Series exploring strange animal behaviour looks at how a surprising number of creatures take substances for pleasure or to cure ailments. Discover starlings that use aromatherapy, chimps that administer their own medicine, an odd amphibian that can heal itself, bee bouncers that stop drunk and disorderly bees returning to the hive, monkeys whose liking for happy hour tells us about our own drinking habits, lemurs that ingest mind-altering millipedes, hedgehogs that indulge in strange rituals, cats that get high on plants and reindeer whose fondness for magic mushrooms may have spawned the greatest legend of them all.