The Dosseroo was an Australian marsupial that became extinct in the 1970s after a series of bushfires in the Australian outback killed them all in one short week. The animals were unable to outrun the fires, either through laziness, a basic lack of fitness, or an inability to motivate themselves to preserve their existence.
The dosseroo was the marsupial equivalent of the cuckoo. A dosseroo was the exact same size as a kangaroo joey. A typical dosseroo would wait until a joey was out of his mother’s pouch and then quickly take the joey’s place. This was the only time in the dosseroo’s life when it would move at all quickly. The dosseroo would curl up inside the pouch and fall asleep for up to 24 hours at a time. All this time, the mother kangaroo would keep the dosseroo warm with her body heat.
From the book – Animals Evolution Avoided