Why does he use ponies?

Just before the narration begins, the two ponies have come
out of the woods, as if to welcome the two representatives of another order of beings
(the speaker and friend). The present tense gives the poem immediacy, so that the
greeting appears to be happening before the speaker’s eyes. The setting with the ponies
is specific: The event is located in place and time, moving from physical concreteness
into the speaker’s more intense but less easily described feelings of satisfaction and
happiness. The realization that overtakes the speaker is that of the kinship, perhaps
even the “oneness,” of living things. Filled with love for the animals, the speaker
delights in the feel of the pony. At that point the speaker realizes that, could he or
she transcend the human body and its limitations, the true expression at the moment
could only be a transformation into a burst of blossoms.