Once again, we can take instruction from the koala, and other marsupials, this time about the importance of the oligosaccharide content of milk. Most marsupials have two teats, which are inside the pouch. Only one of these is used by the joey for the duration of its suckling life. If two joeys are born in two consecutive seasons, they each have their own teat. Remarkably, the two teats provide milk that is tailored to the age of each joey. The newborn receives milk high in oligosaccharides and low in lactose, whereas the older joey receives a lower dose of oligosaccharides, but far more lactose. Once a joey has left the pouch, the oligosaccharide content of its milk supply drops even further.