Platypus

When explorers brought the first platypus specimen to England in the late 18th century, scientists believed it was a hoax. And understandably so. The long, duck-like bill, webbed feet, and fur resembling an otter’s made it seem like an animal patched together from other creatures—more jackalope than science. “It naturally excites the idea of some deceptive preparation by artificial means,” zoologist George Shaw wrote in 1799. And it wasn’t until almost a century later that scientists discovered that platypuses lay eggs.

On a genetic level, the platypus has been assembled from bits and pieces of different classes. The species still intrigues modern researchers, both as a potential, if unlikely, source of medical breakthroughs, and as an animal that may fall victim to climate change. Let’s see what fits the bill.

0.7–2.4 kg (1.5–5.3 lb): Weight range

50 cm (20 in): Average length of a male

43 cm (17 in): Average length of female

>3 ft (0.9 m): Length of prehistoric platypuses

31.3 seconds: Mean dive time for food foraging

12.4 hours: Continuous foraging activity platypuses require to eat each day

20 m (66 ft): Length of the burrows female platypuses dig for their eggs

10-12 days: Time eggs are incubated in the burrow

30%: Extra energy platypuses exert on land compared to similar-sized mammals

73%: Projected population decline for platypuses in the next 50 years due to territory loss and climate change

The platypus has stumped scientists for centuries, and there have been new discoveries about its genetic makeup in the last decade. While it is a mammal, it shares genes with reptiles and birds, and is something of a hybrid between these animal classes, posing questions and offering up answers about the evolutionary process.

Its hybrid qualities are more than skin deep: Like a bird, it lays eggs. Platypuses are one of the only living monotremes, or egg-laying mammals, left on the planet—it’s just them and four species of the equally odd echidna, or spiny anteater, perhaps a remnant of their ancestors’ affinity for water. Like echidnas, they’re also venomous, one of 12 such mammals. Precious few humans have been poisoned by a platypus, and the results are resistant to morphine, “long-lasting and excruciating” (we’re talking weeks), but not fatal.

And it’s not just eggs that make these mammals so odd. They have a single duct for urine, feces, and reproduction, which is why they’re classified as monotremes (literally “single hole”), as well as legs on the sides rather than underneath the body, which are reptilian qualities. The males also have internal testes, another characteristic found in reptiles.

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“I like the duck-billed platypus

Because it is anomalous.

I like the way it raises its family,

Partly birdly, partly mammaly.”

—American poet Ogden Nash

120 million years ago: Monotremes split from other mammals.

100,000 years ago: Date of the earliest modern platypus fossil.

1797: Captain John Hunter sees a platypus speared in Yarramundi Lagoon just north of Sydney, Australia, one of the first documented encounters with the mammal.

1799: George Shaw, keeper of the Department of Natural History of the Modern Curiosities of the British Museum, publishes the scientific name Platypus anatinus for the mammal in Naturalist’s Miscellany.

1800: Johann Blumenbach separately describes the platypus as Ornithorhynchus paradoxus in Abbildungen naturhistorischer Gegenstande. This becomes the official scientific name for the species.

1884: While on an expedition in Australia, William Hay Caldwell discovers that platypuses are oviparous—the female platypus lays eggs.

1937: The platypus is featured on the 9d Australian stamp, the first time (and nowhere near the last) it appears on a stamp.

1939: National Geographic publishes an article on the platypus.

1966: An embossed image of the platypus is featured on the Australian 20-cent coin, and where it still appears.

2000: The platypus is one of three mascots chosen for the Sydney Summer Olympics.

2005: Researchers at Australian National University discover platypuses have 10 sex chromosomes.

2008: In a close study of platypus DNA, scientists determine that it shares genes with reptiles, birds, and mammals.

2019: A pair of platypuses live in captivity at the San Diego Zoo Safari Park, the only place outside of Australia where they have successfully lived.

2020: Researchers at the University of New South Wales share evidence that platypuses are at risk of becoming extinct, due to water resource development, land clearing, climate change, as well as severe drought periods causing wildfires.

Platypuses have something like a sixth sense in their bills, which consists of thousands of cells that allow them to detect the electric fields generated by all living creatures. This electrolocation enables platypuses to hunt without using their eyes, ears, and nose.

National Geographic follows researchers as they track down platypuses and extract their DNA to better understand their evolution and determine if there are genetic differences between the northern and southern platypuses in Australia, which would mean there could be a separate subspecies.

Female platypuses feed their young milk, but from sweat-like mammary glands instead of nipples. There is an antibacterial protein in the milk to keep it safe for the offspring, even when it is exposed to potential contaminants. This protein has a unique structure that is being studied for its potential to help develop new antibiotics for humans (as is komodo-dragon blood).

And it’s not just female platypuses that can provide critical medical aid for humans. The venomous spurs on the heels of males’ hind feet have a poison that contains GLP-1 (glucagon-like peptide-1), a hormone known to treat diabetes. GLP-1 is also found in humans and other mammals to promote insulin release, but is short-lived and degrades quickly, appearing to last longer in platypus venom.

A too-cute-to-be true photo of a baby platypus broke the internet recently, first as it made the social media rounds and then when it was revealed to be fake. The figurine was made by Serbian fantasy artist Vladimir Matić-Kuriljov, who sculpts with the plastic-like polymer clay Super Sculpey. He’s made other animal sculptures, including a miniature walrus.

Platypuses are pretty weird, right? They probably don’t think so, though. They are “in many ways more akin to the original mammal blueprint than the rest of us,” writes Elsa Panciroli in The Guardian. Egg laying, venom, and cloaca may have all been features of the very earliest mammals. Monotremes went their own way before the placenta evolved, making them “somewhere between a lizard and what we think of as a human-like placental mammal,” biologist Rebecca Young tells National Geographic. (The placenta itself is pretty weird, and no less amazing than a venomous, egg-laying mammal.)

Platypus venom features 83 different toxin genes, “some of whose products closely resemble proteins from spiders, sea stars, anemones, snakes, fish, and lizards, as if someone cut and pasted genes from the entire diversity of venomous life into the platypus’s genome,” Mindy Weisberger writes on Live Science. It’s believed to be an example of convergent evolution, a process where different animals evolve similar traits independently.