Reference Terms
from Wikipedia, the free encyclopedia
Animal shell
A shell is a hard, rigid outer layer, which has evolved in a very wide variety of different animals, including mollusks, sea urchins, crustaceans, turtles and tortoises, armadillos, etc. Scientific names for this type of structure include exoskeleton, test, carapace, and peltidium.
The shells that are perhaps most familiar and most commonly encountered, both in the wild and for sale as decorative objects, are seashells, more precisely, the external shells of marine mollusks. These are usually primarily composed of calcium carbonate, in the form of calcite or aragonite crystallised out in an organic matrix. Calcium carbonate in mollusc shells can take different crystalline forms, one being nacre otherwise known as mother of pearl.
Other kinds of animal shells are made from chitin, bone and cartilage, or silica.
Related Stories
1
2
Plants & Animals News
February 27, 2026
Feb. 26, 2026 Biomolecular condensates were long believed to be simple liquid blobs inside cells. Researchers have now uncovered that some are actually supported by fine protein filaments forming an internal ...
Feb. 25, 2026 A lost cache of 250-million-year-old fossils from Australia has rewritten part of the story of life after Earth’s worst mass extinction. Instead of a single marine amphibian species, researchers ...
Feb. 24, 2026 Deep in the Congo Basin, vast peatlands quietly store enormous amounts of Earth’s carbon — but new research suggests this ancient vault may be leaking. Scientists studying Africa’s largest ...
Feb. 24, 2026 Researchers are engineering bacteria to invade tumors and consume them from the inside. Because tumor cores lack oxygen, they’re the perfect breeding ground for these microbes. The team added a genetic tweak that helps the bacteria survive longer ...
Feb. 22, 2026 Flea and tick medications trusted by pet owners worldwide may have an unexpected environmental cost. Scientists found that active ingredients from isoxazoline treatments pass into pet feces, exposing dung-feeding insects to toxic chemicals. These ...
Feb. 21, 2026 Deep inside a Romanian ice cave, locked away in a 5,000-year-old layer of ice, scientists have uncovered a bacterium with a startling secret: it’s resistant to many modern antibiotics. Despite predating the antibiotic era, this cold-loving microbe ...
Feb. 18, 2026 As the planet warms, many expected ecosystems to change faster and faster. Instead, a massive global study shows that species turnover has slowed by about one-third since the 1970s. Nature’s constant reshuffling appears to be driven more by ...
Feb. 17, 2026 Researchers investigating crops grown in soil contaminated by the 2015 mining disaster in Brazil discovered that toxic metals are moving from the earth into edible plants. Bananas, cassava, and cocoa were found to absorb elements like lead and ...
Feb. 16, 2026 Even Antarctica’s toughest native insect can’t escape the reach of plastic pollution. Scientists have discovered that Belgica antarctica — a tiny, rice-sized midge and the southernmost insect on Earth — is already ingesting microplastics in ...
Feb. 14, 2026 A new study shows that dogs and cats may be helping an invasive flatworm spread. Researchers analyzing over a decade of reports discovered the worm attached to pet fur. Its sticky mucus and ability to reproduce alone make it highly adaptable. Pets ...
Feb. 14, 2026 Scientists are launching an ambitious global effort to map the “human exposome” — the lifelong mix of environmental and chemical exposures that drive most diseases. Backed by new partnerships with governments, UNESCO, and international science ...
Feb. 12, 2026 A new scientific review challenges the headline-grabbing claim that Yellowstone’s returning wolves triggered one of the strongest trophic cascades on Earth. Researchers found that the reported 1,500% surge in willow growth was based on circular ...
Latest Headlines
updated 12:56 pm ET
Feb. 27, 2026 For decades, scientists believed a fertilized egg’s DNA began as a shapeless mass, only organizing itself once the embryo switched on its genes. But new research reveals that the genome is already ...
Feb. 27, 2026 Baby dinosaurs weren’t coddled like lion cubs or elephant calves—they were more like prehistoric latchkey kids. New research suggests that young ...
Feb. 26, 2026 The Old Irish Goat isn’t just part of folklore — it’s genetically linked to goats that lived in Ireland 3,000 years ago. Scientists analyzed ancient remains and discovered that today’s rare ...
Feb. 25, 2026 Mars’ frozen ice caps may be time capsules for ancient life. Lab experiments show that key building blocks of proteins can survive tens of millions of years in pure ice, even under relentless ...
Feb. 25, 2026 Horses have a vocal trick no one fully understood until now. Scientists have discovered that when a horse whinnies, it produces two completely different sounds at the same time. One is a deep tone ...
Feb. 24, 2026 A newly identified ichthyosaur from the UK’s Jurassic Coast is rewriting part of the prehistoric playbook. Nicknamed the “Sword Dragon of Dorset,” the three-meter-long marine reptile lived ...
Feb. 23, 2026 A century after Erwin Schrödinger sketched out a bold vision for how we perceive color, scientists have finally filled in the missing pieces. A Los Alamos team used advanced geometry to show that ...
Feb. 23, 2026 Cleaner wrasse have revealed a remarkable new side of fish intelligence. Marked with fake parasites, they used mirrors to inspect and remove the spots—far faster than seen in earlier tests. Even ...
Feb. 23, 2026 Deep in the heart of the Sahara, scientists have uncovered Spinosaurus mirabilis — a spectacular new predator crowned with a massive, ...
Feb. 22, 2026 Triceratops’ massive head may have been doing more than just showing off those famous horns. Using CT scans and 3D reconstructions of fossil skulls, researchers uncovered a surprisingly complex ...