Hawaiian Cowries - Species Descriptions and Photos In this part of CoralRealm's coverage of Hawaiian cowries, John looks at the ten species most commonly encountered in Hawaiian waters.
Below I present the ten Hawaiian cowries most likely to be seen by divers. Five are endemic, others have wider distributions but are somewhat different in the Islands. All can be seen by divers or snorkelers in the Islands (especially night divers) although you would have to be very lucky and skillful to see the rare "half-swimmer" cowry which is almost invisible against the black sponge which it eats. At one time or another, I have found fresh dead shells of most of these on the sand at the bases of rocky walls or boulders or on the floor of caves. Likely they were consumed by predatory cones the night before. Ideally, one should leave them where they are, perhaps for hermit crabs to find and occupy; in practice I usually take these glossy beauties home. They are just too pretty to leave on the reef to be tumbled about and worn and covered with algae. Few hermits can live comfortably in cowry shells anyway--the living quarters are a bit too narrow. In Hawai`i, cowries are apt to be be much more common in some years than in others. Occasionally there are almost none to be found. There is no perceptible pattern to this. It probably depends on the vagaries of the currents carrying larvae (veligers) to the Islands. If you don't find any, try again next year!
Cypraea gaskoini Reeve, 1846 Although small, this is perhaps the loveliest of Hawaii's endemic cowries. Its shell is orange or orange-brown with numerous circular pale spots of varying sizes. A band of white at the base contains dark spots. The mantle and foot of the live animal are bright red. A flap of skin at the foot's posterior detaches readily to facilitate escape from predators. This cowry occurs from the shallows to depths of about 100 feet on cliffs and under ledges, hiding by day and emerging at night to feed almost exclusively on a species of red sponge. The name honors physician and naturalist John Samuel Gaskoin (1790-1858), surgeon to Kings George IV and William IV of England. The shell grows to a length of about 1 inch. Although considered endemic, it is similar to cowry species that occur elsewhere in the Pacific.
Cypraea granulata Pease, 1863 This unusual Hawaiian endemic has a pinkish brown shell covered with nodules. The white underside is beautifully grooved. The exposed animal, too, is extraordinary: so numerous and long are its papillae that it resembles a strange sea urchin or a tuft of finely branched red algae. The species occurs from shallow water down to at least 60 feet, usually near overhangs and caves; it is not common. The Hawaiian names for this cowry, leho `okala and leho opu`upu`u, mean "rough" or "bumpy." Curiously, subadult shells have a shiny finish like other cowries. It attains about 1 1/2 inches.
Cypraea leviathan Schilder & Schilder, 1938 This is the largest of three similar cowry species occurring in Hawai`i. All have creamy brown, cylindrical shells marked with darker red-brown bands; the undersides are white. Cypraea leviathan is best identified by its size and the large tufted "shaving brush" papillae (unique to the species) sprouting from the mottled gray and white mantle of the living animal. Shorter spikelike or branched papillae occur as well. In Hawai`i it inhabits caves and crevices, usually 30 feet. deep or less. Similar but slightly smaller cowries are likely to be either C. propinqua or C. carneola. Differences between the three lie more in size and form of the papillae than in shell coloration. In old Hawai`i shells of the large C. leviathan were sometimes used as octopus lures. An octopus captured with such a lure was said to have exceptional medicinal value. The Hawaiian name, leho pauhu, means "narrow-chested." To about 3 inches. Once considered endemic to Hawai`i, it is now recognized as an Indo-Pacific species.
Cypraea maculifera Schilder, 1932 This cowry's dark brown shell is usually overlaid by so many large, irregular white spots that a netlike effect results, hence the common name, meaning "like a net." The sides at the base are white with blurry dark spots. The mantle of the live animal is dark gray covered with fine, pointed, white papillae that give it a fuzzy appearance. The foot is dark gray. It is common in Hawai`i along rocky coasts where its relatively large size makes it an easy find in holes and under ledges from the shoreline to at least 50 feet. Hawaiian specimens tend to be larger than those found elsewhere. The species name means "dappled" or "spotted." The Hawaiian name, leho kolea, refers to the kolea, or Pacific Golden Plover, a migratory bird with a brown back with golden spots. It attains about 2 1/2 inches and ranges throughout the Central Pacific. It has also been found in Guam.
