People living in Indonesian coastal villages discard coconut shells into the sea after use. When the octopuses come across these on the seabed, they drape their bodies over and around the shells, hollow-side up, leaving their eight arms dangling over the edges.The octopuses then lift the shells by making their arms rigid, before tiptoeing away in a manoeuvre Finn calls stilt-walking.
via Octopuses use coconut shells as portable shelters – life – 14 December 2009 – New Scientist.
The article also states that
There is a growing record of tool use in animals and birds, from musical “instruments” made by orang-utans
to sponges used by dolphins to dislodge prey from sand.
Here is my little random and definitely not scientifically supported theory. In fact, come to think of it, it would make for a great science fiction plot.
In the age of the dinosaurs, when they were the dominant species on this planet, our ancestors were like these creatures in the NewScientist article.
Our ancestors were learning about their environment, learning to use tools and developing the brain power to alter their environment to suit their needs as opposed to altering their needs to suit the environment.
Now in our time, we are the dominant species on this planet while those creatures mentioned in the article will be the ancestors of the next new dominant species on the planet.
When we have caused the next ice age, our species might die off, or it might say stagnant or in hibernation, severely diminished in numbers, to wait out the cold. The temperatures deep under the ocean might not change all that much, allowing life there to continue evolving.
Many years later, we “wake up” to a nice new warmer planet, and discover some pretty technologically advanced neighbours who have found their way from the sea to the surface.