Australian
Screen

Teacher’s notes

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This clip shows a platypus in the wild, seeking and eating its prey. In the early scenes the platypus emerges from a burrow and moves through the water as the narrator describes some of its distinctive traits. Next, the platypus is shown using its sensitive bill to hunt and then using the horny plates in its mouth to grind its prey, while the commentator explains how its various features operate. In the final scene the platypus continues its search for food. The sounds of gurgling water and haunting background music accompany the narration.

Educational value points

• The platypus (Ornithorhynchus anatinus) is an endangered species and among Australia’s most distinctive animals – one of only three living monotremes (egg-laying mammals) in the world and the only one that is amphibious. It is also the only mammal known to use a complex system of electroreceptors to locate its prey. Its scientific classification is Phylum: Chordata, Class: Mammalia, Subclass: Prototheria, Order: Monotremata, Family: Ornithorhynchidae.

• With its eyes and nostrils sealed under water, the platypus’s ability to obtain a three-dimensional sense of its prey depends on arrays of sensory receptors in its bill. The bill skin contains 40,000 of one type of electroreceptor and 13,500 of another type, enabling it to receive the electrical signals that emanate from prey such as worms and molluscs. There are also 46,500 mechanical receptors that pick up the mechanical displacement waves of moving prey.

• Unlike juveniles, which have three molars, adult platypuses have flattened horny plates, and the clip reveals their use in crushing and grinding food in close-ups filmed from below of the platypus 'chewing’ its food on the surface. The plates are sharp ridges near the front of the mouth but become flat towards the back. Grit probably acts as an abrasive. The platypus ejects anything it does not want through a series of horny serrations near both ends of its lower jaw.

• Found around permanent freshwater lakes and creeks in Queensland, New South Wales, Victoria, South Australia and Tasmania, platypuses occupy two types of burrows, nesting burrows and resting or camping burrows, that are dug into the banks of waterways or located in piles of accumulated debris. The burrow seen here is probably a nesting one as their entrances tend to be above the water level and are usually built among tree roots to prevent collapse.

• Platypuses are out of their burrows for up to 16 h of the day and night, spending much of this time foraging in water, and are well adapted to their aquatic environment. As seen in the clip, their body shape is streamlined, with fully webbed front feet used for propulsion, and partially webbed back feet used as rudders. Body temperature in the water is maintained by insulating body fur and an internal heat exchange system that minimises heat loss through extremities.

• The strangeness of the platypus is emphasised in the clip through the use of xylophone music. As the platypus dives under water seeking its prey, the eerie haunting sounds of the xylophone rise and fall, adding tension. The music in the clip was produced by music director Kevin Hocking (1932–) working with the Melbourne Symphony Orchestra. Hocking’s score for Nature of Australia won the French television award for best documentary score of the year.

• Images of a platypus underwater such as those shown here had rarely been seen by Australian audiences until the release of Nature of Australia, and the clip reveals the award-winning skills of nature documentary team David Parer and Elizabeth Parer-Cook. The couple spend a lot of time in the wild, producing many reels of footage using a wide variety of shots. Skillful editing presents viewers with a 'real-life’ experience of the platypus hunting and feeding.