The platypus, an aquatic mammal native to eastern Australia, is known for its unique features: a duck-like bill, beaver-like tail, and otter-like body, all adapted for its semi-aquatic lifestyle. It is also one of the few mammals that lay eggs, belonging to a group called monotremes. This article explores the platypus’s burrow systems, focusing on those built for reproduction and raising young.
Platypus Subterranean Shelters
Platypuses spend a significant portion of their lives within burrows dug into riverbanks. They construct various types of earthen shelters, primarily for resting and refuge from predators and environmental extremes. These general burrows, often called “camping burrows,” typically have entrances at or near the water’s edge, sometimes even underwater, and are usually difficult to spot due to concealment by vegetation or undercut banks.
Camping burrows are generally shorter, with platypuses often found resting less than 5 meters from the water’s edge. These shelters provide a secure place to sleep and offer thermal regulation, being cooler in summer and warmer in winter. While males and females generally lead solitary lives, multiple platypuses may occasionally use the same burrow, though typically not at the same time.
Crafting the Nursery Burrow
Female platypuses construct specialized nesting burrows for reproduction, which are considerably more elaborate than their general resting burrows. These nursery burrows are excavated into the riverbank and can extend significantly, sometimes reaching up to 30 meters in length. The entrance to a nesting burrow is typically oval-shaped, just large enough for an adult platypus to enter.
The female transports nesting materials, such as wet leaves, reeds, and grass, into the burrow by carrying them tucked between her hind feet and tail. These materials create a soft, insulated nest chamber at the burrow’s end. Throughout the burrow, the female creates a series of compacted soil plugs, or “pugs,” believed to deter predators, prevent flooding, and maintain stable temperature and humidity within the nesting chamber. The burrow itself can be a complex structure, featuring narrow tunnels, dead ends, and occasionally multiple entrances.
Life Cycles Within the Nest
Inside the carefully constructed nursery burrow, the platypus reproductive cycle unfolds. After a gestation period of about 16 to 21 days, the female lays one to three soft, leathery eggs, most often two. These eggs are incubated for about 6 to 10 days, during which the female curls her body around them, holding them pressed against her belly with her tail to keep them warm.
Upon hatching, the tiny, hairless young, known as “puggles,” emerge from their eggs with the aid of an egg tooth and a fleshy nub on their snout. Unlike most mammals, female platypuses do not possess nipples; instead, milk is secreted through specialized patches of skin on their abdomen, which the puggles lap up. The mother spends most of her time with her young in the burrow, leaving only for short foraging trips. Puggles remain in the insulated burrow, suckling for approximately three to four months, before they are fully furred and ready to emerge and begin foraging independently.