Conchologists also admire this species, since its variability is seemingly unlimited: many common species BECOME common by developing a wide variety of adaptive features - i.e., by becoming a "generalist" or weedy species that can thrive in a variety of habitats in large numbers. Cypraea tigris L. has such a huge range of pattern and color variation that some collectors have large collections devoted to just this extraordinary species.

1) Genetic anomalies: genetic "freaks" are more common in variable species such as C. tigisL., since they probably became so variable by mutating more frequently than more uniform spp.  They are often rather difficult to distinguish from the other categories of abnormalities - only some rather detailed DNA work would tell you for certain!  Albinism is a good example of a genetic abnormality - it is a lack of pigmentation, resulting in a pure white shell. In some species this appears to be nearly always lethal ( C. tigris L. being one - albino specimens are rarer than oil companies losing money!), but in other species it is rather benign, and albino shells are often found.  Most pattern extremes are also the result of infrequent mutations - these usually cannot properly be called abnormalities or "freaks",  but they can be strikingly attractive at times!!

2) Injury-related abnormalities:  When a mollusc is injured, it is often able to repair the damage, but sometimes the part of the animal that secretes and tends the shell - the "mantle", is permanently altered, often resulting in strange and wonderful sights, since it changes the appearance of the shell in interesting ways. 

3) Disease-related anomalies: All living organisms are subject to diseases - molluscs included.  Quite often, a disease can change the way the shell is deposited - through its effect on the mantle. Some C. tigris L. specimens, for example, are extremely heavy, unusually large, with a heavily calloused, mottled appearance - not "pretty" by any standards, but fascinating nevertheless!!

4) Environmental factors:  If a mollusc grows up or moves to an area where conditions are difficult to live in or are simply quite different than the usual conditions the species inhabits, its shell often reflects these conditions in extremely interesting ways.  For example, an excess of nickel or zinc in the water can produce melanism, which is the deposition of extra dark pigmentation - completely melanistic specimens can be absolutely black!!  Extra iron can produce "rusty" colors, and various other elements produce other colors or affect the shell in other ways.  Man-made pollutants can cause interesting effects as well - for example phosphate pollution due to detergents or farm fertilizers, can cause certain species of Cypraea to acquire a strange red pigmentation.

The specimen on the right shows a forked "sulcus" (in life, cowries almost always cover  and protect their shells with the mantle - which is why they can remain so shiny, and almost never acquire barnacles, coraline algae, bryozoans, serpulid worm tubes, or any of the other "epiphyte" fauna that so often colonize shells.  Where the two sides of the mantle meet, a line often is formed, and is called the Sulcus.  The species which shows the best and most beautiful and variable sulci (recall this is a Latin word!) is Cypraea mappa L.)  - most likely the result of a mantle injury.  This particular malformation is extremely uncommon - of the thousands of tigris I've seen, this is the only one like it!