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Study Says Dinosaurs Were Dying Off Long Before Massive Asteroid Hit Earth

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Your mental folder of dinosaur facts may need to be updated soon. Most people are taught at a young age that dinosaurs went extinct when a large asteroid struck Earth 66 million years ago, but according to new research, that may have been the last chapter of a 40-million-year-long story. As Discovery reports, a study published recently in the journal Proceedings of the National Academy of Sciences suggests that dinosaurs were already on the decline for tens of millions of years before the asteroid delivered the final blow.

The researchers from the University of Bristol and the University of Reading used a statistical approach and data from the fossil record to determine that as far back as 50 million years before the asteroid, species from the three major dinosaur groups (Ornithischia, Sauropodomorpha, and Theropoda) were going extinct faster than new ones were emerging. "We were not expecting this result," lead author Manabu Sakamoto said. "While the asteroid impact is still the prime candidate for the dinosaurs' final disappearance, it is clear that they were already past their prime in an evolutionary sense."

The researchers told Discovery that there were other global factors contributing to the demise of the dinos, including changes in climate, rising seas, and the evolution of early mammals, who may have "outcompeted dinosaurs for resources, eaten their eggs, spread diseases or caused other problems for the once mighty dinos." While their numbers may have been dropping, University of Edinburg paleontologist Steve Brusatte believes that dinosaurs would have held on for some time had the asteroid not struck. "The asteroid hit at a time when dinosaurs had already been around for a long time, and had already endured their really prolific periods of evolution," he said. "But the way I see it, the dinosaur extinction still came down to the asteroid. No asteroid, no extinction."

[h/t Discovery]

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John James Audubon, Wikimedia Commons // Public Domain
10 Tragic Stories of Extinct Animals
Drawing depicting the Great Auk, from the book 'Birds of America' by John James Audubon.
Drawing depicting the Great Auk, from the book 'Birds of America' by John James Audubon.
John James Audubon, Wikimedia Commons // Public Domain

The tale of the dodo is one of the most famous stories of extinction in all natural history. Native only to the tiny island of Mauritius in the Indian Ocean, the birds had never learned any reason to be fearful of humans, so when European explorers first began to visit the island in the 17th century, the dodos were apparently so unsuspecting they could be picked up by hand straight from the wild and killed. Although the dodo was never a particularly numerous species (the fact that it was flightless made it susceptible to floods and forest fires, which apparently kept its population naturally low), within less than a century of its discovery, interference by humans had led to its extinction. But it's by no means alone—the stories behind the disappearance of 10 other creatures are listed here.

1. ATLAS BEAR

A Roman mosaic of the extinct Atlas bear.
A Roman mosaic of the extinct Atlas bear.
The Picture Art Collection / Alamy Stock Photo

The Atlas bear was the only species of bear native to Africa, and once inhabited the area around the Atlas Mountains in the far northwest of the continent. The bear's lengthy demise can be traced all the way back to the time of the Roman Empire, when the animals were not only hunted for sport but captured, brought back to Rome, and made to battle gladiators and execute criminals in a gruesome spectacle known as damnatio ad bestias. Numbers continued to fall throughout the Middle Ages, when great swaths of forest in northern Africa were felled for timber, until finally the last surviving wild Atlas bear was shot and killed in the mid-1800s.

2. CAROLINA PARAKEET

A mounted Carolina parakeet
James St. John, Wikimedia Commons // CC BY 2.0

The Carolina parakeet was once the only species of parrot native to the United States, found across a vast expanse of the country from New York in the north to the Gulf of Mexico in the south and the Rocky Mountains in the west. Excessive hunting and trapping meant that the birds had already become rare by the 19th century, but large, isolated flocks were still being recorded until as recently as the early 1900s. Sadly the birds were known for their altruistic habit of flocking to attend to dead or dying members of the same flock—so if only a few birds were felled by hunters, many of the rest of the flock would remain nearby, making themselves easy targets. The last known specimen died in the Cincinnati Zoo in 1918, and the species was finally declared extinct in 1939.

