Animals can be very important to plant reproduction in two ways—spreading pollen and spreading seeds. Pollen contains a plant’s sperm. Some pollen just blows around in the wind, but this is very wasteful because a lot of that pollen will never fall on the female part of another plant of the same species. Many plants “pay” animals to deliver their pollen. They may provide sugar (nectar) to coax animals into visiting their flowers and pick up pollen. They only give the animal a little, so the animal has to go to another flower, where the pollen can fertilize another plant. Honeybees, hummingbirds, and some bats do this. Other plants attract pollinators in different ways. One plant attracts flies by smelling like dead animals. Another looks like a female insect and attracts male insects.

Fruit is another type of payment. An animal may eat a fruit in one area, by defecate (poop) in another place, so that seeds get carried to new areas with the bonus of a dab of fertilizer and moisture. A large animal may carry a larger fruit far away to eat it, the drop the seed. Some animals, like squirrels, collect nuts and hide them. They don’t find every nut they hide, so some will sprout in new places. Relationships where individuals of both species benefit are called mutualisms. Most fruit only becomes edible when the seed inside is mature. Why would this benefit the plant?

Animals help plants by pollinating them, and be helping to disperse seeds.The droppings of animals also fertilize plants.

Plants have different reproductive manners. For instance, flowering plants rely on insects to harvest pollen. One bee will travel to many different flowers in one day. When the bee collects the pollen in the flower from the stamen, it gets some of the pollen on it's body and legs; this pollen will be transferred to the next flower it visits, as the bee must pass by the pistil. This movement of pollen from one flower to another allows the plant to reproduce. Another example are fruit bearing plants - anything from apples to berries to cucumbers - essentially any food with a seed inside. When an animal eats these seeds, they are not processed in the body, so when they excrete them, the seeds are then in a new location, and can start growing. The transport of seeds from one location to another allows new plants to start without taking away resources from the original plant. Conifer trees (pine, spruce, fur, etc.) use their pinecones - there are seeds in there that can be eaten or distributed by mice and other animals. On a whole different note, there are some carnivorous plants, such as the Venus fly trap, or the Pitcher plant. These plants actually eat insects and small animals! It is important to understand as well that some plants are dependent on one animal to pollenate it each year, and if that animal goes extinct or has to move because of environmental conditions, the plant will die.

Animals help plant reproduction by helping spread plant pollen and seeds. For example, bees pollinate flowers, which is vital to spreading genes and reproducing. As a point of interest, insects actually co-evolved with flowering plants, which means that they evolved together over time, in a relationship that benefitted both the plants and the insects, and with a speed and success that would likely not have been possible without the relationship. As another example, many animals eat fruits, and then travel a long distance before they poop out the seeds. The travelling animal helps spread the seeds to far off places, and the manure acts as a fertilizer to help the seeds grow.

One way animals can help plant reproduction is by directly fertilizing them. This can be seen with insects that pollinate flowers. As they go from plant to plant, pollen grains stick to them and are deposited into the next flower. Animals can also help plant reproduction by dispersing seeds around in different areas. Seeds can stick to fur or be intentionally moved, such as when squirrels or birds pick them up and drop or bury them. Animals that eat seeds also disperse the seeds when the poop them out. Some plants have even evolved to where they can only propagate with the help of animals. A unique example of this is in the rainforests of Australia. There is a tree that produces egg- sized, purple fruit with a pit (seed) in the center. The seed cannot germinate unless it passes through the digestive tract of a large, primitive bird called a Cassowary.

Animals spread seeds around. This is called seed dispersal. By helping seeds get away from the parent plant and into new, uncolonized habitats, they increase not only the seeds' propensity to survive, but also allow plants to colonize new areas. In addition, the caching behavior of many rodents and some birds (caching seeds to eat them later) plants seeds so that they have an easier time sprouting.