Wedding: Anniversaries: A "ruby" wedding anniversary is celebrated after how many years.?

Questions

These marine crustaceans often attach themselves to the hulls of ships.?

This animal is armed with bony plates and rolls up into a ball if frightened.?

This animal is kept as a house pet to kill cobras.?

This animal is normally measured in "hands".?

This animal is the symbol of the U.S. Democratic Party.?