"How doth the little crocodile improve his shining tail," is a line from Lewis Carroll's poem that depicts a crocodile's display of its bright, shimmering tail, suggesting a sense of pride or showiness. The poem describes the crocodile's joyful appearance as it seemingly grins cheerfully, with its claws spread neatly and its jaws smiling gently, giving off an innocent yet slightly mischievous demeanor.

The poem continues to portray the crocodile as welcoming tiny fish into its mouth, highlighting a playful and vivid imagery of nature. Carroll's words blend whimsy and vivid description, creating a lively picture of the crocodile's actions, capturing both the beauty and trickery of this creature in a charming, poetic manner.