The overlapping, interlocking food webs span from bacteria and other microscopic species with life cycles of hours, through to certain birds and reptiles which can exist for more than one hundred years. Sometimes roles reverse as species mature. Foxes, which one would normally classify as carnivores, will sometimes live exclusively on fruits and bulbs. At other times, they might eat beetles, cockroaches and worms. Around rubbish dumps they will scavenge crusts of bread and other food refuse.
Dietary preferences can be very broad or dangerously narrow.
They can change with seasons, and climate. Sometimes the dietary preferences of males and females of a species differ. As mentioned last month, the age structure of a population of wild animals is important to its survival in a number of ways. Adults from one species, for example predatory birds like the kookaburra, often prey upon reptile species including tree snakes. In turn, tree snakes prey upon the eggs and hatchlings of bird species including the kookaburra.