3. DUSKY SEASIDE SPARROW

A Dusky Seaside Sparrow outside on a branch
U.S. Fish and Wildlife Service, Wikimedia Commons // Public Domain

In 1963, a decision was made by NASA to flood a vast area of marshland on Merritt Island in eastern Florida as a means of controlling the mosquito population around the Kennedy Space Center. Sadly, Merritt Island was also one of the last strongholds of the dusky seaside sparrow, a small dark-colored songbird, and when the land was flooded, so too was the sparrows’ main breeding ground. Drainage of the marshes around the St. Johns River for a highway project also contributed to habitat loss. The birds' population collapsed, and in the years that followed, the species struggled to regain its numbers. By 1979, only five birds—all males—remained in the wild, and the sparrow was finally declared extinct in 1990.

4. GRAVENCHE

A drawing of a gravenche, an extinct freshwater fish
Wikimedia Commons // Public Domain

The gravenche was a species of freshwater fish native only to Lake Geneva, one of the Alpine lakes that straddle the border between France and Switzerland. The fish were apparently once so common in the lake that it alone accounted for two-thirds of all of the fish caught in Lake Geneva. Due to overfishing, the population of gravenche (Coregonus hiemalis) began to decrease rapidly in the early 20th century; the last known sighting was in 1950, and the species is now considered extinct.

5. GREAT AUK

Study of a great auk, circa 1910.
Hulton Archive, Getty Images

The penguin-like great auk was a large, flightless seabird once native to the entire North Atlantic Ocean, from Greenland and eastern Canada to the British Isles and the westernmost coasts of Europe. The birds were highly prized for their light and fluffy down, which was used as a stuffing for pillows and mattresses. And like the dodo, the fact that the birds were flightless made hunting and capturing them easy. The European population was almost entirely eradicated by the late 1600s, leading to one of the earliest environmental protection laws in history, passed by the British Parliament in 1770s, that prohibited killing the auks in Great Britain. Sadly, it was too late. As the birds became scarcer, demand for their feathers, meat and pelts increased, and the last two breeding birds were unceremoniously strangled to death on their nest by a pair of Icelandic hunters in 1844, while a third man stamped on the single egg that the female had been incubating.

6. HEATH HEN

Three Heath Hens
Game Birds, Wild-Fowl and Shore Birds of Massachusetts and Adjacent States, Massachusetts State Board Agriculture, Wikimedia Commons // Public Domain

Like the great auk, the North American heath hen was also the subject of an early protective bill, introduced to New York State legislature in 1791, but it too failed to save the species from extinction. Heath hens were once native to much of the northeast United States, and were so plentiful that their meat eventually gained a reputation for being "poor man's food." Nonetheless they continued to be hunted in such vast numbers that by the mid-1800s there were no hens at all left on the entire American mainland. The bird's final stronghold was Martha's Vineyard, Massachusetts, but illegal poaching, diseases carried by domestic poultry, and predation from feral cats caused numbers on the island to fall to less than 100 by the mid-1890s. A hunting ban and a specialized Heath Hen Reserve were introduced in 1908, and in response the population swelled to over 2000 in the years that followed. But a fire during the 1916 breeding season undid all of the reserve's hard work, and by 1927 there were only 12 birds—including just two females—left alive. The last lone male, nicknamed "Booming Ben" by the locals, died in 1932.

7. JAPANESE SEA LION

The 8-foot-long Japanese sea lion—an even larger cousin of the Californian sea lion—was once native to the Sea of Japan and bred in vast numbers along the beaches of the Japanese islands and the Korean mainland. Sadly, the animals were hunted in enormous numbers, but not for the reason you might think: Their meat was poor quality and bad-tasting, so they weren't hunted for food, but rather for their skins (which were used to make leather), their bones (which were used in traditional medicines), their fat (which was rendered to make oil for oil lamps), and even their whiskers (which were used to make brushes and pipe cleaners). As recently as the early 1900s, more than 3000 sea lions were being killed every year in Japan, until the population collapsed to less than 50 individuals in 1915. Numbers remained low until the 1940s, when the maritime battles of the Second World War destroyed the last remaining colonies and much of their natural habitat. The last recorded (but unconfirmed) sighting was in 1974.

