What are Chitons?
Chitons have a shell on their back made up of eight separate shell plates or valves. On different species, the plates have different colours, patterns, and textures. These plates are made from calcium carbonate and overlap a little at the front and back edges. The plates can still move separately. This means that the plates provide protection from above but still allow them to curl up into a ball if they are lifted.
There are between 900 to 1,000 species of Chiton worldwide, Australia has about 150 species and 90% of these are native to Australia. Most species are quite small (between 2 and 5 cm long). The largest rarely exceed 30cm. All chitons are marine, living, in both cold water and in the tropics, mostly in intertidal or subtidal zones.
They live on hard surfaces, such as on or under rocks, or hidden in rock crevices. Some species live quite high in the intertidal zone and are exposed to air and sunlight for many hours each day. A few species live in deep water, as deep as 6,000m.
Most of the body is a snail-like foot, but no head or other soft-parts beyond the girdle can be seen from above. Water flows into the mantle cavity through openings either side of the mouth, passes through the gills then leaves through an opening close to the anus.
Structure of a Chiton
Chitons have a heart with three chambers, two collect blood from the gills and the third pumps blood around the body. The mouth is on the underside of the animal, and a radula which has many rows of teeth.
What do Chitons eat?
Chitons eat algae, bryozoans, diatoms, barnacles. Sometimes they eat bacteria by scraping the rocky substrate with their well-developed radulae. Some chitons exhibit homing behaviour, returning to the same spot for the daylight hours and moving during the night to feed.
Nearly all chitons are grazing herbivores. The radula is used to scrape microscopic algae and even bacteria off the rocks they are grazing. A few species of chitons are predators eating other small invertebrates, such as shrimp and possibly even small fish. Some chitons exhibit homing behaviour, returning to the same spot for the daylight hours and moving during the night to feed.
Chitons are excellent cleaners of tanks. Their various colourings and patterns’ will make an excellent addition to your clean up crew. These charming and interesting critters are currently culturing in our tanks and will be ready in the coming weeks.
Habitat and Distribution of Chitons
As you delve deeper into the marine universe, you might come across an array of captivating creatures. Among them, chitons firmly grip our attention, quite literally. These armor-plated wonders are more than just their appearance, and their choice of residence and vast presence globally is nothing short of fascinating.
The Rocky Homes of Chitons
Have you ever skimmed your fingers across the uneven surface of a rocky shoreline? If yes, you’ve probably been closer to chitons than you realized. These marine creatures have a particular fondness for the rocky terrains of coastal regions. It’s on these very rocks, especially in the intertidal zones, where they firmly anchor themselves. The ruggedness provides them with a two-fold advantage: a generous buffet of algae, their primary diet, and a sturdy shield against potential predators. As tides ebb and flow, chitons go about their business, blending seamlessly with their rocky abode, making them masters of natural camouflage.
From Arctic Chill to Tropical Warmth: Chitons’ Global Footprint
If there’s one thing more impressive than a chiton’s sturdy armor, it’s their adaptability. They aren’t just confined to a single region or climate. From the icy waters of the Arctic and Antarctic to the temperate waves of the tropics, chitons have marked their presence. Each region witnesses chitons with distinct characteristics. For instance, the ones braving the cold might have heftier plates, while their tropical cousins might flaunt a splash of colors, harmonizing with the vibrant marine backdrop.
Chitons, with their global distribution and unmistakable affinity for rocky habitats, are an ode to nature’s adaptability and diversity. So, the next time you’re near a coastline, be it chilly or warm, take a moment to observe the rocks. You might just spot these marvelous mollusks, a true treasure of the marine world.