Every year on December 14th National Monkey Day celebrates unique characteristics of simians. The day also focuses on other non-human primates such as apes, tarsiers, and lemurs. Monkeys, also known as simians, live all over the world. More than 260 species of monkeys populate Africa, Central America, South America, and Asia. They range in size from mere ounces like the pygmy marmoset to the mandrill at a heavier 80 pounds and tend to walk on all four limbs. As a member of the primate family, they are considered a lesser ape. Most monkeys have a tail, though not all do. Monkeys are divided into two categories – Old World monkeys and New World monkeys. Their personalities and habits capture the attention of humans on many levels. These intelligent mammals with opposable thumbs live in family groups, too. However, many species of monkeys are endangered. Hashtags: #MonkeyDay