2. Auditory Signals: Animals also use auditory signals to communicate. For example, birds may sing songs to attract mates or to defend their territory. Frogs may croak to attract mates or to warn off predators.
3. Chemical Signals: Animals may also use chemical signals to communicate. For example, ants may leave behind a pheromone trail to guide other ants to food or to danger. Dogs may use urine marking to communicate with other dogs.