You will be given a trivia clue, and the category it belongs to. You should answer with the best answer that belongs in the category and is described by the clue. For simplicity, answers should be in all lower cased letters.

Category: RULERS 
Clue: In 44 B.C. he was made dictator for life, a post abolished after he died the same year
julius caesar

Category: ANIMALS 
Clue: Odobenus, the genus name of this animal, comes from the Greek for "one who walks with his teeth"
walrus

Category: EUROPEAN CITIES 
Clue: By the river Lagan on the island of Ireland, it was chartered in 1613 & settled by Presbyterians & later Huguenots

belfast