Mollusks are generally characterized as having a soft body, and their exoskeletons, commonly known as shells, have evolved into countless forms, sizes, shapes, and colors—many of which wash up on shores around the globe.
Giant clams are one of the many wonders of coral reefs. They can grow up to five feet wide, weigh over 400 pounds, and live for 100 years! They power all that bulk by filter feeding microbes and particles from the water, siphoning hundreds of gallons of water per day. Like corals, they also have a symbiotic relationship with photosynthetic algae called zooxanthellae that live in the fleshy part of the clam and provide it with food.
Sadly, because they are so beautiful, people like to collect giant clam shells for aquaria and eat the meat inside. The largest giant clam in the Indo-Pacific (Tridacna gigas) was believed to be extinct in Fiji due to overharvesting—but they are being reintroduced. Read more at the Global Reef Expedition blog from the Khaled bin Sultan Living Oceans Foundation.
The clam in question is the Noble Sea Pen from the Mediterranean Sea.
It can reach up to 4 feet tall and keeps itself in place using some 20,000 fine, sticky threads.
The threads can be removed, cleaned up and woven into a fine, golden fabric known as byssus cloth or sea silk.
This stuff has been popular and extremely expensive for over 2,000 years. Very few people remember the craft of its manufacture these days, which is just as well since there aren’t as many Noble Sea Pens around as there used to be.
Still, it’s always nice to have an utterly unexpected source for fabric now that we’re all accustomed to silk coming from a caterpillar.