8. PASSENGER PIGEON

A stuffed passenger pigeon up for auction.
Rob Stothard, Getty Images

Until as recently as the early 1800s, the passenger pigeon was still considered the most numerous bird in all of North America. Individual flocks could contain in excess of a billion individual birds, and would take more than an hour to fly overhead. But as a hugely plentiful source of cheap meat, the birds were hunted in unprecedented numbers: At one nesting site in Michigan in 1878, as many as 50,000 birds were killed every day for nearly five months, and the last surviving flock of 250,000 birds was killed in its entirety by one group of hunters in a single day in 1896. The final individual bird—a female named Martha, who was being held in captivity at the Cincinnati Zoo—died in 1914.

9. STEPHENS ISLAND WREN

Wikimedia Commons // Public Domain

Stephens Island is a tiny half-mile islet lying in the seas between the two main islands of New Zealand. After a lighthouse was built there in 1892, the local lighthouse keeper's cat, Tibbles, caught a bird that the keeper didn't recognize. He sent the specimen to a renowned New Zealand ornithologist named Walter Buller, and the bird was soon declared a new species—the Stephens Island wren—and identified as one of only a handful of flightless perching birds known to science. Sadly, within just three years of its discovery, the species was extinct. According to popular history, Tibbles the cat was singlehandedly responsible for killing off the entire population of the wrens (in which case, Tibbles would be the only individual creature in history responsible for the extinction of an entire species), but in reality, by the late 1890s, Stephens Island was so overrun with feral cats that it is impossible to say that Tibbles alone was responsible: In February 1895, the lighthouse keeper wrote in a letter that "the cats have become wild and are making sad havoc among all the birds."

10. WARRAH

The warrah, or Falkland Island wolf or fox
Wikimedia Commons // Public Domain

The warrah, or Falkland Islands wolf, was a unique species of wolf that was once the only mammal species native to the Falkland Islands in the South Atlantic Ocean. It's thought that the species became trapped on the islands during the last Ice Age, when the Falklands were connected to the South American mainland by an ice bridge that left the animals isolated when it melted. After the Falkland Islands were first settled by humans in the 1760s, the wolves were seen as a threat to livestock and were quickly hunted into extinction. The warrah was already rare by the time Charles Darwin visited the Falklands in 1833, and he ominously predicted that, "within a very few years … this fox will be classed with the dodo as an animal which has perished from the face of the earth." Like the dodo, the warrah had never had to learn to be fearful of humans, and with no trees or forests on the island in which to hide, the wolves proved easy targets. The last individual was killed in 1876.

This story was first published in 2014.

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VaquitaCPR
11 Facts About the Vaquita, The World's Most Endangered Porpoise
VaquitaCPR
VaquitaCPR

The vaquita is the rarest marine mammal in the world, and critically endangered, according to the International Union for the Conservation of Nature (IUCN). Scientists estimate there are just 30 of the porpoises left in the world—and some recently said there may be as few as 12. Either number is likely too few for the vaquita to successfully reproduce and replenish its population. Here are 11 things to know before this species disappears forever.

1. SCIENTISTS FIRST IDENTIFIED THE VAQUITA IN 1958.

vaquita

Wikimedia Commons // Public Domain

In 1950, University of California scientist Kenneth Norris found a bleached skull on a beach north of Punta San Felipe in Baja California, and a year later, his colleagues found two more. When a colleague compared the skulls to those of another porpoise at the Museum of Vertebrate Zoology at Berkeley, California, they noticed differences striking enough to consider the finds a new species. Norris first described Phocoena sinus (gulf porpoise) in the Journal of Mammalogy in 1958.

2. ITS NAME MEANS "LITTLE COW" IN SPANISH.

The vaquita measures about 5 feet long (the females are slightly larger than the males) and weighs no more than 100 pounds. They're the smallest of all porpoises, with chunky bodies and rounded heads. Dark rings surround their eyes and mouths, which may account for their common name (vaquita means “little cow” in Spanish). Living in relatively shallow, cloudy water, they feed on a variety of fish, squid, and crustaceans.

