Oyster (Books)

Oysters are molluscs mentioned in the How to Train Your Dragon Book series.

Description
The term 'oyster' may actually refer to members of several families of bivalves (Class Bivalva) rather than a specific grouping. Examples are the Family Ostreidae or True Oysters, and Family Pteriidae or Feathered Oysters. Though all oysters and other bivalves have the potential to produce pearls, members of the feathered oyster family are most known commericially as 'pearl oysters'.

Generally, oysters consist of two asymmetrical shells, or valves. Oysters are filter feeders, pulling in water across their gills, where debris and creatures such as Plankton become trapped and digested. Adult oysters are sessile, adhering to a substrate and remaining immobile.

Function
Oysters are valuable as a food source, as well as pearl production. In the Book series, oysters are also mentioned as an item of barter. Particularly the in-universe book How to Train Your Dragon costs 1 smallish chicken and 20 oysters.

How to Train Your Dragon
Oysters are mentioned as part of the price for the book How to Train Your Dragon, by Professor Yobbish.