The last of their kind
Fossils of extinct creatures elicit daydreams - seeing dinosaurs walk the Earth, watching the first birds take flight or observing a trilobite scurry through a tide pool.
Other than the remote hope of cloning extinct animals, these ponderings are reserved for the imagination. Extinction is the reason we should cherish the creatures that still roam the planet, the ones we still have a chance to experience. This is especially true when it comes to creatures teetering on the brink of extinction.
Photo: Wikimedia and Efired/Shutterstock
With this in mind, we present the world's rarest animals - species with fewer than 10 confirmed individuals left alive, including the Rabbs' fringe-limbed treefrog (above left) and the pygmy tarsier (right). (Text: Bryan Nelson)
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1. Red-crested tree rat
This adorable rodent - only known because of the existence of two specimens captured in Colombia in 1898 - hadn't been seen for over a century and was feared extinct. That is until one simply ambled up to a pair of biologists in May 2011 while they were camping in the field. The creature even stuck around for a photo shoot before wandering back into the dark forest.
Distinctive for a fiery-red patch of fur on its head, the red-crested tree rat is as cute as it gets. One can only hope that it will not disappear again for another 100 years.
It's impossible to say from this single finding how many individuals exist, but given that extensive searches for the animal have turned up nothing until now, it's safe to say that it's extremely rare. Where there's one, there are probably others.
Related Link: Endangered species: Where are they now?
2. Northern white rhinoceros
Several species of rhinoceros are critically endangered, but none is on its last legs like the northern white. These magnificent beasts once roamed vast territories in sub-Saharan Africa, but their numbers have rapidly declined over the last century, mostly due to poaching.
Their population in the wild was reduced from 500 in the 1970s down to just four in recent years. Unfortunately, not even these last four could find protection; they have vanished and it is now believed that poachers got to them as well.
This means that the only northern white rhinos still alive are the seven held in captivity. Two of them live at the San Diego Zoo's Safari Park, one resides at the Dvůr Králové Zoo in the Czech Republic, and four are part of a captive breeding program at the Ol Pejeta Conservancy in Kenya, in a last-ditch effort to revive the species.
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3. Rabbs' fringe-limbed treefrog
This charismatic little frog may truly be the loneliest creature on Earth: only one specimen is known to exist in the world, at the Atlanta Botanical Garden in Georgia [USA]. It is the latest species to fall victim to the devastating chytrid fungus, an infectious disease of amphibians believed to be the principle reason for the sharp decline in amphibian biodiversity around the world.
The Atlanta specimen previously had a companion - a male at Zoo Atlanta - until it had to be euthanized in 2012 after its health began to fail. The last known recording of the species in the wild was in 2007. The region where it was heard later became infested with the chytrid fungus, and the frog's characteristic croaks haven't been heard since.
The Rabbs' fringe-limbed treefrog is easily recognized by its chirp, which it uses to woo females. Unfortunately for the lone male, its chimes are now forever destined to go unrequited.
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4. Yangtze giant softshell turtle
The Yangtze giant softshell turtle is the largest freshwater turtle in the world. Unfortunately, it is also the world's rarest. Only four specimens are known to exist in the world: two inhabit separate lakes in Vietnam, and two others reside at Suzhou Zoo in China. Only one of the four is female, meaning that the survival of the species rests entirely on her capacity to breed.
Luckily, the female is one of the two specimens living at the Suzhou Zoo, and she has successfully mated with the resident male. However, so far none of the fertilized eggs has survived long enough to hatch. Scientists are working to improve conditions at the enclosure to improve the odds that a brood will survive.
The species was once widespread throughout the Yangtze River network in China, but eventually fell victim to widespread pollution, development and hunting.
Related Link: Sandy disrupted sea turtle nesting boom
5. Pygmy tarsier
Photo: Perrenque/Flickr
These miniature primates, which might be confused with mogwai, were believed to have gone extinct in the early 20th century until Indonesian scientists accidentally killed one while trapping rats. This find prompted an eight-year research expedition to rediscover the species, an effort that finally bore fruit in 2008. Researchers from Texas A&M University successfully trapped three pygmy tarsiers, two males and a female, and attached them with tracking collars. A fourth specimen was also spotted, but it got away.
Although no other specimens have been found since, scientists hope the species survives in some capacity, given that both males and the female were of breeding age.
6. Pinta Island tortoise
Tragic news came in 2012 when Lonesome George, the last known surviving Pinta Island tortoise, met his end. George had become a symbol of the need for enhanced conservation efforts in the Galapagos Islands, where the species originated. Once widespread across Pinta Island, the species eventually became imperilled after years of being hunted for meat. Goats that were introduced to the island in 1958 ate much of the vegetation, and the species was believed to have vanished from the wild.
Surprising new research on tortoises from nearby Isabella Island could offer a glimmer of hope for the species, however. Genetic evidence revealed at least 17 first-generation Pinta Island tortoise hybrids living there. These hybrids have one full-blooded Pinta Island tortoise parent, raising the possibility that at least one of the species is still roaming the island and breeding. Lonesome George may not have been the last of his kind after all.
Scientists plan to survey the island's tortoise population in the hopes of locating this rugged survivor. Even if no survivor is found, it may also be possible to breed the species back into existence by mating the first-generation hybrids.
Related Link: Galapagos to poison 180 million rats
7. Hula painted frog
Previously found only in the Lake Hula marshes of Israel before the lakes were drained to make way for farmland, these colourful frogs were believed extinct until one specimen was found during a routine patrol in the Hula nature reserve. The discovery boosted search efforts, which later turned up 10 more specimens.
More water was diverted to revive the marshes of the reserve, which is credited with the species' re-emergence. While the discoveries have been exciting, they are also only preliminary. It's still a very small population, and the frog has a long way to go before it can be considered a conservation success story.
Related Link: Once-extinct toads reintroduced to wild
8. Baiji dolphin
The Baiji river dolphin, which once swam extensively throughout the Yangtze River system, became the first cetacean species to be declared functionally extinct in modern times after an extensive six-week survey of the animal's habitat in 2006 turned up no sign of the species.
Then, just a year later, a Chinese man videotaped a dolphin gleefully leaping from the surface of the Yangtze, which experts later confirmed was indeed a Baiji dolphin. It's impossible to say how many of these dolphins still swim in the river, but it's certainly possible, given the rarity of the sighting, that this dolphin was the last of its kind.
Unfortunately, even if several individuals still cling to existence, experts says the species should still be considered functionally extinct, since such a small population would not be genetically viable. But so long as sightings occur, there's hope.
Related Link: 10 odd ways we protect endangered species
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