For 62 years, the only proof that Attenborough’s long-beaked echidna ever existed was a single specimen, recovered in 1961 from the Cyclops Mountains of New Guinea. In the interim, this quill-covered, egg-laying mammal (named for the British naturalist David Attenborough) vanished from the scientific radar.
After all that time, you might think, it would’ve been perfectly reasonable to presume the creature extinct. But then, in 2007, an expedition stumbled upon evidence of its survival: “nose pokes” in the soft rainforest ground. Another decade and a half went by before researchers from Oxford University captured one on camera in November 2023. The echidna, as it turns out, still lives.
The species wasn’t extinct after all, but rather a “lost species” — one that’s gone unseen for years or decades, but that scientists haven’t given up on. So, how many lost species are there, and which are most intriguing — and most wanted — among scientists?
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How Many Lost Species Are There?
A study published in 2022 counted about 560 lost mammals, birds, amphibians, and reptiles. Just last month, a new study raised that number to more than 850. And when you add invertebrates, plants, and other forms of life, the total soars to 2,200 species, according to the conservation non-profit Re:wild.
Occasionally these stories have happy endings. Besides Attenborough’s long-beaked echidna, last year saw the reemergence of the De Winton’s golden mole from South Africa, which had been hiding out for nearly a century. And in 2023, the Brazilian pernambuco holly tree showed itself for the first time in 185 years — after keeping a profile so low that celebrities should be taking notes.
Still, under the looming threats of climate change and habitat destruction, the list of missing species is long and getting longer. Here are seven of the most sought-after species.
Read More: What Animals Are Going Extinct?
1. Blanco Blind Salamander (Eurycea robusta)
Last Seen: 1951
More than 70 years ago, while digging up the dry bed of the Blanco River in central Texas, gravel workers stumbled upon four of these translucent, eyeless salamanders. Apparently two were eaten by a passing heron, and one got lost, but the workers safely delivered the fourth to the University of Texas at Austin, where researchers identified it as a new species.
To this day, that single specimen is the only record we have of the Blanco blind salamander. The species is stygobitic, meaning it’s adapted to and spends its entire life in dark, water-filled, subterranean caverns. But the spring where the salamanders were originally found has since disappeared, and searches of nearby springs in 2006 and 2020 were unsuccessful.
2. Pondicherry Shark (Carcharhinus hemiodon)
Last Seen: Before 1960
The pondicherry shark, with a stout gray body growing to just three feet long, historically ranged from the Gulf of Oman to Southeast Asia. Fewer than 20 specimens have been retrieved and added to museum archives, all from before 1960 and most from around India. Most sharks can only tolerate saltwater, but this one is at home in rivers as well as the ocean.
There have been many reports of the species over the years, most notably in 2019, when the Discovery Channel’s “Shark Week” featured a purported sighting from a remote Sri Lankan fishing village. Nevertheless, in 2021, a study by the International Union for Conservation of Nature stated that none of these claims could be verified. Pondicherry sharks are nearly identical to juvenile bull sharks, leading to frequent misidentification.
Read More: Scientists Are Trying to Save These Animals From Extinction
3. Togo Mouse (Leimacomys buettneri)
Last Seen: 1890
Like the pernambuco holly, this nondescript rodent has somehow managed to evade scientific notice for more than a century. Only two specimens were ever collected, both in 1890, near the border between Ghana and Togo.
At this point, we’d have every right to call it a lost cause — except that locals and rangers at a national park near the site of its discovery seem to recognize images of the species, calling it “yefuli.” Two expeditions in the 1990s failed to locate any of them, however, and it will take more surveys to determine their status one way or another.
4. Ivory-Billed Woodpecker (Campephilus principalis)
Last Seen: 1944
Possibly the most coveted missing animal in North America, the ivory-billed woodpecker has been the subject of a continuous, decades-long search by amateur birders and professional ornithologists alike. No wonder why — it earned the nickname “Lord God bird,” since those were typically the first words to escape the mouths of anyone seeing its stately form for the first time.
As its habitat (old-growth southeastern swampland) disappeared in the logging spree of the early 20th century, the ivory-billed woodpecker went with it. But plenty of unverified reports have cropped up in the eight decades since the last universally accepted sighting, including a much-publicized study last summer that included grainy video and camera footage.
The evidence is ambiguous enough that, in October, the U.S. Fish and Wildlife Service decided to hold off on declaring the bird extinct, leaving it on the list of endangered species — and leaving its many admirers with a flicker of hope.
5. Bull-Neck Seahorse (Hippocampus minotaur)
Last Seen: 1996
Little is known about this pygmy seahorse, since it hasn’t been seen since its discovery. The only known specimens were collected off Australia’s southeastern coast near Eden. Its name (which translates to the outstanding scientific binomial Hippocampus minotaur) comes from its thick neck and large head-to-body ratio — just like the mythical minotaur, with the head of a bull and the body of a human.
The species is thought to live (if it is still living) in sand beds up to 300 feet below the ocean surface, and possibly in Gorgonian corals, where it may wrap its graceful, prehensile tail around the underwater structures. It could be one of the more difficult lost species to rediscover, since surveys would require trained deep-sea divers.
Read More: 5 Plants and Animals that Are Endangered in 2023
6. Banded Trinity (Thismia americana)
Last Seen: 1916
Everything about this plant is baffling. A seemingly out-of-place member of a genus found mainly in the tropics, banded trinity was first spotted on the prairie of southern Chicago in 1912, only to suddenly go missing four years later. What’s more, it’s a saprophyte — a plant without leaves, stems or roots, that draws energy from decaying plant matter rather than the sun.
In the early 1990s, a team of botanists identified 22 sites as likely Thismia habitat and recruited volunteers to hunt for them four summers in a row. To test the odds of uncovering such small, nondescript flowers, they scattered look-alike white beads throughout the grass; the hordes who joined the search didn’t find a single one.
7. Miss Waldron’s Red Colobus (Piliocolobus waldronae)
Last Seen: 1978
This West African monkey was, for a time, the first primate declared extinct in centuries. In 2000, around 22 years after the last official sighting, scientists deemed Miss Waldron’s red colobus (named for a member of the expedition that discovered it in 1933) a goner.
A year later, in 2001, primatologists received a tail from a hunter in the southeast corner of Côte d’Ivoire. The next year they received a bit of reddish skin. Both appeared to be from the supposedly extinct red colobus, and based on this evidence, some biologists believe a small population may be clinging to survival in the forest around Ehy Lagoon, on the Atlantic Coast. That said, surveys have yet to turn up any living individuals.
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