Platypus mainly sleep in earthen burrows located at or near the water’s edge. They may also occasionally shelter in a cavity within a pile of logs and other woody debris in the stream channel (Serena 1994; Gardner and Serena 1995), inside a hollow log at the water’s edge (Burrell 1927), in manmade structures such as concrete stormwater drains (Thomas et al. 2019) or (in Tasmania) within a dense clump of low-growing vegetation (Otley et al. 2000). Apart from providing a secure place to sleep, an earthen platypus burrow is both cooler in summer and warmer in winter as compared to the temperature outside (Bethge et al. 2004).
Platypus burrows are divided into two types: nesting burrows and camping burrows.
A platypus nesting burrow provides shelter for a mother and her offspring for several consecutive months. It’s typically 3-6 metres long (measured in a straight line from the entrance to the nesting chamber), though it may be much longer, particularly along rivers that are routinely subject to major flooding in summer. The entrance is roughly oval in shape and just large enough to allow an adult platypus to enter (as shown at left).
Whenever a mother of young juveniles enters or exits her nesting burrow, she blocks the entry tunnel with a series of 2-9 compacted soil plugs (or “pugs”) (Burrell 1927). It’s believed that the pugs both deter predators from entering and help to protect juveniles from drowning if water levels rise after a storm.
Platypus camping burrows are occupied by individuals that are not incubating eggs or caring for young. Camping burrows are normally shorter than nesting burrows, with radio-tagged animals typically found resting less than 5 metres (and sometimes less than 1 metre) from the water’s edge (Serena 1994; Gardner and Serena 1995; Gust and Handasyde 1995; Thomas et al. 2017). Platypus camping burrow entrances are sometimes located underwater (Serena 1994) and are otherwise typically difficult to spot, as shown below (entrance locations marked by red arrows).
A platypus will normally occupy two or more camping burrows when tracked over a period of a few weeks, including some burrows that may be used by other individuals (Serena 1994; Gardner and Serena 1995; Gust and Handasyde 1995; Serena et al. 1998; Otley 2000; Thomas et al. 2019). For example, a radio-tracking study conducted along a stream in southern Victoria found that five animals (3 adult males, 2 adult or subadult females) each occupied between 6 and 12 burrows over periods of 28 to 38 days. Three animals occupied at least one burrow that was used at some point by another individual, though only one platypus burrow was occupied by two individuals at the same time (Serena et al. 1998).
Photos: APC
LITERATURE CITED
Bethge P, Munks S, Otley H and Nicol S (2004) Platypus burrow temperatures at a subalpine Tasmanian lake. Proceedings of the Linnean Society of New South Wales 125, 273-276.
Burrell H (1927) The Platypus. Angus & Robertson: Sydney.
Gardner JL and Serena M (1995) Spatial organisation and movement patterns of adult male platypus, Ornithorhynchus anatinus (Monotremata: Ornithorhynchidae). Australian Journal of Zoology 43, 91-103.
Gust N and Handasyde K (1995) Seasonal variation in the ranging behaviour of the platypus (Ornithorhychus anatinus) on the Goulburn River, Victoria. Australian Journal of Zoology 43, 193-208.
Otley HM, Munks SA and Hindell MA (2000) Activity patterns, movements and burrows of platypuses (Ornithorhynchus anatinus) in a sub-alpine Tasmanian lake. Australian Journal of Zoology 48, 701-713.
Serena M (1994) Use of time and space by platypus (Ornithorhynchus anatinus: Monotremata) along a Victorian stream. Journal of Zoology 232, 117-131.
Serena M, Thomas JL, Williams GA and Officer RCE (1998) Use of stream and river habitats by the platypus, Ornithorhynchus anatinus, in an urban fringe environment. Australian Journal of Zoology 46, 267-282.
Thomas JL, Parrott ML, Handasyde KA and Temple-Smith P (2019) Burrow use by juvenile platypuses (Ornithorhynchus anatinus) in their natal home range. Australian Mammalogy 100, 1182-1190.