one animal.”
Scientists at Woods Hole over the last decade have come to understand not only how lobsters develop physically, but how they see, smell and communicate. They have studied lobster behavior as well, gaining insight into how the creatures eat, mate and die.
In the basement of one laboratory building, Diane Cowan peered into the murky water of a massive fish tank and watched intently as a pair of lobsters interacted within the confines of a crate-sized concrete shelter Cowan had made two summers ago.
“The female will molt in a day or two, and then they’ll mate,” said Cowan, a graduate student in biology at Boston University. “Somehow she’s signaled to him that she’s ready.”
Parallels With Humans
In Cowan’s eyes, the life of a lobster has some parallels to that of a human.
They have a long childhood and an awkward adolescence. They establish mating relationships through complicated signals, then carry their young for nine months. Some eventually grow into a crusty old age of many decades.
“After I set up the lobster tanks I would come in and watch them every night,” Cowan said of her early days as a graduate student in Atema’s lab. “I lived with lobsters. They’ve always fascinated me.”
What Cowan observed in her nightly vigils is that a dominant male lobster in a community will take over the best shelter available. During the warm months, all of the females in the vicinity will approach and take turns mating with him.
The females tell the male they are interested by spraying a current of chemicals in his direction. Once he allows one into the shelter, the pair will form a bond that lasts from several days to two weeks.
Female Molts
Halfway through this period, the female will shed her shell in a molt--a process adult lobsters undergo about once a year--and they will mate within 30 minutes.
“Lobsters mate like humans,” Cowan explained.
Over the next few days, the female’s shell will harden, and she will eventually leave the shelter, making room for the next female of the summer mating season.
“The arrangement has real advantages,” Cowan said. “The female lobster is protected during her molt when she is vulnerable to being eaten, and the male knows his offspring have a better chance of surviving.”
Cowan said the female lobster will keep the male’s sperm and eventually use it to fertilize her eggs within the protection of her tail. In the spring, she fans the eggs away from her body as they hatch into larva no larger than fleas.
In his laboratory in a neighboring building, Govind focused a microscope on a petri dish filled with seawater, revealing translucent lobster larva in all their glory. They are large eyed and iridescent in orange, red and green with a characteristic spike along the back and a tail like a shrimp.
Take Off Through Currents
A lobster larva will molt three times before it looks like a lobster. Then herds of the tiny creatures will swim through ocean currents, their claws stretched out and bodies streamlined.
“We call them superlobsters,” Cowan said.
The babies will molt about a dozen times in their first year of life, each time growing a little larger and a little sturdier. Sometime after their third or fourth molt, they will stop swimming and start crawling between the crevices of rocks, evading predators and hunting for little bits of food.
“Lobsters are garbage cans,” Cowan said. “They’ll eat anything--mussels, squid, fish, even other lobsters that have molted.”
After its fifth year, a lobster is big enough to mate, researchers said. (The typical lobster on a dinner plate is in its sixth or seventh year.)
Lobsters continue to molt throughout life, although the procedure becomes less frequent and more exhausting and dangerous each time.
Pulls From Shell
During a molt, the crustacean will break its shell at the base of the tail and simply pull out, leaving the shell whole. Anyone who has picked lobster meat will understand how small a lobster must shrink its claw to pull through the crevices undamaged.
For an hour or so after molting, a lobster will soak up water as it lies helpless with a new shell so thin it appears nonexistent. At this stage it is in danger of being eaten by other creatures, including fellow lobsters.
Cowan said it takes a month for a shell to completely harden and during that time most lobsters will avoid confrontations because they can easily lose claws or legs.
The limbs will grow back during the next molt, but the process is slow, and a lost claw could affect the creature’s standing in the community pecking order.
Researchers are not sure how long lobsters live, but some estimate up to 100 years. According to the Guinness Book of World Records, a 3 1/2-foot lobster weighing more than 44 pounds--roughly the size of a 6-year-old human child--was found off Nova Scotia in 1977.
In the center of Atema’s office dangles the crusher claw of a giant lobster, suspended from an invisible thread. Atema leaned back in his chair beneath it recently and considered the animal he has studied intently for 15 years.
“It has been difficult for us to imagine how a creature senses in an environment so different than our own,” Atema said. “We run into definition problems right off when you ask what is ‘taste’ or what is ‘smell.”’
A lobster has two sets of antennae--the largest arching the length of the body and able to swivel in a complete circle--that it uses to “smell” chemicals in the water. In addition, it has fine sensory hairs along its legs with which it “tastes.”
Atema’s research has shown lobster communication is sophisticated and direct. The crustaceans fan their pleopods, small fan-shaped flippers along their tails, then release chemicals from their urine into the currents of water they stir up.
Assumes Lobster Role
The researcher, a Belgium native who once studied flute with Jean Pierre Rampal, tends to talk in first-person-lobster.
“One of the wonderful things about the chemical system is that some signals you can’t control,” he said. “If I’m in a current, I will be out there for everyone to pick up on, be they prey or predator or potential mate.
“People have a fair idea of the life of a dog, how they sniff their way around,” he said. “It’s the clearest correlation for lobsters. They walk around creating currents and reading them.
“The currents are vitally important,” he continued, putting his hand on top of his head and slowly wagging his index finger. “You quietly stick out an antenna and listen to what’s out there.
“In short,” he concluded, “I’m trying to understand what it feels like to be nonhuman and living in another world.”
Although the combined years of research on lobsters at Woods Hole add up to decades, there is still a lot of mystery surrounding the crustaceans.
For the last year, Cowan and fellow graduate student Sarah Ellis have attempted to make a catheter that will catch the urine of lobsters so they can identify the chemicals used in communication.
If the scientists can begin identifying chemicals, they can begin to understand how male lobsters establish dominance, how females determine mating order among themselves, and how they communicate to the male they are about to molt.
Frequently Asked Question
The researchers said they plan to continue their experiments for another decade and to patiently answer the one question they hear constantly.
“Do you eat lobster?”
Govind says never.
Cowan does occasionally, lecturing friends over lobster dinners with claws and antenna as visual aids.
As for Atema, he smiled at the question.
Several years ago his laboratory was moved from one building to another in the dead of winter. Afraid the lobsters would not survive the shuffle, he and his colleagues started the water boiling instead. They invited the entire laboratory research community for a memorable feast that featured over 100 hefty lobsters.
“They are wonderful in so many ways,” he said.
