In Sherlock Holmes' creator Arthur Conan Doyle's 1912 work, The Lost World, a group of explorers travel to an isolated plateau in the Amazon where animals long thought to be extinct still roamed.
What is the Lazarus Effect?
What if that were true? What if we could really see animals known only from their fossils, alive and walking the earth? In 1983, paleontologists Karl Flessa and David Jablonski coined the term Lazarus Taxa for just that scenario, named for the biblical Lazarus of Bethany who is described in the Gospel of John as having risen from the dead.
It turns out that several seemingly extinct animals really have returned from the dead.
By 1938, the fossil record was full of specimens of an extinct fish known as the coelacanth. The fish, who lived between 360 million and 65 million years ago, was thought to have gone extinct during the Cretaceous–Paleogene extinction event.
Scientists knew from the fossils that the extinct fish was enormous, over six feet in length, and weighing around 200 pounds. Then, something extraordinary happened. On December 23, 1938, fishermen off the coast of South Africa pulled aboard an unusual fish, and the captain alerted his friend, Marjorie Courtenay-Latimer.
Courtenay-Latimer was curator of the East London Museum in South Africa, and as soon as she saw the fish, she began an effort to preserve it despite South Africa's hot summer, an effort she ultimately lost.
Courtenay-Latimer was, however, able to send sketches of the fish to Rhodes University ichthyologist J.L.B. Smith. Smith recognized the fleshy fins that appeared almost like arms and legs as those of a coelacanth, and he named the fish after Courtenay-Latimer and published the astonishing findings in the journal Nature.
Between 1938 and 1975, off the east coast of East Africa 84 separate specimens of what became known as Latimeria chalumnae, or the West Indian Ocean coelacanth, were discovered.
Fast forward to September 1997, when marine conservationist Dr. Mark Erdmann and his wife were visiting a fish market in North Sulawesi, Indonesia. Noticing an odd specimen, Erdmann took several photos, and it wasn't long before the fish was identified as a unique species of coelacanth, Latimeria menadoensis, or the Indonesian coelacanth.
Erdmann encouraged local fishermen to be on the lookout for more specimens, and in July 1998, the first live specimen of Latimeria menadoensis was captured.
Coelacanths are remarkable for several reasons:
- They belong to the ancestors of tetrapods - four-legged, land-dwelling animals like us.
- Coelacanths have a unique form of locomotion — they have four fins which extend from their bodies like limbs, and which move in an alternating pattern identical to that of an animal's forelegs and hind legs.
- Unlike any other living animal, the coelacanth has a hinge in its skull, known as an intracranial joint, that allows it to open its mouth extremely widely which enables it to consume large prey.
- Coelacanths don't have a backbone, instead, they have an oil-filled notochord which is a hollow, pressurized tube; in most other vertebrates, the notochord is replaced during development in the womb by a vertebral column.
- Coelacanths have a rostral organ in their snouts that act like an electrosensory system, allowing them to use electroreception to detect prey.
Coelacanths are nocturnal, resting in caves and crevices during the day, then emerging in the late afternoon. Then, they drift along the ocean bottom, traveling as much as five miles (eight kilometers) in a single night.
Coelacanths often group together in the same cave or crevice, and they show no aggression towards one another. Not the most attractive fish, coelacanths also don't taste very good. Their flesh contains high amounts of oil, urea, and wax esters, and their scales ooze large quantities of mucus.
It is thought that coelacanths have a particularly long gestation period of up to three years, after which they give birth to live young.
2. The Bush Dog
1842, Danish naturalist Peter Wilhelm Lund described an extinct taxon of animal-based fossils he had found in Brazilian caves. The following year, Lund described living specimens he called bush dogs, never realizing that the two were one and the same.
Today, the bush dog is the only living species in the genus Speothos whose closest living relative is the African wild dog. Adults are 22 to 30 inches (57–75 cm) long, with five to 6-inch-long (12.5–15 cm) long tails. They stand 8 to 12 inches (20–30 cm) at the shoulder and weigh around 13 pounds.
Bush dogs can be found from Costa Rica in Central America, down through South America east of the Andes. They are carnivores who hunt during the day, primarily hunting pacas, agouti, capybaras, and even the much larger tapir. They hunt cooperatively in packs.
3. False Killer Whale
Based on a skull discovered in 1843, the False Killer Whale, Pseudorca crassidens, was first described in 1846 by the British paleontologist Richard Owen in his book, A History of British Fossil Mammals and Birds.
The skull was found in Stamford, Lincolnshire, UK and dated to 126,000 years ago. The animal was thought to be extinct until 1861, when carcasses washed up in Denmark and an entire pod beached itself. The next year, the species was moved to the newly-created genus Pseudorca which reflected its being neither a porpoise nor a killer whale.
False Killer Whales are most closely related to Risso's dolphin, the melon-headed whale (Peponocephala electra), the pygmy killer whale (Feresa attenuata), and the pilot whale (Globicephala spp.).
