The Octopus and the Orangutan: More True Tales of Animal Intrigue, Intelligence, and Ingenuity
This is one of my favorite animal books of all time. Eugene Linden has written a number of books about animal intelligence, and this was the first one of his I read. It describes how animals display intelligence in a number of ways, including tool use. Orangutans, for example, will often use a tool exactly how it is supposed to be used, while chimpanzees will use it for every purpose except the one for which it is intended! A captive octopus will often waste away and even die if not challenged enough, and their caretakers have to constantly dream up new food puzzles to keep them occupied.
My favorite story involves penguins who surprised their human neighbors with an activity that I won't describe, because it's too good for me to ruin it for you!
If you can find it at the library (the Schenectady library has a copy), or if you feel like ordering it, it's definitely worth your while to read. Linden's style is very easy; every book of his that I've read seems to fly past quickly. He's funny, compassionate, and breaks animal behavior down to a layman's level very well. If you have read this book, and you're interested in others by Linden, this is also very good:
The Parrot's Lament : And Other True Tales of Animal Intrigue, Intelligence, and Ingenuity
The Parrot's Lament is more descriptive of the emotional lives of animals, and how their feelings are demonstrated through intelligent behavior. After reading this, I came to realize that it's very difficult for humans to give pet parrots the emotional, social, and intellectual stimulation needed to be truly happy. I was also impressed at the trust and love displayed by animals in various circumstances. Again, it is also very easy to read, and while the scientific information is very easy for a novice to understand, it is not too simple to be enjoyed by a knowledgeable person.