In celebration of their 20th anniversary, our friends at Mental Floss share a look back at some of the fascinating animals science has discovered in the past two decades.
Twenty years ago, the first-ever issue of Mental Floss hit newsstands. Over those two decades, scores of creatures that were once unknown to mainstream science finally came to light. From purring monkeys to the “wandering leg sausage,” here are 20 amazing animals the wider world has been introduced to in the last two decades.
1. The Olinguito (Bassaricyon neblina)
Dogs, cats, seals, and raccoons all belong to the mammal order Carnivora. When biologists first identified the olinguito, an orange-brown raccoon relative, in 2013, it became the first new member of that group to be discovered in the Americas since 1978. Olinguito specimens had actually been lying around museums for decades before someone identified them as a distinct species. Native to the cloud forests of Ecuador and Columbia, the olinguito weighs about two pounds and has an omnivorous diet.
2. Six-Gill Sawsharks (Pliotrema kajae and Pliotrema annae)
Sawsharks are named for their long snouts adorned with a comb-like set of teeth. Researchers collected two new species from the Indian Ocean in 2020: Pliotrema kajae and Pliotrema annae. Unlike most sawsharks, which have five gills per side, both species have six gills on both sides of their bodies.
3. The Bald Parrot (Pionopsitta aurantiocephala)
Unlike the bald eagle, the South American bald parrot's face and neck are quite literally naked. Ornithologists were surprised to learn about this bizarre, bald bird, which boasts a vividly orange head, in 2002. Though only one parrot was seen, because its distinct lack of head feathers, scientists were sure it was a previously unknown species.
4. Lady Gaga’s Treehopper (Kaikaia gaga)
Treehoppers are noted for making music with vegetation and eating plant juices, and when University of Illinois grad student Brendan Morris named a new species of the insect in 2020, he decided to honor the iconic pop star Lady Gaga. “If there is going to be a Lady Gaga bug, it’s going to be a treehopper, because they’ve got these crazy horns, they have this wacky fashion sense about them,” he said in a press release.
5. The Vangunu Giant Rat (Uromys vika)
Locals were already aware of a large, coconut-eating rat that prowled Vangunu Island (of the Solomon Islands) when mammologist Tyrone Lavery confirmed its existence in 2015. "It's the first rat discovered in 80 years from Solomons, and it's not like people haven't been trying—it was just so hard to find," Lavery said in a press release. At 18 inches long and 2.2 pounds—four times heavier than your typical sewer rat—the rodent is big enough to make Carey Elwes do a double-take.
6. The Pygmy Three-Toed Sloth (Bradypus pygmaeus)
File this one under the “hiding in plain sight” category. Isla Escudo de Veraguas is a tiny island—a mere 1.6 square miles in size—off the coast of Panama. Just like the mainland, it has a resident population of three-toed sloths. But those living on the island are smaller by comparison, and in 2001, they were formally recognized as belonging to their own distinct species.
7. A Shiny Snake (Achalinus zugorum)
8. Goodman’s Mouse Lemur (Microcebus lehilahytsara)
True to its name, this big-eyed lemur isn’t much larger than a typical mouse. Restricted to the rainforests of eastern Madagascar, Goodman’s mouse lemur made international headlines when its discovery was first announced in 2005. The creature is nocturnal and often sleeps in huddled groups by day.
9. Greening's Frog (Corythomantis greening)
Poisons are toxins that take effect when they’re swallowed, inhaled, or absorbed through the skin. On the other hand, venom has to be injected into the target (think fangs and stingers). Although poisonous frogs are common, the first venomous species, Greening's frog, wasn’t documented until 2015 in Brazil. (Scientists had been aware of Greening's frog earlier, but they didn't know the predator-less amphibian was venomous.) When a scientist picked up the long-faced amphibian, it scraped his hand with spines hidden on the upper jaw, which released a chemical cocktail that was excruciatingly painful. And the venom doesn't just hurt—it's also twice as toxic as a pit viper's.
10. Northern Sierra Madre Forest Monitor (Varanus bitatawa)
The Komodo dragon isn’t just the biggest lizard alive today, it’s also the world’s most famous monitor. Generally, monitor lizards—which are known for their forked tongues—eat meat, insects, and eggs. But not the Northern Sierra Madre forest monitor, which scientists formally recognized in 2010. These 6.5-foot tree-climbers specialize in eating fruit.
