![]() ![]() The platypus’s relatively low body temperature helps it to conserve energy, especially when swimming in cold water. This is lower than the body temperature of most other mammals – for example, the temperature of a healthy human is usually about 37 oC. The platypus normally maintains a body temperature close to 32 oC. The platypus ear is most sensitive to sound frequencies around 4 kilohertz (exactly the same as in humans) but can hear frequencies as high as 15 kilohertz. Platypus ears are generally like those of other mammals but do have a few primitive structural features -for example, the ear region is encased in cartilage rather than bone. The platypus ear is located in a muscular groove just behind the eye. However, a platypus very much relies on its eyesight as a way to detect predators when it’s swimming or resting on the water surface – the animals instantly dive if they see a bird (even a small, harmless one) swooping over them. It’s believed that this occurs to help protect the eyes from being injured accidentally by underwater branches and the like, and makes sense given that the platypus feeds mainly at night and often in murky water. Interestingly, the platypus rarely uses sight when underwater – its eyes normally close automatically as soon as it dives. The lens is fairly flat at the front and much more curved at the back, like those found in otters and sea lions. Its structure is mostly like that of other mammals but has some reptilian features, such as double retinal cone cells used to see colour. The platypus’s eye is small (6 millimetres in diameter) and has a round pupil. Photo courtesy of Ann Killeen (right), other photo: APC ![]() ![]() Because electricity travels so rapidly through water, the tail flick of a shrimp is recorded a fraction of an instant earlier by bill electroreceptors as compared to push rods, making it possible for a platypus to judge the distance to its prey. The bill surface is also thickly dotted with electroreceptors (technically known as “sensory mucous glands”) that are able to register the tiny amounts of electricity generated when the muscles of edible aquatic invertebrates contract. Nerves are activated when the tip of a push rod receptor is displaced by as little as 20 microns (0.00002 metre), which means that a platypus can detect movement by prey such as a freshwater shrimp from a distance of 15-20 centimetres, simply by sensing associated water movement. The receptors known as “push rods” are sensitive to touch or pressure. The skin of the bill contains tens of thousands of specialised sensory receptors that provide a platypus with the information it needs to navigate underwater and capture its prey. The bill’s upper surface is uniformly dark grey its lower surface can either be uniformly grey or quite mottled. The platypus’s bill is covered by smooth skin with a soft, suede-like texture and (unlike a duck’s bill) is quite pliable and fleshy around the edges. The extra skin folds under the foot when an animal leaves the water, making it easier to walk or to dig using the sturdy front claws. The front foot ends in a broad expanse of skin that unfurls in the water to form a large and efficient paddle (below). The platypus’s hind foot is equipped with sharp, curved claws that are used like a comb to groom the fur (as shown at left). The light-coloured patches make it look as if the eyes remain open, reducing the risk of attack by a predator (as shown above). The fur is dark brown above (except for a small light-coloured patch of fur next to each eye) and creamy white below (sometimes tinged rusty red or brassy yellow). The eyes and ears are both located in a muscular groove that normally pinches shut when a platypus dives. The platypus has a streamlined body and a superficially duck-like bill. A long-term study near Melbourne found that 40% of adults were last captured when 3-5 years old, 36% when 6-8 years old and 24% when 9 or more years old. Life span: Up to 21 years in the wild (males and females). Length of lactational period: 16-20 weeks (in captivity) Length of egg incubation period: 10-11 days Number of babies in a litter: 1-3 (most typically 2) Animals living in the colder/southern parts of the platypus’s range are generally larger than those found in the warmer/northern parts of its range.Īge when first mature: 2 years (males and females) Maximum recorded length = 0.6 metres.Īdult weight: Typical weight = 1.0-2.4 kilograms (males), 0.6-1.4 kilograms (females). In this section on platypus biology you can find information about:Īdult length: Typical total length = 0.5 metres (males), 0.4 metres (females). ![]()
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