Malacology is the study of mollusks. Museum researchers have databased over 100,000 mollusk specimens to date, which helps us understand more about biodiversity worldwide. Learn more >
Figure out how to tell your gastropods from your bivalves on this very informative FAQ page compiled by our resident malacologists.
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Our resident malacologists are making important contributions to educational research materials in their field. Learn more >
With more than 4.5 million specimens, our Malacology research collection is, by far, one of the largest at the Museum. The more than 200 specimens displayed in our shells exhibit are just a fraction of our behind-the-scenes collection. However, the exhibit showcases an intriguing and incredibly diverse mix of shells from around the world, including seashells, land and freshwater shells, as well as many rare, endangered and extinct shells. You’ll see a wide range of designs and colors. Shell sizes run the gamut too from 1.3 mm to a whopping three feet.
Tridacna gigas (Linnaeus, 1758)
The largest living species of bivalve is the Giant Clam of the western Pacific. The giant clam can measure up to 137 cm (3.7 ft.) and weigh 333 kg (734 lbs.). At one time people believed that the clam was a man-eater, but this myth turned out to be incorrect. In fact, the animal of the Giant Clam is so big that the shells cannot close — which would make it unlikely that the clam would be able to chomp on a person.
Papustyla pulcherrima (Rensch, 1931)
The high trees of Manus Island, Papua New Guinea are where these colorful snails make their usual home, although they are currently endangered due to habitat destruction. This particular species, Pupustyla pulcherima, is currently on the CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) list of protected species. The aim of CITES is to ensure that international trade in specimens of wild animals and plants does not threaten their survival.
Spondylus imperialis (Chenu, 1845)
These oysters' spines serve as protection and provide growth areas for barnacles and algae, which in turn provide camouflage. Although the Spondylus imperialis resembles oysters, these creatures are more closely related to scallops. Thorny Oysters live attached to hard substrates or other shells, and interspecific variability makes them difficult to identify with certainty.
Fossil abalone of the Cretaceous are extremely rare, previously only known from two species: one from San Diego County that is 70 million years old and another from Jamaica that is approximately 67 million years old). This local specimen from the Topanga Canyon area is 80 million years old and may help prove that abalone originated in Southern California.
Perotrochus hirasei (Pilsbry, 1903)
Slit shells have been termed "living fossils" as they were thought to be extinct since the Tertiary period. Recent additions to the living fauna in the last century have helped to link the fossil species with the modern species. Because the group lives in deep water many species are still considered rare.