What is the meaning behind Lewis Carroll's "The Crocodile"?

How Doth the Little Crocodile is parody of moralistic poems. A moralistic poem is supposed to teach morals and good qualities. It's a parody of the poem Against Idleness and Mischief, by Isaac Watts (that's the poem that Alice was originally reciting, beginning "how doth the little busy bee"). The difference is that the bee poem was teaching the morals of good, hard work... While the crocodile poem is parodying it by 'teaching' that deception, trickery, and predation are desired qualities.