Why do animal cells have small vacuoles whole plant cells have large vacuoles?

Plant cells have a large vacuole due to the amount of water the cell must hold to maintain its shape. The water in the vacuole creates something called turgor pressure. When the vacuole has lots of water, the turgor is high and pushes against the cell wall so the cell is rigid. When vacuole has little water, the turgor is low so the cell is flaccid.

Animal cells don't have to worry so much since our cells are already in an aqueous environment and get water in lots of other ways.