Autumn is the season in which the Earth cools off from the hot summer and starts a slow but sure trek to the colder months of winter. Autumn is the start of the harvest season for many plants, and both humans and animals gather crops and pack them for the coming winter.
The autumn equinox signals the first day of autumn. During autumn, the sunrise and sunset are approximately 12 hours apart everywhere in the globe. In the United States, many schools and universities have autumn terms, a time in which children, teenagers and young adults go back to school. Thanksgiving and Halloween are highly anticipated events during this season. Thanksgiving is traditionally observed to celebrate a bountiful harvest, and crops, such as pumpkins and apples, are harvested and used for soups, pies and Jack-o-lanterns.
Leaves of deciduous trees change colors in autumn and start falling off of trees. Some trees, such as weeping willows, lose all their leaves to survive the freezing months of winter. Trees start to reproduce and spread their seeds, which lay dormant on the ground throughout winter and start budding around spring. Animals, such as bears, marmots and lemurs, eat and build body fat for use as an energy source during their hibernation in winter. Autumn also kicks in the migration instincts of some birds.