Why does the poet use the term ‘noble‘ and ‘wild‘ for the tiger?

The poet has ironically used the two contradictory terms, ‘noble’ and ‘wild’ for the tiger in the poem ‘How to Tell Wild Animals’. The tiger is a wild beast. It hunts and kills its prey only when it is hungry. Unlike other wild animals, a tiger doesn’t hunt or kill its prey for pleasure. The poet has cleverly brought out the humour through these words.