The Amazing Survival of a Diabolical Fish
The impish little Devils Hole pupfish has pulled a fast one -- evolutionarily speaking.
The critically endangered Devils Hole pupfish of Death Valley have long been considered the struggling survivors of the end of the last ice age 13,000 years ago – trapped in an dwindling watering hole in the midst of the most hellish desert on Earth.
But a new genetic analysis confirms that the fish known to science as Cyprinodon diabolis has managed the diabolically impossible: it seems to have arrived at Devil's Hole more recently and somehow mixed with other pupfish species of other desert springs within the last few centuries.
This apparently miraculous feat, while being very mysterious in itself, could actually demystify another inexplicable fact about the Devil's Hole minions that has long bedeviled scientists: how such a small population of fish living in a body of water the length and width of a couple of school buses could have survived for thousands of years without succumbing to inbreeding or the occasional mega drought.
"It's one of the most ridiculous fish habitats in the world," said Christopher Martin of the University of North Carolina, Chapel Hill, the lead author of the new study which appears online in the Proceedings of the Royal Society B.
Indeed, at 10 feet wide and 70 feet long (3.5 by 22 meters) the steep-sided Devil's Hole is the smallest range of any vertebrate in the world.
That same small range means it would not take much to wipe the species out, which is why Devil's Hole is fenced off from the public and guarded by the National Park Service. But the latest gene sequencing technology is changing the story of these fish, according to Martin.
And while they are still a critically endangered animal, genes have revealed that they aren't exactly the lonely remnants of the ice age they were long thought to be.
"We estimate that Devils Hole was colonized by pupfish between 105 and 830 years ago," report Martin and his colleagues.
That's based on their genetic sequencing which mapped out more than 13,000 genes and compared them to nearby pupfish species to determine how far the species had diverged from each other.
To estimate the time the species had been separated, they calibrated the rate at which the genes naturally change – the mutation rate – by comparing it to another, similar, pupfish species with a better-known mutation rate.
To the eye, the Devil's Hole pupfish is distinct from its neighbors. It's known for its missing pelvic fins, bigger eyes, and other characteristics that fit it to its unusual habitat. But the genetics indicate that not only is the fish relatively new to Devil's Hole, but that some of its genetic material has flowed back into the related pupfish of other watering holes.
But how did this impish little fish manage it? Perhaps, Martin offered, a rare duck visited Devil's Hole and inadvertently carried a few sticky pupfish eggs in, and decades or centuries later another carried some away. Or maybe it was humans – Native Americans, in particular – to whom the fish were a precious food source.
It's unlikely we'll ever know. But however they got there, it's now clear the pupfish adapted quickly to their new environment.
"Evolution can happen in decades to a few hundred years," said Craig Stockwell of North Dakota State University. "So it is possible that pupfish evolved shortly after colonizing Devils Hole."
Stockwell and his colleagues own research, published in 2015, concluded that there was a 2 percent probability of Devil's Hole pupfish surviving for 10,000 years and a 95 percent probability of them persisting for 133 years. The genetic sequencing would seem to agree.
There is another good reason to believe that fish could have changed rapidly after colonizing Devil's Hole, said Stockwell. Previous research had subjected another local species of pupfish to conditions similar to Devils Hole and found that the fish very rapidly took on traits that were similar to the Devils Hole pupfish.
"This suggests plasticity," said Stockwell.
As to how they got there, he said it's not so important scientifically, although it does add a certain mystique to what is already a devilishly interesting species.
The extremely rare Devil's Hole pupfish has an extremely limited habitat.
Lonesome George - the Last Pinta Island Tortoise
June 25, 2012 -
Lonesome George, the last Pinta Island giant tortoise and celebrated symbol of conservation efforts has died. George passed away in the Galapagos Islands with no known offspring after several attempts at breeding George with other similar tortoise species, according to AFP. Lonesome George's longtime caretaker, Fausto Llerena, found the giant tortoise's remains stretched out in the "direction of his watering hole" on Santa Cruz Island, according to AFP. Estimated to be more than 100 years old, the creature's cause of death remains unclear and a necropsy is planned. Lonesome George was discovered on Pinta Island in 1972 at a time when giant tortoises of his type, Geochelone nigra abingdoni, were already believed to be extinct, according to AFP. The following is a look at other at risk animals in the world.
