December 12, 2013 A Lobster Tale
The mysterious lives of lobsters have intrigued humans since their first description by Pliny in 100 AD – and for many good reasons.
With lobster names like: Hunchback locust, regal slipper, marbled mitten, velvet fan, musical furry, unicorn, buffalo blunt-horn, African spear, Arabian whip and rough Spanish; it’s not difficult to see that some 45 species of ocean dwelling lobsters with a global annual worth of $31 billion are of culinary and scientific interest.
Lobsters have inhabited oceans for over 150 million years and because their initial design was near flawless – they haven’t changed much since, though some species have grown smarter and clawless. They have, however, endured the mass extinction of 65 million years ago and survived a family feud of 30 million years ago with crabs.
Today they are restricted to salt-water neighborhoods with complex stone- and boulder- filled bottoms.
Their main predator up until 5,000 years ago was cod. About 3,000 BC humans began hunting cod particularly in Maine and once stock numbers fell in the late 1800s and again in the 1940s the American lobster, Homarus americanus, population flourished.
The Gulf of Maine boasts the densest population of lobsters on the planet.
Some beasts inhabit depths in excess of 2,000 feet, growing to an astounding size of 4 feet, weighing a whopping 44 pounds. This greenish-brown species has a vast range extending from northern Labrador, near Greenland, to North Carolina.
Its closest cousin is the bluish-black European lobster, H. gammarus, inhabiting the waters of Western Europe. They both turn red when boiled because the molecules in their shells bend into shapes that absorb the different wavelengths of light except red, which it reflects.
Both species share a recessive bright blue gene. Recently, a rare genetic mutation showed up at a New Brunswick, Canada restaurant – a stunning indigo colored lobster. Thankfully, it was sparred the boiling caldron and returned to the frigid Atlantic.
Other mutations of colors occur including yellow, white, calico and even red and every so often a half-and-half lobster with a line straight down the middle of its back.
Lobsters were designed as exceptional stone movers and excavators, creating burrows with two entrances. They are nocturnal critters.
Their eyes detect motion under very low light but cannot delineate fine details.
Instead they rely upon touch receptors on two long antennae and thousands of minute hairs on their shells, claws and legs. In addition, these hairs also act as – ears – listening to the vibrations in the water.
Lobsters possess an acute sense of smell. They sniff the water from a smaller pair of two-pronged antennae known as antennules – each containing hundreds of chemical receptors crucial for both hunting and socializing skills.
Taste receptors are located on the feet – like flies – and in the mouth.
Many species of lobsters are born with ambidextrous claws. During the first couple years of life the lobster determines which claw will be its crusher and which will be its seizure and cutter.
Lobsters have four pairs of legs that facilitate a seasonal migration of up to 20 miles annually. As the spring water temperatures begin to warm, lobsters walk from the deep mud plains to the rocky shallow shorelines.
One New Brunswick lobster jogged an astonishing 500 miles through mountainous terrain reaching Rhode Island some six months later.
In order for a lobster to grow it must shed its skin or molt. Essentially, its skin is a three-layered, padded suit of armor. The outermost layer is made up of proteins, lipids and calcium salts. Beneath are another layer of protein and a hard substance of chitin – the same compound that makes up the exoskeleton of most insects.
Temperature-sensitive glands within the lobster’s eyes control the molting process and prior to shedding, calcium within the shell is reabsorbed into the stomach and used later to grow new shells.
Within 20 minutes the lobster accomplishes a remarkable feat of pulling its old shell off, including removing it from its antennae, mouthparts, legs and claws. It must diet and lose 50 percent of the mass in its claws to perform this nimble task. Finally, it pumps its body up with water and discards the last remaining shell from its tail.
A couple days later the new shell has thickened, the lobster has increased in size by 15 percent and 50 percent in volume. During the first five years of its life it must undergo 25 molts, decreasing to twice a year and finally at maturity of 7 years, once a year.
A female urinates from bladders inside her head below antennae to attract a male partner. Once she’s selected a partner, she molts. An endearing courtship can last for a quarter of an hour. The male continuously circles and strokes the female before she stands straight up and he embraces her face to face, pushing her onto her back, locking their tails (which contain dual reproductive organs), thrusting a couple times over a period of 10 seconds before they unclasp.
Females can fertilize eggs immediately or delay them for almost a year. Birthing occurs over the coarse of a week and each night she releases thousands of young. One five-pound female can produce twenty-seven one-pound females.
Young lobsters jettison through the water like torpedoes evading sculpin and cunner predators with Cirque du Soleil acrobatics. About a week later once they touch bottom they never leave it again. Within the first five days they will swim about 25 miles.
As if the lobster life history isn’t rich enough – the design of its 13,000 mirrored, tapered boxes within each of its eyes have inspired scientists to create a new X-ray vision space telescope called Lobster-ISS for use on board the International Space Station; facilitating exploration of our galaxy and beyond.
Earth Dr Reese Halter is an award-winning broadcaster and distinguished conservation biologist. His latest book with Chris Maser is Life, The Wonder of it All
Text © by Dr Reese Halter 2013. All rights reserved.
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