The fruit of Sugar Maples is called the double samara, as samaras are found in pairs. Samara is a dry, indehiscent fruit, and a type of winged achene, with this wing formed by a wall or casing that extends to one side of the fruit. Samaras are often referred to as helicopter seeds as they spin through the air as they fall, similar to a helicopter. Usually only one of the paired samaras develops a small seed less than half an inch in size, though there are exceptions where both have seeds or neither, and some samaras have even been found in triplets, or a single samara has "double wings." The fruit takes about 16 weeks to ripen, changing from a light green to a light brown when fully ripe, and falls off the tree about 2 weeks after ripening, just before the leaves begin to fall. These fruits are also edible, eaten by many small mammals like squirrels and chipmunks, and edible for people too if the casing is first removed. However, since this method of dispersal by animals is quite minimal, the helicopter shape of the fruit is the main method of spreading seeds far away from the large canopies of the parent tree.