11. The “Few-Toothed Mouse” (Paucidentomys vermidax)
In 2012, researchers described a shrew rat from the Island of Sulawesi that—unlike other rodents—doesn’t have molars, and would be totally toothless if it weren’t for a set of double-pointed incisors, also unique to the rodent. Experts think it lives off earthworms; the latter part of its name translates to “worm devourer.”
12. The “Wandering Leg Sausage” (Crurifarcimen vagans)
Is it some kind of sentient hotdog, or perhaps a vagabond bratwurst? Nope—it's a 6-inch-long millipede. Restricted to the Eastern Arc Mountains of Tanzania and named in 2012, the creepy-crawly has a "fat, sausage-like shape" and is half an inch in diameter. It comes with 112 pairs of legs.
13. The (Zospeum tholussum)
This cave-dwelling mollusk lives about 3000 feet below the surface of Croatia in total darkness. Not only does it lack eyeballs, but both its body and its shell are translucent. “Snails normally use pigment to hide, to protect themselves, or to mate,” zoologist Alexander Weigand, who described the species in 2013, told Science Friday. But when you're in the dark, neither potential mate nor foe can see you, so pigmentation isn't necessary.
14. The Eastern Santa Cruz Tortoise (Chelonoidis donfaustoi)
Genetic testing revealed in 2015 that two giant tortoise populations found on opposite ends of Santa Cruz Island in the Galápagos are actually different species. Previously, they were both classified as Chelonoidis porter, or “Santa Cruz tortoises.” To set them apart, scientists gave the reptiles on the island’s eastern side an all-new species name.
15. The White-Spotted Pufferfish (Torquigener albomaculosus)
They looked like something out of M. Night Shyamalan’s Signs. In 1995, off the coast of Japan, divers started noticing wavy, circular patterns, each about 6 feet wide, decorating the ocean floor. Something must have left these behind in the sand, but what? We got our answer in 2013. Spoiler alert: The aquatic “crop circles” (as news outlets called them) are made by the males of a previously unknown pufferfish species as part of an undersea mating ritual.
16. The Myanmar Snub-Nosed monkey (Rhinopithecus strykeri)
Ah, 2010: The year of shake weights, Four Loko bans, and ... snub-nosed monkeys? Rhinopithecus strykeri, a simian that mainstream scientists discovered in Myanmar that year, has an upturned nose and is rumored to start sneezing when raindrops hit it in the face.
17. A “Deep-Sea Blob” (Duobrachium sparksae)
Comb jellies are tentacled marine invertebrates that use rows of shimmering plates to travel through the water, and in 2015, footage taken in an Atlantic deep-sea canyon—over 12,700 feet below the surface—revealed a never-before-seen species, the first time a new species was identified using just high-definition video. "It moved like a hot air balloon attached to the seafloor on two lines, maintaining a specific altitude above the seafloor,” Mike Ford of the National Oceanic and Atmospheric Administration said in 2020. “Whether it’s attached to the seabed, we’re not sure. We did not observe direct attachment during the dive, but it seems like the organism touches the seafloor.” He called the creature “a beautiful and unique organism.”
18. The Pinocchio Frog (Litoria pinocchio)
Scientifically described for the first time in 2019, this New Guinea frog has a long protuberance anchored by the nostrils, which male frogs can either hold firm or let dangle. Herpetologists aren’t sure what it's for, but think it could help the males attract mates—or help the frogs differentiate themselves from other species.
19. The Tapanuli Orangutan (Pongo tapanuliensis)
Primatologists used to think there were only two living species of orangutan: The Bornean orangutan (Pongo pygmaeus) and the Sumatran orangutan (Pongo abelii). But in 2017, the population of orangutans living in the South Tapanuli region of Sumatra—which became geographically isolated for 10,000 to 20,000 years, and evolved to be genetically distinct from the other two species—were reclassified as a separate species. Thanks to their long period of isolation, the apes have some unique anatomical features, including smaller skulls and narrower eye sockets.
20. The Caquetá Titi (Plecturocebus caquetensis)
There were 441 new species found in the Amazon between 2010 and 2013 alone. One of them was the Caquetá Titi, a red-bearded monkey that will give you cuteness overload—in fact, when they feel contented, they're known to make purring sounds.
A version of this article was originally published on Mental Floss as "20 Amazing Animals Discovered in the Last 20 Years." Read more from Mental Floss.