Cowries' attractive colors, jewel-like gloss, and wide diversity make them the most popular group with collectors.  This beauty is possible because the mantle is external, building the shell from the outside and keeping it protected, whereas most other shells are built from the inside, with the oldest outer portion exposed.  The mantle usually has ornate papillae that provides camouflage and greater surface area for repiration.  In some species the mantle resembles its preferred food or habitat.

Juveniles look nothing like adults, resembling paper-thin olive shells.  Coiling as they grow until maturity, when the outer lip turns inward, forms teeth, and the shell thickens, applying the familiar adult pattern.  The length of an adult cowry is finalized at this point, and additional growth is limited to width and thickness.  Curiously, young cowries stop coiling at random lengths, resulting in mature shells of varying size.  Beachworn cowries may reveal the inner, contrasting juvenile color layers, in some cases this is purple.

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 fully intact shells are usually the result of predation by cone shells, while an octopus bite creates a jagged hole, and crustaceans, rays, and emperor fish crush shells into several pieces.  Cowries graze upon algae or sponge, licking the surface with a rasp-like 'tongue'  called the radula.  The radula is roughly 15% the shell length, a few millimeters wide, and worn teeth are continuously replaced.  Differences in radular teeth are used as an identification tool by malacologists.

Hawaii has several endemic cowries, prized by collectors around the world.  Some are rare such as live-collected Ostergaard's cowries worth several thousand dollars.  For unknown reasons, some common Indo-Pacific species are rare locally, and tend to be larger than average.

Proper care must be exercised to avoid ruining cowries.  Never boil, soak, use bleach, acid, or leave decaying flesh in contact with the shell.  Colors are water-based pigments that fade as the shell ages.  Avoid bright light and store in total darkness to slow this process.  If the gloss is damaged, nothing can be done to restore it aside from applying mineral oil.

HAWAIIAN TIGER COWRY 

 Monetaria caputophidii

HAWAIIAN SNAKEHEAD COWRY 

CHECKERED COWRY 

LEVIATHAN COWRY 

GROOVE-TOOTHED COWRY 

ALICE'S COWRY 

Ovatipsa rashleighana

RASHLEIGH'S COWRY 

BURGESS' COWRY 

HAWAIIAN CHICK-PEA COWRY

Purpuradusta fimbriata unifasciata

FRINGED COWRY 

OSTERGAARD'S COWRY 

HAWAIIAN HONEY COWRY 

HALF-SWIMMER COWRY 

ANNA'S HALF-SWIMMER COWRY 

GRANULATED COWRY, juv 

GRANULATED COWRY 

Nucleolaria granulata x nucleus

GLOSSY GRANULATED COWRY 

Nucleolaria nucleus x granulata

FALSE NUCLEAR COWRY 

MAUI'S COWRY 

WATT'S MAUI'S COWRY 

HAWAIIAN RETICULATED COWRY

HUMPBACK COWRY

ISABELLA COWRY

Lyncina schilderorum

SCHILDER'S COWRY

GASKOIN'S COWRY

Naria cernica cernica

WAXY COWRY

Naria beckii

BECK'S COWRY

POROUS COWRY

CALF COWRY

LYNX COWRY

CHINESE COWRY

ALISON'S COWRY

JESTER COWRY

 Talparia talpa

MOLE COWRY

Monetaria moneta

MONEY COWRY

Annepona mariae

MARIA'S COWRY

Lyncina propinqua

CLOSELY-RELATED CARNELIAN COWRY

Ipsa childreni

CHILDREN'S COWRY

NUCLEAR COWRY

ARABIAN COWRY

(waifs in Hawaii)

Staphylaea staphylaea

GRAPE COWRY

(waifs in Hawaii)

Staphylaea limacina

SLUG-LIKE COWRY

(waifs in Hawaii)

ERODED COWRY

(waifs & subfossils in Hawaii)

LINED-LIP COWRY

(waifs in Hawaii)

Erronea errones

ERRONEOUS or WANDERING COWRY

(waifs in Hawaii)

LITTLE ARABIAN COWRY

(waifs in Hawaii)

ROBERTS' COWRY

(waifs in Hawaii)

Eratoids are similar in appearance to ovulid cowries and very similar in biology to Trivia cowries, as they also live and prey upon compound tunicates.  Most are tiny, measuring less than 0.2 inch, or 6 mm, at adulthood.

HAWAIIAN ERATO

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.

STOUT VOLVA

ROSEWATER'S VOLVA

EGG COWRY

FLAMINGO TONGUE

FLAMINGO TONGUE

FINGERPRINT CYPHOMA