3. SCIENTISTS CAN IDENTIFY INDIVIDUAL VAQUITAS BASED ON A SINGLE FEATURE.

Some vaquitas have individually distinctive nicks and notches on their dorsal fins, which makes it possible to identify specific individuals from high-quality photographs. Beginning in 2008, scientists created a catalog of these photos, adding new individuals and recording sightings of previously identified animals. Photo ID catalogs serve as a tool to help track an individual, revealing its life history, social organization, movements, and habitat use. Researchers use them with many marine animals that have distinctive markings. Individual manta rays, for example, can be identified by the spot patterns on their undersides.

4. THE VAQUITA IS FOUND IN ONLY ONE PLACE IN THE WORLD.

researchers try to spot the elusive vaquita in the Gulf of California
VaquitaCPR

Vaquitas live only in the northern Gulf of California, the body of water between Baja California and mainland Mexico. They're homebodies, staying within the northernmost part of the Gulf, and have the smallest range of any cetacean (the taxonomic order including whales, dolphins, and porpoises). Vaquitas reproduce only once every two years, while most porpoises have a calf every year. They're most closely related to porpoises in South America, but the species diverged from these relatives at least 2.5 million years ago.

5. UP TO 15 PERCENT OF VAQUITAS DIED IN FISHING NETS EVERY YEAR.

For decades, fishermen after shrimp and finfish such as corvina and sierra unintentionally entangled and drowned vaquitas in their gillnets; these long, curtain-like nets float in the water, snagging the gills of fish and shrimp that swim into them. A study showed that boats from a single fishing port in the upper Gulf accounted for the fatal bycatch of 39 to 84 vaquitas each year—an annual death sentence for 7 to 15 percent of the total population.

By the 1980s, the problem had become so bad that the vaquita was listed as endangered under the U.S. Endangered Species Act in 1985 and a year later as vulnerable on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species. Some good news came when UNESCO declared the upper Gulf of California a Biosphere Preserve in 1995, but it didn't do much good—just a year later, the IUCN changed the vaquita's status to critically endangered.

6. FISHING NETS MEANT TO BE VAQUITA-PROOF COULDN'T COMPETE WITH ILLEGAL FISHING …

In 2006, scientists and conservationists began developing gear that could catch fish and shrimp without harming vaquitas, including smaller nets dragged behind boats that the porpoises could avoid. Some fishermen in the Gulf agreed to test the gear. The initial results looked promising, and those efforts may well have eventually succeeded, but a bigger threat loomed: illegal fishing for totoaba, a large fish that had also been critically endangered for two decades. A single dried swim bladder of a totoaba can fetch as much as $50,000 in China, where they are given as gifts, eaten, or used in traditional medicine. People fishing illegally for totoaba continue to use gillnets, outweighing any benefit the safer, vaquita-proof nets might have had.

7. … SO THE FIRST OFFICIAL POPULATION ESTIMATE, IN 1997, WAS BAD NEWS.

Scientists have a hard time making precise estimates of the number of rare and cryptic (hard to find) species such as the vaquita. These porpoises prove particularly challenging, as they tend to avoid motorized boats, travel alone or in pairs, and are barely noticeable when they surface to take slow breaths. They're so shy that some locals say they've never seen one.

In 1997, scientists from the U.S. and Mexico spent days aboard a 170-foot ship motoring in a grid pattern over water up to 165 feet deep, trying to spot and count vaquitas. They estimated the total population was 567, which probably already reflected a significant decline due to intense fishing activity and less water emptying into the Gulf from the Colorado River, which was siphoned upstream by farms and towns. The IUCN ran models using fisheries data, the 1997 population number, and other counts, and estimated that, in the early 20th century, the vaquita population may have been 5000.