Cypraea mauritiana Linnaeus, 1758 This large handsome cowry is common along Hawai`i's black basalt shores as high as the mid-intertidal zone, especially in areas of heavy wave action. It seldom occurs on limestone but does occur on tuff deposits along O`ahu's southeast shore. The entire shell, including the underside, is brownish black. Irregular light marks dapple the back, which humps almost to a point. This shape and the thick, wide base help the animal withstand the force of pounding surf. The live animal's mantle is dark brown or black, matching the dark rock on which it lives. In old Hawai`i its flesh was eaten and the shell fashioned into scrapers for grating coconut, removing the skin from cooked taro or breadfruit, and preparing kapa (bark cloth). Perfect shells with fine spots and a dark reddish hue were called ipo (meaning "sweetheart" or "lover") and prized as lures for octopus. The species name comes from mauros, Greek for "dark." A large species, it attains almost 5 1/2 inches and has an Indo-Pacific distribution.
Cypraea sulcidentata Gray, 1824 This is probably the most abundant of the Hawaiian endemic cowries. The rounded shell is marked with four indistinct brown bands on a lighter background. At the base the sides are creamy brown to deep purple and finely marbled. The underside is light tan. The mantle of the live animal is tan marked with many fine, dark brown longitudinal lines. The many-branched papillae are broad, flat and white. The foot is light tan to white, the tentacles dark gray. This cowry is found under stones and ledges from depths of a few inches to at least 90 feet. The species name, meaning "grooved tooth," derives from the unusually deep grooves between the teeth that extend partly across the base. It attains about 1 1/2 inches.
Cypraea semiplota Mighels, 1845 This small, once-common Hawaiian endemic all but disappeared around the main islands in the 1940s and 1950s and was considered extinct by some. No one could explain the decline. The population has subsequently bloomed and fallen several times but never regained its former numbers. A more stable population may occur in the cooler Northwestern Hawaiian Islands. The back of the shell varies from dark brown to gray-white, well sprinkled with tiny white dots. The underside is white, the grooves between the teeth orange. The mantle, black with numerous papillae, is usually extended by day. The animal is associated with a sponge the same color as the mantle, but it also feeds on algae and can be kept successfully in a home aquarium. It occurs from shallow water to depths of at least 130 feet. The significance of the species name is obscure: semi means "half" and plotos means "floating" or "swimming." Broad, flattened whitish specimens are sometimes called C. annae Roberts, 1869. The beautiful Hawaiian name, puleholeho, means "dusk" or "twilight," possibly because the white spots on the dark background resemble stars. This endemic cowry attains almost 1 1/2 inches.
Cypraea talpa Linnaeus, 1758 This cowry's handsome shell is jet black around the base and on the underside; its back is brown, banded with gold. The mantle is black, densely covered with minute green spots and studded with broad, wartlike papillae. It is found both in sheltered waters and along exposed coasts at depths of at least 20 feet, but it is nowhere common. This cowry attains its largest size in Hawai`i. The common name comes from the species name, meaning "mole." It grows to about 3 1/2 inches and has an Indo-Pacific distribution.
Cypraea tessellata Swainson, 1822 This is perhaps the most famous Hawaiian endemic cowry. The best specimens have three large, dark, squarish spots set corner to corner, checkerboard fashion; more often there are only two with fainter squares at the corners. Either way, the pattern is unique. The back is lightly banded. The mantle is smooth and translucent, the shell markings showing through clearly. This cowry occurs from shallow water to depths of at least 200 feet, usually far back under ledges. It is uncommon and much sought after. The species name means "inlaid with small square stones" or "mosaic." It attains about 2 inches.
Cypraea tigris Linnaeus, 1758 Hawaiian waters produce the largest Tiger Cowries in the world. Although common throughout the Indo-Pacific, nowhere else do they attain such record sizes, sometimes 6 inches long. Surprisingly, these cowries were not officially recorded from Hawai`i until the 1930s. Dr. C.M. Burgess writes: "The first living specimen...was collected by the late Ted Dranga and Ditlev Thaanum in June, 1936.... The shell was seen in eighteen feet of water. Dranga dived for it and got it. The slippery beauty oozed from Mr. Thaanum's hands and Ted had the pleasure of diving for it a second time." The larger Tiger Cowries, extraordinarily beautiful, are now difficult to find. Although the pattern is simple, white with dark spots, the varying number and size of the spots can produce shells ranging from very light to almost solid black. It is said that no two are alike. The mantle is mottled dark gray with long, pointed, white-tipped papillae. This cowry is more likely to be seen by day than many others, probably because it is too big to hide effectively. In Hawai`i it usually occurs below about 10 feet. Elsewhere in the Indo-Pacific it ranges also into the intertidal. The species name denotes any of the large cats, many of which (like leopards) are spotted.
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