Plants can’t move on their own, so they usually need a little help to spread their seeds far and wide. Sometimes wind or water will do the trick, but many plants have seeds that attract hungry animals with their sweet-smelling fruits and enticing flavors. Animals that scatter these seeds — often by eating the fruit and pooping out the remains — are known as seed dispersers

Seed dispersers are critical to any functioning ecosystem. A wide range of animals can act as seed dispersers, including birds, reptiles, and mammals like rodents or monkeys. Without these creatures, many plants would have very limited ranges — or wouldn’t be able to reproduce at all. 

In addition to spreading seeds, animal dispersers can help get baby plants off to a healthy start. They do this by breaking down seed casings in their digestive systems, and by sending seeds into the world surrounded by fertilizing dung. Other  seed dispersers, like gray squirrels and California scrub jays, hide and bury their seeds for later. When they inevitably forget where some of their stash is stored, the forgotten seed has a chance to grow where it is buried — often in shaded soil perfect for a young seedling. 

Brazil’s agouti tree is one plant that relies on animals to reproduce. Its fruits contain seeds covered in a hard husk that is almost impossible to crack. But a large rodent called the agouti can break open this outer shell with its powerful teeth. Some of the seeds it eats, and some it buries for later. You can watch this process bring an urban forest back to life in The Wild Hope episode Rewilding Rio.