If your kids think coin collecting is for the birds, tell them they’re absolutely right…and that it’s also for the beavers, the butterflies, and the Barbary apes. Many countries around the world depict animals on their currency—most offer up no-brainers like the kangaroos on the Australian dollar. Others are a bit of a head-scratcher: Was a rat really the only option for the 10-shilling piece from Somalia?For numismatists, the best resource is Coin Lode (530/345-7969; coinlode.com), which trades exclusively in coins with critters on them. But you don’t have to be a die-hard collector to pick up some loose change on your next trip. Whether you save a bonefish from the Bahamas or a sea horse from Singapore, these coins provide an opportunity to learn about geography and zoology at the same time. Best of all, the exchange rate on fun never fluctuates.