Why does the poem rhyme?

That is such a good spot. Rhyme is a really important part of poetry - it can completely change the tone of the poem. You can have rhyme at the end of a line, for example : 'cat' and 'bat'. This can give a rhythm to the poem, and make it more catchy and fast. If a poem is happy, a rhyme will often convey this, as it can make it fast paced. You can also have rhyme within a line, it doesn't just have to be at the end of the line. For example, the line 'the snake hissed for hours', is an example of sibilance. This is when there is a repeated 's' sound. This could create a menacing tone to the poem, as it reflects the sound of a snake hissing in reality.