Clam (Franchise)

Clams are only mentioned twice in the How to Train Your Dragon Franchise.

Description
Clams are Molluscs in the Order Bivalvia, indicating they have two shells hinged together. Clam shells are generally equal in size and shape to each other. There are clam species that live in freshwater, but the majority of species live in salt water environments. Many have a strong "foot" with which to burrow into the sand or silt in their habitat. Some species live along the coastlines and emerge at high tide, then burrow into the sediment at low tide.

Function
Both in the Franchise and in reality, clams are seen as a food source for humans. Additionally in real life, clam shells sometimes serve as collectibles. Historically, some clam shells were used as beads and currency to some Eastern Native American tribes.

Dragons: Race to the Edge, Season 1
In "Dragon Eye of the Beholder, Part 2", the Dragon Riders have found the Dragon Eye and bring it back to Berk to figure out its purpose. As Gobber tries to unlock it, he harkens back to an old memory.

"I once opened a 500-year-old giant clam at the bottom of the ocean with my bare hook. Can I open it? Ha! I think it's going to be... Huh. Aha."

- Gobber in "Dragon Eye of the Beholder, Part 2"

School of Dragons
Clams are mentioned briefly in one of the "Farm Jobs" a player can complete by raising and harvesting crops for coins. This one involves growing tomatoes.

"Mulch wants to make soup with tomato base and clams."

- School of Dragons