Bilbies are the largest of the bandicoots, a type of small Australian marsupial. Predation by feral cats has led to a decline in the bilbies' numbers; one species (the lesser bilby) is now believed to be extinct, and the other (the greater bilby) is an endangered species. Because bilbies are nocturnal and spend much of their time in underground burrows, what little is known about their behavior and life cycle is based on only a few recordings.
Bilbies have a very short gestation period--about two weeks long. At the end of this time, between one and four tiny (1/4-inch long) bilbies are born and crawl into the mother's pouch.
Far more time is spent in the pouch than in the mother's womb. The young bilbies remain completely enclosed in the tightly closed pouch until they emerge 75 to 80 days later in a process not unlike labor.
After emerging from the pouch, bilbies continue to nurse for a few days. They are fully grown and completely independent within two weeks.
Adult bilbies spend most of their time seeking food, mating and enlarging their burrows. Many are solitary, but some live in groups with up to three others.
Reproduction occurs almost year-round, and female bilbies often become pregnant while carrying young in their pouch. Bilbies have a brief lifespan of about three to five years, and reproduce many times during their lives.