What is the plural possessive for giraffe

Plural means more than one. Usually formed by adding an s. (giraffes, monkeys)

Possessives show ownership. Usually formed by adding an 's. (the giraffe's leaves, the monkey's bananas)

Plural possessives ... are both! (the giraffes's leaves, the monkeys's banannas)

Note that it is typical to drop the second s in this construction.

(the giraffes' leaves, the monkeys' bananas)

When the word ends with ff & ffe, you need to add "s". So, the Plural Possessive for Giraffe is Giraffes.