The river is a complex, rich symbol with many meanings: At its most literal, it represents the flow of nature. But since the poem simultaneously functions as a metaphor and an allegory, the river can symbolize life, time, and existence. Like time, the river constantly flows, but is filled with unexpected events—such as the sudden approach of a predator. The river also symbolizes existence which humans have to navigate. This existence is often governed with forces beyond human control; though humans try to swim across the river of existence, they cannot stay alert to all the forces comprising the river. The speaker details these variables, by looking “upriver” (Line 8) and “downriver” (Line 11), at the river’s current, its breadth, and its banks.

That the river involves so much unpredictability makes it a symbol of something vast and unknowable for humans. In its benign aspect, this is nature whose flow is peaceful; the fact that the crocodile and anaconda can navigate the river better than the monkey symbolizes that those who live in harmony with nature (thus, in their natural habitat) fare better than those who try to disrupt the natural order. In its more threatening avatar, the river symbolizes an unpredictable life, and an existence beyond the control of humans.