Chimpanzee Engineers

Scientific American:

When they are ready to snuggle up at the tops of trees, great apes make themselves cozy "nests" in which to rest for the night. New studies of these one-night nests reveal their incredible complexity.
"They are almost as complex as a man-made shelter you might make," study researcher A. Roland Ennos of the University of Manchester, in the United Kingdom, told LiveScience. "They know how the wood is going to break, and they have a feel for how strong they have to make it [the nest]. That shows the apes have intelligence and have a feel for the physics of their environment."
These nests are about 4 to 5 feet long and about 3 feet wide (1.2 to 1.5 meters long, and slightly less that 1 meter wide). The apes make them in the forest canopy, which can be between 30 and 60 feet (10 and 20 m) up, and it takes them only about 10 minutes to build. They use the nests only once, and then move on. The nests keep them warmer, away from insects and keep them safe, up off the forest floor.

That is pretty sweet.  It is likely that apes and engineers also share some hygiene traits.