What makes the words for animal sounds an example of onomatopoeia?

The words used for animal sounds are an example of onomatopoeia because these words phonetically resemble the sound generated by the corresponding animals. These words attempt to imitate the actual sound that the animal produces. For instance, the word 'moo' is widely recognized as the imitation of the sound produced by a cow. These words provide a vivid representation of the sounds created by animals and are considered instances of onomatopoeia.