Animal waste fertilises the environment and helps support the entire ecosystem. Some animals cut out the middle man, and their waste feeds other species directly.
Tree shrews are native to south-east Asia and feed on fruit, flowers and sap. They have an unusual habit of expelling waste at the same time as eating, and one plant has evolved to take advantage of that. The Rajah pitcher plant is shaped like a toilet, and that’s exactly what it is used as. Tree shrews are attracted to the sweet sap that oozes from the plant’s upper leaves, and position themselves above the bowl as they eat.
While the shrew feasts, it leaves its waste in the bowl of the plant. This feeds the plant and gives the shrew a reliable source of food. This is an example of mutualism, where different species form relationships based on mutual gain. The shrew gains food, and the plant gains the shrew’s… leftovers.
Image from flickr.com/photos/wodjamiff