Among the largest of the dolphins, the False Killer Whale is 20 feet (6 m) long, and weighs up to 4,900 lbs (2,200 kg). It is a gregarious animal who interacts with bottlenose dolphins and pilot whales, and can even mate with them, producing what are known as "wholphins".
False Killer Whales travel in large pods of up to 500 members, and remain within their pods for most of their lives. They are found in tropical and semitropical ocean water, and are rarely found above 50 ° N or below 50 ° S.
False Killer Whales have been known to offer fish to humans who are diving or on boats, but they have also been known to steal fish off hooks. In November 2012, the National Oceanic and Atmospheric Administration (NOAA) declared the Hawaiian population of False Killer Whales, comprising some 150 individuals, as endangered.
4. Laotian Rock Rat
In 1996, researchers from the Wildlife Conservation Society were visiting a meat market in Thakhek, Khammouan, Laos when they spotted an odd-looking, squirrel-like rodent. By 1998, local villagers had found three additional dead specimens.
A mashup of a rat and a squirrel, Laotian Rock Rats are dark grey with a blackish tail that is limp. They have a large head with round ears and very long whiskers. They are about 10 inches long (26 cm) with a 5.5 inch (14 cm) long tail.
On June 13, 2006, a professor emeritus from Florida State University and a Thai wildlife biologist announced that they had captured, photographed, and videotaped a live specimen of the species.
This caused the British zoologist Paulina Jenkins to propose that the animal be placed in an entirely new family, however, a vertebrate paleontologist at the Carnegie Museum of Natural History in Pittsburgh, Mary Dawson, argued that the rat belonged to the ancient fossil family Diatomyidae, which was thought to have been extinct for 11 million years.
5. Monito del Monte
This small marsupial, Dromiciops gliroides, is native to only Argentina and Chile and is the only living species of the ancient order Microbiotheria. It was first described by British zoologist Oldfield Thomas in 1894.
The Monito del Monte is an ancestor to Australian marsupials, likely due to the fact that Australia and South America were connected via Antarctica during the early Cenozoic Period.
Monito del Montes are 3 to 5 inches (8–13 cm) long, with a somewhat prehensile tail. Females have a fur-lined pouch with four teats, and the young remain in the pouch for around five months. After they emerge from the pouch, they will then ride on the mother's back.
The species is nocturnal and arboreal and feeds on insects, invertebrates, and fruit, especially the mistletoe fruit. The animal is the sole dispersal agent for this plant, with germination taking place in its gut. Scientists estimate that the relationship between the two species began 60 to 70 million years ago.
6. Chacoan Peccary
This animal, Catagonus wagneri, is the last existing species of the genus Catagonus, was first described in 1930 based on fossils, and was thought to be extinct. Then, in 1971, live animals were discovered in the Chaco region of Salta, Argentina.
The Chacoan Peccary is the largest of the three species of peccaries, and has many features similar to pigs. It differs from other species of peccary by having a third hind toe, while the other species only have two. It also has longer ears, snouts, and tails.
The animals live in herds of up to 20 individuals, and they are most active in the morning, feeding on various species of cacti. They use their snouts to roll cacti over the ground, rubbing off their spines.
The Chacoan peccary is vulnerable to human activity, and herd numbers are decreasing. Zoos in North America and Europe have established captive breeding programs.
7. Bulmer's Fruit Bat
In 1960, archaeologist Sue Bulmer was digging in caves in the western highlands of Papua New Guinea. On the menu for the cave dwellers 10,000 years ago were fruit bats, and Bulmer sent some specimens to a specialist at the University of Papua New Guinea, James Menzies.
One specimen had a strangely formed jaw and its wings were placed unusually on its back. Menzies realized it was a new species of bat that he named Aproteles bulmerae after Sue Bulmer.
Fast forward 14 years when anthropologist David Hyndman was studying the Wopkaimin people of Papua New Guinea. Hyndman accompanied them on a bat-hunting trip to the Luplupwintem cave, which is 2,300 meters above sea level, where they shot many bats.
Hyndman noticed that the bats appeared unusual, and after a tussle with one of the Wopkaimin's dogs over a bat carcass, Hyndman sent it along to an expert to be evaluated.
As luck would have it, that expert turned out to be James Menzies, and he realized that far from being extinct, the Bulmer's fruit bat was alive and well. However, during subsequent trips that Hyndman made to the cave in 1977 and 1985, no bats were found, and Hyndman feared the species had gone extinct once again.
Fascinated by the story of the Bulmer's fruit bat, paleontologist Tim Flannery began making trips to the area, and in 1992, upon entering the Luplupwintem cave, he was rewarded with the sight of over 100 Bulmer's fruit bats.
8. Thylacine and Woolly Mammoth
These animals' seeming return from the dead inspires us to dream that in some remote corner of Tasmania, the Thylacine, or Tasmanian Tiger, is still alive. The last one known died in an Australian zoo in 1936.
And, perhaps on some frozen steppe in Siberia, the Woolly Mammoth still roams.