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 several thousand dollars.  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.

HAWAIIAN RETICULATED COWRY 

 Cypraea (Monetaria) caputophidii

HAWAIIAN SNAKEHEAD COWRY 

HAWAIIAN TIGER COWRY 

HUMPBACK COWRY

Cypraea (Lyncina) carneola propinqua

CARNELIAN COWRY

HAWAIIAN LEVIATHAN COWRY 

GROOVE-TOOTHED COWRY 

Cypraea (Lyncina) schilderorum

SCHILDER'S COWRY

CHECKERED COWRY 

ISABELLA COWRY

ALISON'S COWRY

BURGESS' COWRY 

Cypraea (Talostolida) rashleighana

RASHLEIGH'S COWRY 

Cypraea (Purpuradusta) fimbriata waikikiensis

FRINGED COWRY 

Cypraea (Erosaria) cernica cernica

WAXY COWRY

GASKOIN'S COWRY

Cypraea (Erosaria) beckii

BECK'S COWRY

OSTERGAARD'S COWRY 

POROUS COWRY

HAWAIIAN HONEY COWRY 

HALF-SWIMMER COWRY 

ANNA'S HALF-SWIMMER COWRY 

GRANULATED COWRY 

Cypraea (Nucleolaria) pseudonucleus

FALSE NUCLEAR COWRY 

CALF COWRY

LYNX COWRY

CLEAR CHINESE COWRY

JESTER COWRY

HAWAIIAN CHICK-PEA COWRY

MAUI'S COWRY 

Cypraea (Talparia) talpa

MOLE COWRY

 Cypraea (Monetaria) moneta

MONEY COWRY

ERODED COWRY

Ovulids are similar in appearance to cowries but lack teeth along the aperture.  They live and feed upon soft corals, gorgonians, and black corals.  Their shells are quite drab but the mantle of live animals can be very attractive.

ROSEWATER'S VOLVA