Most of the primates are a sort of monkey called rhesus macaques. They are designated for use in scientific research, including experiments for COVID-19.
A team of researchers trained three Rhesus monkeys to associate 26 clearly different symbols consisting of numbers and selective letters with 0-25 drops of water or juice as a reward.
Rhesus monkeys, when left to their own devices will breathe through their noses with their mouth closed and their tongue resting on the soft palate, and they usally have properly functioning, straight teeth.