“Sometimes the birds would lose a tool, leaving it out of reach inside the cage.
In that case, they’d reach for another tool but wouldn’t use it to retrieve the
food—instead, they’d retrieve the first tool, then use that to get the food.
One individual went three layers deep into this sort of recursion.”
“From the perch atop the viewing tower, the spiders carefully surveyed the scene
before descending the tower and climbing up a walkway. Most [Portia jumping]
spiders chose the path that led to the meal, even if this meant moving away from
the prey and passing the incorrect walkway on the way.”