From Keith Macpherson, Clevedon, Somerset, UK
Your article about chimpanzees seeking higher ground for tactical reasons reminds me of one of our cats. He would run upstairs for a better look if he saw something interesting in the back garden. What was curious was that not only did he have the nous to do this, he also had the orientation sense to know which rooms gave him the best vantage point (11 November, p 19).
