Cowries are a favorite of collectors because of their beautiful colors and high-gloss finish.  This is possible because the animals' mantle is on the outside, secreting the shell from the top-down and keeping it protected, whereas most other shells are secreted from the inside-out, hence the glossy interior of many shells.  The mantle is usually ornamented with papillae that provide camouflage and assist in respiration.  The color of the mantle sometimes matches the sponge it feeds upon.  Cowries usually remain hidden during the day in holes, dead coral heads, rubble, or under rocks and emerge at night to feed with the mantle fully extended.  Empty but intact shells are usually the result of predation by cone shells.

Cowries may be algal grazers or sponge grazers, or both.  Females lay a cluster of small egg capsules and will sit upon the mass until they hatch.  If you find a cowry clinging tightly to an egg mass do not disturb it otherwise it may not return to that position.  Veliger larvae hatch and spend some time in the plankton before settlement.  Juveniles look like paper-thin olive shells, coiling as they grow until maturity, when the outer lip curves inward, forms teeth, and the shell thickens with a new adult color pattern.  The height of an adult cowry does not change once this takes place but rather the shell thickens and the interior is dissolved to create more space inside.  Curiously, young cowries stop coiling at random regardless of height, resulting in a broad size range in adults.

Hawaii is special for having several endemic cowries, some of these being quite rare, such as live-collected Ostergaard's cowries worth $2000 or more.  Widespread species often attain record size in Hawaiian waters and many of these are rare locally.

Proper care must be exercised to avoid ruining cowries.  Never boil, soak in water, use bleach, acid, or leave decaying flesh in contact with the shell.  Keep out of direct sunlight and store in the dark to slow down the fading process.  If the gloss is already marred nothing can be done to fix it.

Ft. Kamehameha, Oahu, 4 feet

100 ft. Hole, Waikiki, Oahu, 85 feet

Juvenile, Makapu'u tidepool, Oahu

Fairly common on red sponge in dead coral heads, under rocks, and caverns.  The most slender and common of three similar-looking cowries in Hawaii.  Lacks dark spots on base, calloused only on outer lip.  Reaches 2.5 inches.  Feeds upon red sponge.

Very rare in the main Hawaiian Islands; more common at Midway and Kure.  Found on red sponge under rocks and caverns in shallow water.  Shell is thick and broad compared to Alison's Cowry with dark spots on base and calloused on both sides.  Reaches 2.5 inches.

Very rare in deeper scuba depths.  Found on red sponge under rocks, in dead coral, and caverns.  Stout thick shell without dark spots on base, calloused on both sides, fewer teeth than others.  About 1 inch.

Rare at depths greater than 60 feet.  Orange dorsum has small diffuse white spots, extremities with faint brown spots.  Base is white and lateral callus is pitted.  Attains 1.75 inch.

Makaha, Oahu, 35 feet

Juvenile, Makaha, Oahu, 35 feet

A beautiful endemic with a bright orange mantle.  Dorsum is bright orange with large yellow spots; prominent brown spots along base.  Feeds upon orange sponge in caverns.  Uncommon, it is less than 2 inches long.

North Shore, Oahu, 30 feet

Rare in rubble or caverns at scuba depths.  More inflated and extremities narrower than C. mauiensis.  About 1/2 inch.  Hawaiian shells are referred to as C. cicercula takahashii.

Kona, Hawaii, 30 feet 

Rare endemic species found under rocks or rubble.  Mostly found on Maui and Hawaii in shallow water.  About 1/2 inch.

Endemic to Hawaii.  Uncommon under rocks at scuba depths.  Dull rusty brown and flattened, juveniles are inflated and glossy.  Does not have elongated ends.  Up to 1.75 inch.  C. granulata cassiaui is found in French Polynesia.

Very rare under rocks at scuba depths in Hawaii, but fairly common throughout the Indo-Pacific..  Glossy tan, plump with protruding ends.  About 1 inch.

A rare endemic species found on black sponge.  Extremities are pitted and dark brown, light orange teeth distally elongate.  Less than 1 inch.  C. annae refers to the inflated form.

 Fish Hole, Midway, 35 feet

Ft. Kamehameha, Oahu, 6 feet

Makapu'u tidepool, Oahu

Makapu'u tidepool, Oahu

Ft. Kamehameha, Oahu, 3 feet

Sea Cave, Oahu, 65 feet

Common at scuba depths in dead coral and under rocks.  Base is orange-brown with purple terminal spots.  Hawaiian specimens' base color is persistent after death; others fade quickly.  Attains 1.5 inch.

Puako, Hawaii, 30 feet 

Infrequently found in dead coral at scuba depths.  Base is light purple with white teeth.  Less than 1 inch.

Hawaii, 60 feet 

Hawaii's rarest endemic species.  White base distinguishes it from Honey and Porous cowries.  Rarely found alive under coral rubble in deep water; usually found badly worn or broken.  Less than 1 inch.

Kewalo Hump, Oahu, 90 feet

Common in dead coral and under stones at scuba depths.  Animal is bright orange.  About 1/2 inch.

Makapu'u tidepool, Oahu 

Fairly common in small holes and under stones.  Mantle looks like black velvet.  May grow to nearly 3 inches; most are half that size at maturity.  Hawaiian specimens C. isabella controversa have dark brown terminal spots; other localities are orange.

Harbor, Midway, 10 feet

Rare in shallow water in Hawaii but common in the Indo-Pacific.  Prefers calm bays and harbors.  A thick shell with fine striations visible on the side.  Up to 3 inches.

Very rare in Hawaii under rocks in shallow water, but common throughout the Indo-Pacific.  Heavy shell with an abruptly-flattened base and orange teeth.  Reaches 2.5 inches.  Juveniles are white reticulated with orange.

Rare in Hawaii on red sponge under rocks at scuba depths.  Cream with orange teeth, purple dots and green reticulated dorsum.  Hawaiian shells are broad & depressed compared to the East African shell depicted.  Up to 2 inches.

Juvenile, Sharks Cove, Oahu, 25 feet

Ka'ohe, Hawaii, 20 feet

Juvenile, Makapu'u tidepool, Oahu

Mala Wharf, Maui, 20 feet

Common in rough shallow water in holes and under large slabs.  Juveniles are brown with numerous light zigzag patterns.  Attains 4 inches.

Uncommon in coral heads or rubble at scuba depths.  Attains 3 inches.

Kahe Point, Oahu, 30 feet

Juvenile

Juvenile, Puako, Hawaii

Makapu'u, Oahu, 10 feet

Found in dark holes along wave-washed basalt cliffs and seawalls.  Wave-driven debris tends to damage shell.  Large and heavy, it attains at least 4 inches.

Kaunolu Bay tidepool, Lana'i

Puako tidepool, Hawaii

Kaunolu Bay tidepool, Lana'i

Makapu'u tidepool, Oahu 

Juvenile, Makapu'u tidepool, Oahu 

Juvenile, Makapu'u tidepool, Oahu 

Abundant in the intertidal zone.  Inhabits sea urchin pits on benches and hides under rocks.  Juveniles are gray with a wide brown band.  Reaches 1.75 inch.

Kaena Point, Oahu, 30 feet

Locally common in caverns and under slabs exposed to surge.  C. carneola & C. propinqua are smaller, uncommon, and lack nodules on the side.  Attains 4 inches.

Uncommon under rocks at scuba depths.  Thick shell with white base and fine teeth.  About 2 inches.

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