Pollination is the process of transferring pollen grains from the male anther of a flower to the female stigma. This is an essential part of plant reproduction, as it allows for the fertilization of the ovules and the production of seeds and fruit. Pollen can be transferred within the same flower (self-pollination) or between flowers of the same species (cross-pollination). Pollination can occur through various vectors, including wind, water, and animals such as birds, bees, butterflies, bats, and other insects. These animals or insects that transfer pollen from plant to plant are called "pollinators". Pollination is usually the unintended consequence of an animals activity on a flower, as the pollinator is often eating or collecting pollen for its protein and other nutritional characteristics or sipping nectar from the flower when pollen grains attach themselves to the animals body. Successful pollination requires year-round efforts, as plants evolved with differing flowering times that decrease competition among pollinators. Continuous blooms throughout the growing season provide pollinators with a constant food supply. Pollination is important because it ensures that a plant will produce full-bodied fruit and a full set of viable seeds. Many plants depend on animals, particularly insects, to transfer pollen as they forage. Plants attract pollinators in various ways, by offering pollen or nectar meals and by guiding them to the flower using scent and visual cues.