10 of the Weirdest Extinct Animals You’ve Never Heard Of

While many of us are familiar with the tragic stories of the dodo bird, passenger pigeon, and Tasmanian tiger, there are countless lesser-known creatures that have vanished from our planet. 

Here are 10 of the weirdest extinct animals you’ve never heard of, and the fascinating tales behind their demise. 

1. The Koala Lemur: A Gentle Giant

10 of the Weirdest Extinct Animals You've Never Heard Of - Koala Lemur wc
Image Credit: FunkMonk (Michael B. H.), CC BY-SA 3.0, via Wikimedia Commons

Imagine a lemur the size of a gorilla with a skull to match. That’s the koala lemur (Megaladapis edwardsi), a gentle giant that once roamed the island of Madagascar. Growing up to 5 feet long and weighing around 165 pounds, this slow-moving primate was well-adapted for a life in the trees, with long arms and a diet of leaves.

Sadly, the arrival of humans on Madagascar spelled doom for the koala lemur. Hunting and habitat destruction drove this species to extinction around 500 years ago, along with at least 16 other lemur species.

2. The Alien Goldfish from Outer Space?

10 of the Weirdest Extinct Animals You've Never Heard Of - Fossil of Typhloesus wellsi wc
Image Credit: Ghedoghedo, CC BY-SA 3.0, via Wikimedia Commons

When paleontologist Simon Conway Morris first laid eyes on the fossils of Typhloesus wellsi, he jokingly nicknamed them “alien goldfish,” speculating that they could have been the discarded pets of a visiting intergalactic traveler. (ref) While their true origins are decidedly more terrestrial, these Carboniferous-period creatures were no less bizarre.

T. wellsi had a unique feeding strategy, shooting a toothy “tongue” out of its gut to catch unsuspecting prey. Some researchers believe this strange animal may have been an early relative of modern gastropods.

3. The Sea Monster with a Boomerang Skull

10 of the Weirdest Extinct Animals You've Never Heard Of - Diplocaulus magnicornis fossil wc
Image Credit: Donarreiskoffer, CC BY-SA 4.0, via Wikimedia Commons

The Permian-period amphibian Diplocaulus magnicornis is instantly recognizable by its boomerang-shaped skull. While the function of this unusual cranial arrangement remains a mystery, paleontologists suspect it played a role in how the animal swam.

Fossils of D. magnicornis have been found in what is now Texas, providing a glimpse into the strange aquatic life that thrived around 275 million years ago.

4. The Mighty Worm of Metal

10 of the Weirdest Extinct Animals You've Never Heard Of - Websteroprion armstrongi wc
Image Credit: Mats E. Eriksson, Luke A. Parry & David M. Rudkin, CC BY 4.0, via Wikimedia Commons

Named after death-metal guitarist Alex Webster, Websteroprion armstrongi was a formidable marine worm that terrorized the Devonian seas. Growing up to 6.6 feet long, this giant carnivore was the largest known species of its kind, dwarfing its modern relatives.

When W. armstrongi was first described in 2017, it immediately claimed the title of the largest marine jawed worm on record, (ref) a fitting tribute to its namesake’s musical prowess.

5. The Deer That Vanished in Plain Sight

10 of the Weirdest Extinct Animals You've Never Heard Of - Schomburgks deer wc
Image Credit: Lothar Schlawe, Public domain, via Wikimedia Commons

The Schomburgk’s deer ( Rucervus schomburgki) once roamed the grasslands of Thailand in large numbers. Named after the British consul in Bangkok who first described the species in 1863, this deer was hunted to extinction for its antlers, which were believed to possess magical healing properties.

During floods, the Schomburgk’s deer would gather on high ground, making them easy targets for hunters in boats. The last confirmed sighting of this species was in the 1930s, although some hold out hope that it may still survive in remote areas.

6. The Snake That Ate Crocodiles for Breakfast

10 of the Weirdest Extinct Animals You've Never Heard Of - Wonambi naracoortensis vs Thylacoleo wc
Image Credit: Alpha from Melbourne, Australia, CC BY-SA 2.0, via Wikimedia Commons

The extinct Australian python Wonambi naracoortensis was a force to be reckoned with. Measuring over 15 feet long, this non-venomous constrictor had recurved teeth and a diet that likely included crocodiles.

While most estimates place the extinction of W. naracoortensis around 40,000 years ago, some researchers believe it may have survived until as recently as 7,000 years ago. Its disappearance may be linked to the arrival of humans in Australia and the changes they brought to the landscape.

7. The Toothy Terror Bird of Texas

10 of the Weirdest Extinct Animals You've Never Heard Of - Titanis walleri ss2415286771
Image Credit: Mykola59/Shutterstock

Standing nearly 10 feet tall, Titanis walleri was one of the largest carnivorous birds to ever walk the Earth. This flightless “terror bird” had a powerful beak and could likely run at speeds up to 30 mph, making it a formidable predator in its North American habitat.

T. walleri is known from fossils discovered in Texas and Florida, where it lived during the Pliocene epoch, between 5.3 and 1.8 million years ago. Despite its fearsome reputation, this bird was no match for the changing climate and competition from mammalian predators.

8. The Reptile with a Double-Decker Wingspan

10 of the Weirdest Extinct Animals You've Never Heard Of -
Image Credit: Dmitry Bogdanov, CC BY 3.0, via Wikimedia Commons

Sharovipteryx, a small reptile from the Triassic period, may hold clues to the evolution of flight in pterosaurs. Measuring just one foot long, this unusual creature had four wing-like appendages – two short forelimbs and two longer hindlimbs – which were connected by thin flaps of skin.

Some paleontologists believe Sharovipteryx used its unique anatomy to glide (ref) from tree to tree in the forests of the supercontinent Pangea. While not a true pterosaur, this reptile provides a fascinating glimpse into the early experimentation with aerial locomotion.

9. The Pig-Faced Reptile with a Cheesy Grin

10 of the Weirdest Extinct Animals You've Never Heard Of - Casea wc
Image Credit: Compiled by Jesse Earl Hyde, various authors, Williston, Public domain, via Wikimedia Commons

With its massive, pig-like body, tiny head, and toothless lower jaw, Casea looked like something out of a cartoon. This bizarre reptile, whose name means “cheesy,” lived during the late Permian period and could grow up to 4 feet long.

Casea had an overhanging upper jaw with peg-like teeth, which it likely used to munch on tough vegetation. Its large ribcage suggests that it may have had a complex digestive system to process its plant-based diet.

10. The Unicorn of the Mongolian Plains

10 of the Weirdest Extinct Animals You've Never Heard Of - pronghorn dp104605018
Image Credit: twildlife/Deposit Photos

Tsaidamotherium, a pronghorn-like creature from the late Tertiary period, bore a striking resemblance to the mythical unicorn. This grazing animal had a large, cylindrical horn on its forehead, accompanied by a smaller horn just behind it.

It roamed the Mongolian plains alongside other Miocene herbivores, leaving behind tantalizing clues about its unique appearance and behavior.

davin
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Davin is a jack-of-all-trades but has professional training and experience in various home and garden subjects. He leans on other experts when needed and edits and fact-checks all articles.