First published:
Creation
24(2):40–43
March 2002

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The platypus

Still more questions than answers for evolutionists

by Paula Weston

Imagine, if you will, the excited glances exchanged if paleontologists were to uncover a fossil that looked like a mammal, yet also had bird and reptilian features. The immediate reaction would probably be to declare that here was, clearly, a transitional creature that provided an evolutionary link between mammals and their non-mammalian ancestors.

That might well be the conclusion drawn if a platypus fossil were found today, without living examples around to indicate otherwise.

Did you know? Platypuses range in body length from 30–80 cm (12–32 inches) and weigh from about 1–10 kg (2–22 pounds); they feed mainly on insect larvae, small crayfish, tadpoles and other aquatic animals, and breed once a year; in captivity, they have an enormous appetite, able to eat the equivalent of half or more of their own body weight in a single day; they have teeth when they are young, which are shed before the animal becomes an adult, and are replaced by horny pads; their posture resembles that of reptiles, especially lizards; they have no external ears; they have cheek pouches in which food is stored until it can be chewed; webbing on the hind feet reaches to the base of the claws, and on the front feet beyond the claws, making extra large paddles for swimming; males have a sharp, movable, horny, poison ‘spur’ on the inner side of each hind limb near the heel. It is about 15 mm (0.6 in) long. It is believed to be used in territorial disputes between males in mating season (although nobody really knows for sure). Source: Encyclopaedia Britannica, 15th edition, 23:353–355, 1992.

The platypus has perplexed scientists since its discovery by Europeans in the late 18^th century. Here is a creature that has a furry body like most mammals, webbed feet and a bill like a duck, and a reproductive system that involves young being hatched from eggs before suckling from their mothers.

In fact, when the first platypus specimen reached England in 1799 (it was long dead), it was regarded as a hoax, a ‘high frolic practised on the scientific community by some colonial prankster’.¹ Experts of the day could not reconcile the fact that a duck-billed mammal with webbed feet and claws and a beaver-like tail could really exist. One zoologist, sure it was fraudulent, tried to remove the ‘duck’s bill’ from the pelt; his scissor-marks can still be seen on the original, in London’s British Museum of Natural History.

The creature was ultimately deemed to be genuine, but it took another 90 years of long and arduous investigation and experimentation before scientists had a better understanding of its complexities.

The platypus and the echidna (only found alive in Australia) are the only known monotremes—mammals that lay reptile-like eggs and suckle their young. But, even when suckling, they are not like other mammals; the milk is not produced through teats, but is apparently sucked from the skin as it exudes from the ducts of the mammary glands.²

In its natural habitat—lakes and streams in eastern Australia and Tasmania—the platypus reveals an amazing array of design features. It uses claws for burrowing and its webbed feet for swimming (the web, which extends beyond the claws, is folded under the palms when the platypus is on land), while its broad, flat tail helps with diving.² Fine fur, made up of 900 hairs covering each square millimetre of skin has two layers—a woolly undercoat and shiny longer hair—that keep most of the platypus’s body dry when diving.³

The platypus often swims along the surface, with only the upper part of the muzzle and a small part of the head above water. When it submerges, it has a fold of skin that closes over its eyes and ears.² Its duck-like bill is actually a sensitive muzzle that allows the platypus to find tiny food morsels at the bottom of murky lakes and rivers and under rocks using highly developed electro-receptors (see right).

For more than 100 years, debate has raged within the scientific community about various aspects of the platypus, muted only briefly and very occasionally by (very infrequent) new discoveries (such as the proof in 1884 that the creature laid eggs, rather than gave birth to live young).⁴

Of particular interest has been the creature’s origin. Encyclopaedia Britannica says that ‘little is known of their ancestry’ and: ‘Most authorities believe the order Monotremata originated from a line of mammal-like reptiles different from that which gave rise to the other mammals. Nonetheless monotremes may well represent features of anatomy and development that characterized the earliest mainstream mammals.’⁵

Scientists initially considered the platypus to be ‘primitive’, but then they discovered the incredibly complex electrolocation techniques the animal uses to find food. To evolutionists this made it a ‘highly evolved animal and not a primitive transition between reptiles and mammals.’⁶

The platypus, along with its fellow monotreme, the echidna, was believed to have evolved in isolation when the land mass that would become Australia (Gondwana) broke away from the other continents supposedly 225 million years ago.⁷ This idea of evolution in isolation followed the theory of Darwin, whose affinity for evolution may also have been influenced by his early studies of the platypus during his time on The Beagle.⁸

However, the discovery in the early 1990s of three platypus teeth in South America—almost identical to fossil platypus teeth found in Australia—threw that theory upside down.⁹ (Marsupials, too, were once considered to be exclusive to Australia, but their fossils have now been found on every continent.) Adult living platypuses do not have teeth, but the discovery of platypus fossils in Australia had already identified that their ancestors did have teeth, which were unique and distinctive.¹⁰

In reality, there is nothing in the fossil record to indicate that the platypus was ever anything other than a platypus. It is not a living ‘transitional’ form. It is a truly unique creature, and one that continues to baffle those who insist on making it fit into an evolutionary tree.