NEWS: Extinct' Giant Tortoise Found on Remote Island
Animals at Risk Since the Endangered Species Act's passage 33 years ago, 1,800 species have been listed as endangered and nine have become extinct. ARKive, a collection of the world's best wildlife films and photographs, gathered together a list of the most at risk animals. The Tiger has undergone large population declines across Cambodia and the rest of Asia, according to ARKive.
Blue Whale (Endangered) Once hunted nearly to extinction, the blue whale is the largest animal to have ever lived, growing to around 27 meters (88.5 feet) long and weighing up to an astounding 120 tons. It also produces the loudest call of any animal on Earth. Although hunting of the blue whale was banned in 1966, the recovery of this magnificent marine mammal has been exceptionally slow.
Giant Panda (Endangered) The giant panda is universally admired for its appealing markings and seemingly gentle demeanor. A charismatic conservation icon, the giant panda is threatened by habitat loss, with large areas of China’s natural forest being cleared for agriculture, timber and firewood to meet the needs of the large and growing human population.
Tiger (Endangered) The tiger is one of the most emblematic symbols of conservation today, and its distinctively patterned coat and fearsome reputation make this species instantly recognizable. However, the tiger is facing the grave threat of extinction due to illegal poaching and habitat loss.
Sumatran Orangutan (Critically endangered) The name of the Sumatran orangutan means "person of the forest." The biggest threat to the Sumatran orangutan is the loss of its forest habitat, with around 80 percent of the forest on Sumatra vanishing in recent years due to illegal logging, gold mining and conversion to permanent agriculture, in particular, palm oil plantations.
Black Rhinoceros (Critically endangered) Contrary to its name, the black rhinoceros is actually grey in color. It was hunted almost to the brink of extinction for its impressive horn, which can grow up to 60 cm (23.6 inches), largely due to the demand for horn in Chinese traditional medicine and for traditional dagger handles in Yemen.
Philippine Eagle (Critically endangered) The striking Philippine eagle is the world's largest eagle and also one of the world’s most threatened raptors. The destruction of its habitat is the main cause of its dramatic decline, with vast tracts of tropical forests in the Philippines having been cleared for commercial development and for shifting cultivation.
Kakapo (Critically endangered) As the world’s only flightless parrot, the kakapo is a truly unique bird which is threatened by introduced species in its native home of New Zealand. Conservationists have taken the drastic measure of removing all surviving kakapo to predator-free islands, so far averting the extinction of this remarkable bird.
Hawksbill Turtle (Critically endangered) The hawksbill turtle possesses a beautiful marbled shell, which has been exploited for thousands of years as the sole source of commercial tortoiseshell. Illegal demand for its shell, and for its eggs, meat and even stuffed juveniles as exotic gifts, have led to the dramatic decline of this species over the last century. A further threat to the hawksbill turtle is global climate change.
Lemur Leaf Frog (Critically endangered) The lemur leaf frog is specially adapted for a life in the trees with adhesive pads on its toes. Eggs are laid on leaf surfaces and when hatched the larvae are washed off or fall into water below. This nocturnal tree frog was once considered to be a reasonably common species in Costa Rica, but it is threatened by the loss of its forest habitat and most populations in Costa Rica have recently disappeared.
Scalloped Hammerhead (Endangered) Forming impressively large schools, female scalloped hammerheads gather in the Gulf of California during the day, around underwater mountains known as seamounts, where they perform a wide range of behaviors yet to be understood. The scalloped hammerhead is under threat due to fishing pressures and in particular is a victim of shark finning. ANIMAL PLANET: Endangered Species Guide