Animals may not be able to speak but they have other ways of communicating... Whale song, wolf howls, frog croaks, bird chips -- even the waggle dance of the honeybee or the vigorous waving of a dog's tail -- are among the panoply of ways animals transmit information to each other and to other members of the animal kingdom.
They use nonverbal forms of communication, such as calls; non-vocal auditory outbursts, like the slap of a dolphin's tail on the water; bioluminescence; scent marking; chemical or tactile cues; visual signals and postural gestures.
Fireflies and peacocks are classic examples of brilliant bioluminescence and impressive visual displays, respectively. Ants use chemical cues (in a process called chemoreception) to help guide their foraging adventures, as well as for other activities like telling friend from foe or connecting with new mates.
When it comes to acoustic communication, not every member of a species is just alike. Animals in different regions have often been overhead sounding off in different dialects. For example, one study found that blue whales produce different patterns of pulses, tones and pitches depending on where they're from. Some bird species are the same way. And what about those birds that live on the border between territories of differing songsters? They often become bilingual, so to speak, and able to communicate in the singing parlance favored by each of their groups of neighbours!
Communication between species can play important roles as well. One study suggested that the reason Madagascan spiny-tailed iguanas have well-developed ears -- despite the fact that they don't communicate vocally -- is so they can hear the warning calls of the Madagascan paradise flycatcher. The two species have nothing in common except for the fact that they share a general habitat and raptors like to snack on them. So when an iguana hears a bird raise the alarm among other birds, it likely knows to be on alert for incoming predators, too!
To learn more on animal behaviour click here
To learn more on human non-verbal communication click here