(Fosters.com)
Article published Feb 3, 2012
All in the vibes: Lobsters react to environs, keep other creatures at bay, by shaking their shell
DURHAM — Next time you're tempted to tap your finger on the glass of some big lobster tank at the supermarket, consider that you may be stopping an unsuspecting lobster's heart.
Research conducted by Dr. Win Watson and students at the University of New Hampshire has determined how American lobsters react to the things happening around and to them and what they do to perhaps ward off predators.
"You're basically asking a lobster, 'Did you notice that?'" Watson explained. Through experimentation, he and his students found that when you expose a lobster to something novel, its heart rate changes, and can even stop for a period of time.
They placed lobsters in tanks for study both separately and with other lobsters, and even fish, to study the cardiac rhythms and responses these crustaceans give when affected by their surroundings or stressful situations.
In one experiment, researchers placed two lobsters in a tank with a divider so they didn't know the other one was there. Recording the heart rate of one, they prompted the second lobster to make a noise and noticed that the heart of the first lobster would stop.
"They can hear each other. We don't know if they care," he said.
Lobsters create this vibrational buzzing sound by vibrating the dorsal carapace, the lobsters largest part of its shell.
"I don't know if you'd call it communication yet," Watson said.
He said students had even consulted local lobstermen, who reported they had also noticed that some lobsters vibrate when you pick them up, a feeling similar to the vibration setting on a cell phone. Students then went around to different lobster pounds picking up random lobsters, noticing how they responded and bringing them back to the university lab to study.
They discovered that the same muscles a lobster uses to move their antennae are the muscles they use to vibrate by holding their antennae still instead.
"We knew how they did it, but we didn't quite know why," he said. That's when they began placing the lobsters in tanks to study what distractions or events caused them to vibrate, discovering, too, the fact that a lobsters heart would stop each time it noticed something.
Watson said that while all species of lobsters have the ability to vibrate, only about five out of every 100 actually do.
Watson and his students used accelerometers to measure the movements, vibration and motion of a lobster by attaching one to its back and recording vibrations on its shell.
Placing a cod in a tank with a lobster, they discovered that when the fish got within about a foot or two of the animal, it would make a sound causing the fish to swim away. Another interesting discovery was that the fish found the noise so aversive, it wouldn't return anywhere near the lobster, pointing to possibility that this noisemaking is intended to keep predators away.
"The more you work with animals, the more you appreciate what they do," Watson said.
His research on lobsters began in the late 1980s when people began calling the university's zoology department to ask how the creatures were faring after a hurricane had hit the area at that time. He didn't know, and there his interest in studying lobsters and figuring out how they survive living in an estuary began. He said 20 to 30 research papers later, he hadn't realized when he began that there was so little known about what he called a "ubiquitous animal."
Previously, he'd done a lot of work and study with horseshoe crabs and their workings, something he began as a graduate student.
Surrounded by a collection of lobster paraphernalia in his office, Watson has video on his computer showing some of the experiments conducted to determine how lobsters "talk" and even showing their movement as they struggle to move as the salinity in the tank water is decreased.
"There's still a lot I'm trying to figure out," he said.
One thing he knows in addition to all the research on sound and reaction, is that we shouldn't feel so bad for these animals. Even the tiniest lobster will likely start pinching when handled, something evidenced by the three-year-old crustacean Watson picked up by hand Wednesday afternoon that was only a couple inches in length.
"You do grow close to your animals, but lobsters are not very nice," he said.
To learn more about American lobsters and Watson's research with his students, visit www.win.unh.edu.
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