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Episode 17: The Peculiar Platypus

The platypus (Ornithorhynchus anatinus) is one of, if not the most unique animal on the planet. This small mammal and their ancestors have survived for over 200 million years. Today, the platypus lives in Australia and despite their lineage surviving the last three mass extinctions, they may not survive this one.

Platypus Physiology

No doubt what makes the platypus so unique is their physiology. The best description is a cross between a beaver and duck. Thus, this animal earned the name the “duck-billed” platypus.

The male platypus measures 50 cm (20 inches) in length and can weigh up to 2.3 kg (5.2 lbs). Due to sexual dimorphism, females are slightly smaller. The platypus has the body of a beaver with brown fur that is waterproof. Their tail is very similar to a beaver, flat, and they have webbed feet which aids them in swimming.

One of the most unique features is obviously the bill, or nose of a platypus. The bill is actually feels quite rubbery and is covered in skin that has the feel of suede leather. Within the bill are very sensitive receptors which aid the platypus in its ability to electrolocate. Electrolocation is the ability of the animal to sense electrical fields of its prey. While swimming, a platypus will keep its eyes and ears closed and sense for its food in the murky water with its bill, using electrolocation.

Males have two venomous spurs on its hind legs. While not fatal to humans, the venom is quite painful that can persist for months.

Platypus is a mammal based on its ability to:

  • Thermoregulate its body temperature
  • Lactate- though its mammary glands are undeveloped, and the animal secretes milk through its skin pores
  • Hair on their bodies
  • Have three middle ear bones characteristic to mammals

The platypus does have reptilian or bird like characteristics. Most striking is their ability to reproduce by laying eggs. When the young hatch, they are quite underdeveloped, similar to marsupials, but not quite as helpless.

These animals are semi-aquatic and nocturnal. They get most of their diet from the rivers, lakes, or other fresh waterways where they live. They eat worms, small fish, crustaceans, insects and other small animals. While the platypus has no teeth, they rise to the surface when hunting and crush their prey between their bills and may even hold gravel in their mouth to act as teeth.

Platypus History

The platypus belongs to a class of mammals called Monotremes. The other monotreme species are the echidnas. The other two classifications of mammals are the marsupials (kangaroo, opossum, others) and the eutherians (human, elephant, others).

The evolution of the platypus stretched back almost 280 million years. Prior to the 3rd Mass Extinction, reptilian-like mammals existed. Many went extinct through the 3rd, 4th, and 5th Mass Extinctions. Yet, relatives of the platypus survived.

The monotremes split from the other mammalian lineages approximately 150 million years ago. The platypus is one of the most ancient mammals still existing on the planet.

Platypus Conservation

The platypus habitat is isolated to Australia and Tasmania. It is estimated there are populations of 30,000 or maybe up to 300,000. The population is in decline and the platypus has now been listed as near threatened. They have suffered a nearly 30% decline in their numbers due to human activities and with severe droughts.

Conservation Tip

Share this episode with one friend. Education about the plight of the platypus and other species is critical to making change across the planet.

Organizations to Support

Australian Platypus Conservancy

Taronga Zoo

 Reproduction Pictures

March 06, 2018
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