The Pregnant Platypus With a Secret

Tuesday, January 4, 1944, was a momentous day in world history — well, if your world centers around the lives of platypuses, at least. Platypuses (like the one seen above) are a semi-aquatic mammal that looks kind of like fuzzy ducks that lay eggs and are native to Australia. And on that day in Melbourne, a platypus was born in captivity for the first time.

While the rest of the world didn’t really care, zoos everywhere were excited. With the notable exception of the San Diego Zoo, there aren’t any platypuses living in captivity outside of Australia, and the birth of this particular platypus gave zoo administrators hope of adding the creatures to their exhibits. On April 25, 1947, New York City’s Bronx Zoo received three platypuses from Australia — two females, named Penelope and Betty, and one male, named Cecil. Under the tutelage of a husband-wife team of platypus experts, the zoo built a platypusary — a platypus habitat — and hoped that Cecil would mate with one of the two females and build the first platypus family outside of Australia.

Their efforts got off to a rough start, Betty died shortly after arriving in the United States. As Time Magazine reported, “for outside Tasmania and Australia, these two furry mammals were the only platypuses in captivity, and everybody hoped that one day Cecil and Penelope would produce platykittens.” But it didn’t seem meant to be. Cecil was certainly willing — per Time, “he grabbed her flat tail in his duckbilled, toothless mouth, and held on for dear life while Penelope dragged him around the pool in slow circles. At times Cecil would let go and roll over and over in the water.” But the interest went unrequited: “Penelope, who after all weighs two pounds to Cecil’s four, did not see what there was to be so ecstatic about. She didn’t want Cecil around any more. Her tail hurt.” As of 1952, the two had spent five years together but were hardly a couple.

That seemed to change in 1953. That June, Penelope seemed open to Cecil and the two ended up spending more time together. Shortly thereafter, Penelope’s behavior changed. Time Magazine (in a different article than above — yes, Time wrote about Penelope the platypus more than once), summarized what was different:

When the curators provided her with eucalyptus leaves. Penelope took them into the burrow. Since wild platypuses make their breeding nests out of just such leaves, the curators grew hopeful.

On July 9 Penelope retired to her burrow and did not appear again for six days. She ate an enormous meal and popped back again. The curators hovered around, smiling at one another like fond godfathers. All the signs pointed to platypus eggs, perhaps even hairless platypus infants wriggling in the nest.

Eating for Two. Then came long and anxious waiting while the presumed young platypuses passed through the nursing stage. Penelope kept her own council, but she seemed to be eating for two or more. Huge quantities of worms and larvae disappeared into her duck bill. Her offspring were presumably demanding more and more milk.

The zookeepers estimated that Penelope’s babies would arrive in late October of that year, and the hatching of the little platypuses from their burrows attracted press from around the nation if not the world. But October gave way to November and no babies emerged. On November 2, 1953, zookeepers decided to force the issue, going into the burrow to retrieve the younglings. Roughly fifty reporters came to the Bronx Zoo in hopes of capturing photos of the first platypuses born in the United States — and all of them came away disappointed. As the New York Times reported (pdf), starting at 8:30 AM, “workers surrounded by excited and smiling officials started to sift the earthen bank,” but by 2:15 PM, they had given up: “every inch of soil in the 7- by 9-foot platypusary had been sifted” and nothing — no eggs, no nest, and no babies — had been found. Penelope, as the Times summarized in its headline, “[wasn’t] a mother after all, only a faker.”

She wasn’t done with her tricks. While she’d never get pregnant with Cecil (nor fake a pregnancy again), in 1957, she did something new — she vanished. One morning in late July of that year, zoo administrators woke up to discover that Penelope had, somehow, left the zoo. As Mental Floss explained, no one was sure how she escaped the platypusary — “she might have tunneled beneath part of its mesh border, found a crack to crawl through, or else climbed over the fence,” but there was no evidence suggesting one path versus the other (minus the absence of a tunnel). No one knows where she went; despite an exhaustive search and a lot of citizen reports of platypus sightings, she was never found. Why she left, though, was no secret; as Mental Floss further notes, “zookeepers were pretty sure they knew why she did it: Cecil had been relentlessly pursuing her to the point of harassment, going so far as to wriggle into her section of the enclosure even after they’d been separated.”

On September 17, 1957, officials gave up on their hunt for Penelope and, per the New York Times (pdf), declared her “presumed lost and probably dead.” Cecil, perhaps suffering from a broken heart, died the next day.

Bonus fact: If you happen to have an opportunity to visit some platypuses, avoid the male ones if it’s during mating season. Male platypuses are venomous and prone to attack if they think you’re coming between them and a potential mate. And while you’ll survive such an attack, the aftermath and recovery aren’t any fun. As Wikipedia’s editors explain, “[platypus venom] produces excruciating pain that may be intense enough to incapacitate a victim. Swelling rapidly develops around the entry wound and gradually spreads outward. Information obtained from case studies shows that the pain develops into a long-lasting hyperalgesia [that is, “an abnormally increased sensitivity to pain”] that can persist for months but usually lasts from a few days to a few weeks. A clinical report from 1992 showed that the severe pain was persistent and did not respond to morphine” or other known painkillers. Yikes!

From the Archives: Hairy Houdini: Another zoo escape artist.