The long-lived clam and its untimely death

Longevity may not be the first thing that comes to mind when you think of clams but some of the squishy creatures can live for centuries — if we let them.

When we think of clams, most of us probably think of food. From New England to India, people love to eat clams. But if the mollusks manage to evade predators like us, they can actually live to be quite old. To the tune of half a millennium.

But how can we even tell how old a clam is? Conveniently, they have growth lines. Much like tree-rings, the many fine lines on their shells denote their age, with one line representing one year.

The record holder (as far as we know) is the ocean quahog (Arctica islandica). These mollusks are quite common in the North Atlantic where they are harvested commercially. But one particular creature, which was later nick-named "Ming," managed to elude "harvesting" for centuries.

But in 2006, Ming's luck ran out. A group of researchers pulled her out of the ocean off the coast of Iceland. Initially thought to be an impressive 405 years old, scientists later revised their assessment to a grand 507. By that reckoning, when Ming first saw the light of day, the Americas had just been discovered, Martin Luther was only 16 years old and yes, the Ming-Dynasty ruled China.

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Sadly, we will never know how much longer the aged clam might have lived if she had been left in her element. Before they realized what a unique specimen they had caught, the researchers froze the mollusk to preserve it - killing it in the process.


Nature and Environment

No brain? No problem!

Jellyfish have been floating around the Earth's oceans for 500 million years now - without a brain to guide them. Jellyfish use their sophisticated nervous system which immediately translates outside impulses into action. That's why this rhizostome jellyfish and its relatives don't need a brain to process information.

Nature and Environment

Medusa of the seas

Jellyfish live in the sea. But the name is misleading - they're not actually fish. They're members of the cnidaria phylum and are related to corals and anemones. They're also classified as medusozoa - with the tentacles floating around their bodies, they look a little like the Greek monster Medusa, who had living snakes instead of hair on her head.

Nature and Environment

Umbrella with tentacles

A jellyfish body contains up to 99 percent water. Human bodies only contain around 63 percent water. A big part of the jellyfish is its umbrella-shaped bell. Attached to that is the manubrium, through which the animal takes up nutrients, and hundreds of tentacles. With some jellyfish, the tentacles can be a couple of meters long. The animals use them to feel their way around and to hunt prey.

Nature and Environment

Giant jellyfish

Most jellyfish are white or transparent. There are also some exceptional jellyfish species out there, though. The Asian Nomura's jellyfish isn't especially colorful, but it's huge: it has a diameter of up to two meters (6.5 feet) and can weigh more than 200 kilograms (440 pounds).

Nature and Environment

Follow the current

Scientists consider jellyfish plankton because they're swept along by the current of the sea. The jellyfish isn't great at getting anywhere by itself. It propels itself forward by constricting and relaxing its bell, achieving speeds of up to 10 kilometers per hour (6 mph). Even bugs walk faster.

Nature and Environment

Pretty and poisonous

Jellyfish might look graceful floating through water like squishy goasts, but some of them have extremely dangerous tentacles - like this lion's mane jellyfish. Their tentacles are covered in nematocysts. The animal injects the stinging cells into its prey and kills them with the toxic injection. Plankton, algae, small crabs and fish larvae are all on the menu.

Nature and Environment

Burns like fire

For humans, encounters with the lion's mane jellyfish are very painful: after a sting, our skin burns and develops red welts. At least there's no lethal danger - which can't be said for encounters with the box jellyfish, or sea wasp. This species is at home along the northern and eastern coasts of Australia and in the western Pacific. Its toxin is among the strongest in the animal kingdom.

Nature and Environment

Colorful special effects

What else can jellyfish do? Tons of things! Pelagia noctiluca for example starts glowing as soon as its triggered mechanically, for example by water turbulence. This ability to create light, either alone or with the help of bacteria, is called bioluminescence. Incredible, isn't it?

Nature and Environment

Sophisticated life cycle

The sexual and asexual reproduction of jellyfish alternates from generation to generation. When jellyfish have produced sexual cells, these cells merge and create a larva type that attaches itself to the seafloor. A polyp emerges from this, and later several new jellyfish emerge from the polyp.

Nature and Environment

The sleepyhead of the sea

Jellyfish have no brain and no heart. But they do sleep. Surprised? Researchers at the California Institute of Technology have found that the upside-down jellyfish, Cassiopeia - which spends most of its time on the seabed - shows signs of sleep at night. How is that? Well, their pulse drops when they nap. And when they are disturbed, it takes them a while to wake up - just as with humans.

Nature and Environment

Jellyfish carpaccio

Beach towns often have to deal with jellyfish invasions. Bioligists believe this is due to overfishing and the decline of sea turtles and jellyfish-eating fish. But the squishy sea-dweller is also gaining popularity as a delicacy on restaurant tables. It has no natural aroma, which makes it the perfect flavor carrier.

Nature and Environment

Stranded

If you find a sad blob like this on the beach, it's most likely a jellyfish out of its natural habitat. If you want to do a good deed, grab some gloves for protection and deliver the animal back into the sea. Don't touch it with your bare hands, don't step on it and don't toss it onto your unsuspecting girlfriend while she's sunbathing.