Identifying Metaphor in Literary Analysis

Read the following excerpt from a literary analysis:

"In the poem, the speaker portrays the city as a wounded beast, its cries echoing in the night, as its pulse quickens with the frenetic energy of life. This metaphor captures not only the physical state of the city but also reflects the emotional turmoil of its inhabitants, suggesting that urban life, while vibrant, can be profoundly isolating."

What figurative language technique is primarily employed in the description of the city as a 'wounded beast'?