Which literary device involves using animal characters to convey human traits?

The literary device that involves using animal characters to convey human traits is personification. This technique allows writers to give human qualities, emotions, and behaviors to non-human entities, such as animals. By portraying animals with human characteristics, authors can explore complex themes and moral lessons in a way that resonates with readers. This device is particularly effective in fables and allegories, where the animal characters represent human societies, behaviors, and values.

In contrast, metaphor and simile are focused on drawing comparisons between different entities but do not inherently involve the attribution of human traits to animals. Alliteration is a sound device used to create rhythm or emphasis in writing through the repetition of initial consonant sounds, which is unrelated to character traits or representation. Thus, personification is the most fitting choice for conveying human traits through animal characters.