The skeleton of a platypus on display at a Gold Coast, Australia, exhibition of Ripley’s Believe it or Not.

Platypus patter

• The birth of the first platypus in captivity in 1944 at Healesville Sanctuary (outside Melbourne, Australia) was such big news it made headlines around the world, despite the fact World War II was still raging. She was named Corrie and was born under the care of zoologist David Fleay.¹
• It took 47 years for another birth in captivity—in 1991 at Warrawong Sanctuary in South Australia.² Then in 1999, Healesville again made headlines with the rare birth of twins in captivity.³
• The platypus is extremely difficult to breed in captivity. Experts say this is because it is so secretive and shy in nature. It also likes routine and order in its life. Creating a habitat in which it feels perfectly at home is considered the greatest secret in successful breeding.⁴
• In 1943, Winston Churchill requested David Fleay send him six live platypuses from Australia. Fleay, knowing how difficult it was for his animals to travel, settled on sending just one. Named ‘Winston’, he was placed in a platypusary specially designed to handle the long sea voyage on the MV Port Phillip, along with a huge supply of his favourite food. Remarkably, Winston was thriving on the ship until it was forced to launch a depth charge against a submarine. The nerve receptors in his highly sensitive bill could not cope with the violent explosion, and he died. Winston did make it to England, but the British Prime Minister had to settle for his new pet being mounted on his desk.⁵
• Thousands of platypuses were killed by zoologists in the 19^th century in the race to uncover the ‘mystery’ surrounding the fascinating creature.⁶

References

1. Moyal, A., Platypus, Allen and Unwin, New South Wales, Australia, p. 184, 2001. Return to text.
2. Warrawong Sanctuary, <www.burkesbackyard.com.au/facts/conservation/warrawong_35.html>, 15 November 2001. Return to text.
3. Sanctuaries: A haven for Australia’s forgotten species, <www.2docstock. com/Sanctuary/>, 15 November 2001. Return to text.
4. Healesville Sanctuary’s platypus baby—a history making success 2, <www.zoo.org.au/newspage.cfm?p=275>, 15 November 2001. Return to text.
5. Ref. 1, p. 180–185. Return to text.
6. Ref. 1, p. 157. Return to text.

Electro-reception

One of the most amazing design features of the platypus is its bill, which has fine nerve receptors that allow it to pick up electric fields given off by shrimp and other prey.

This is particularly important for the platypus, as it hunts for its food at the murky bottom of lakes and rivers—and does so with its eyes shut.

It was once thought the animal ‘blundered’ around on the bottom, but instead, it is actually carefully detecting prey tucked away in mud, sometimes even under rocks. The favourite food of the platypus is the freshwater shrimp. This creature generates an electric field through the flipping of its tail which the platypus can detect from 10 cm away.¹

The freshwater paddlefish (or spoonbill) is another such creature that uses electro-reception. Its poorly functional eyes are of no use when it searches for its stock food, the tiny water flea. Scientists have discovered that the paddlefish’s nose (or paddle) has thousands of tiny pores that function as electro-receptors. These sensory pores extend from the paddle to the top of the head and the gill covers, occupying nearly half of the skin surface of the fish.²

The paddlefish and platypus join a catalogue of aquatic animals equipped with electro-sense. However, the platypus’s system varies slightly, in that an electric stimulus excites the nerve fibres directly, not through the use of a chemical mediator as found in some marine and freshwater fish.

In other words, there are two distinctively different electro-sensory systems of which the scientific community is aware. The possibility that evolution could produce two such effective systems requires an enormous amount of faith in blind mutations (genetic mistakes) favoured by selection.

References

1. Moyal, A., Platypus, Allen and Unwin, New South Wales, Australia, p. 189, 2001. Return to text.
2. Missouri Conservationist , p. 17, January 2001. Return to text.

References and notes

1. Moyal, A., Platypus, Allen and Unwin, New South Wales, Australia, p. xii, 2001. Return to text.
2. Encyclopaedia Britannica , 15^th edition, 23:354, 1992. Return to text.
3. Ref. 1, p. 204. Return to text.
4. Ref. 1, p. 152. Return to text.
5. Encyclopaedia Britannica, 15 ^th edition, 8:266, 1992. Return to text.
6. Ref. 1, p. 191. Return to text.
7. Ref. 1, p. 192. Return to text.
8. Ref. 1, p. 107. Darwin was 22 years old when he set off in 1831 to spend four years on The Beagle as a naturalist. The voyage included landfalls in South America, the Galápagos Islands, New Zealand and Australia. He published On The Origin of Species in 1859. Return to text.
9. Creation 15(3):8, 1993; Creation 14(1):13, 1991. Return to text.
10. Creation 14(1):13, 1991. A fossil find in New South Wales in 1984 indicated the platypus was once a larger animal, with teeth. That find is consistent with other indications that the platypus today has lost information possessed by its more robust ancestor (see box above). Return to text.