Which primate uses a leaf as an umbrella to protect from rain?

Which primate uses a leaf as an umbrella to protect from rain? The orangutan is the answer. Wild orangutans have been observed using large leaves as makeshift umbrellas during tropical rainstorms.

This behavior is part of a much broader repertoire of orangutan tool use. They manipulate branches and leaves to scratch, wipe, sponge, swat insects, gather water, and create coverings over sleeping nests. A Sumatran orangutan has specifically been reported holding a large leaf overhead as rain protection.

Orangutans are especially notable for their flexible, problem-solving behavior. Their mostly arboreal lifestyle gives them access to abundant plant materials, and their long fingers and strong hands allow them to strip, bend, fray, and position branches and leaves precisely. Different populations can show different traditions in how tools are selected and used.

Chimpanzees and other apes also use tools, so the umbrella example should not be generalized into a claim that orangutans are the only tool-using primates. In this question, however, orangutan is the single canonical answer because the leaf-as-umbrella observation is specifically associated with the species.