8. IN 2005, THE MEXICAN GOVERNMENT BANNED GILLNETS TO PROTECT VAQUITAS.

Directors of the World Wide Fund for Nature (WWF) in Mexico Maria Jose Villanueva (L), Jorge Richards (C) and Enrique Sanjurjo speak about the serious situation of the vaquita marina (Phocoena sinus) during a press conference in Mexico City on May 15, 201
Pedro Pardo, AFP/Getty Images

The alarming 1997 count spurred scientists to form the International Committee for the Recovery of the Vaquita (CIRVA in Spanish), operating with an environmental division of the Mexican government. Mexico established a Vaquita Refuge in 2005 and, after many years of urging by the members of CIRVA to permanently ban gillnets, recently prohibited all gillnet fishing in the porpoise's range—but just for two years. Mexico also provided compensation equivalent to millions of dollars to local people in the fishing industry left high and dry by the ban.

Conservation groups such as Greenpeace, the World Wildlife Fund, and Sea Shepherd Conservation Society patrol the Gulf for illegal fishing, but the totoaba trade continues. The black market money is just too good, says Andy Read, a marine biologist at Duke University and member of CIRVA. "From the perspective of the fishermen, what they could make legally fishing versus illegally fishing for totoaba, there is enormous incentive," Read tells Mental Floss. And, as a recent CIRVA report notes, "laws and enforcement are simply too weak to deter or prevent illegal fishing."

9. DESPITE THESE EFFORTS, THE VAQUITA POPULATION CONTINUED TO PLUMMET.

In 2008, CIRVA scientists conducted another ship-based visual survey, scanning the water for vaquitas with high-powered binoculars that could see as far as 3 miles. (Vaquitas tend to stay at least a half-mile away from boats.) They estimated the vaquita population at 245. In 2011, they tried another count, this time relying not on sightings of vaquitas, but a more accurate measure: passive acoustic monitoring devices in the water that detect sounds made by the animals. Vaquitas and other porpoises navigate by echolocation, producing distinctive clicks and whistles. "The devices look for a particular frequency," Read explains. "Nothing else makes sound in the same range, and vaquitas are acoustically very active."

For the next four years, they acoustically monitored Gulf waters—and were dismayed to see the vaquita population drop by 34 percent per year. Another CIRVA survey in 2015 combined visual and passive acoustic data collected simultaneously and made a dismal finding: Only 59 vaquita remained. The population had plummeted by 92 percent since 1997.

10. IN 2017, SCIENTISTS ATTEMPTED TO KEEP VAQUITAS IN A SEA PEN.

temporary sea pen for vaquitas in gulf of california
VaquitaCPR

In 2017, CIRVA scientists desperate to find a solution recommended a controversial plan: Capture vaquitas, keep them in net pens in the Gulf, and hope they would reproduce.

They had no idea whether it would work. No vaquita had ever been kept in captivity, no one knew how the animals would respond, and the effort would only pay off in the unlikely event that gillnet fishing in the Gulf completely stopped. Still, they formed an international team called VaquitaCPR to give it a try. The group subsequently built a high-tech "floating sea enclosure," which they anchored in the Gulf not too far from the beach where the first vaquita skulls were discovered.

In October 2017, VaquitaCPR scientists managed to capture two of the animals. The first, a young female, showed signs of stress—including increased heart rate and respiration rate—so they immediately released her. The second, a mature female, was transported in a stretcher placed inside a box partially filled with sea water to one of the pens and initially seemed to handle the experience well. Then she began swimming frantically and crashing into the sides of the net before finally going limp. The team released her, but she panicked, swimming at the net again. Veterinarians on the team jumped into the water, realized she wasn't breathing, and attempted to resuscitate her. Three hours later, they declared the animal dead, likely due to cardiac arrest.

After that, Read and many other scientists say they were heartbroken, but still felt that the risk of extinction outweighed those of capture. Others disagreed.

"Porpoises generally, like most cetaceans, do not fare well in captivity," Will McCallum of Greenpeace tells Mental Floss. "The population was already drastically depleted, and any capture or rounding up adds extra stress to the remaining animals. The likelihood of vaquita surviving, breeding and being released was slim."

Efforts continue to enforce the gillnet ban and remove gillnets in the reserve, but they may be too little, too late. "We should have been perfectly able to save the vaquita,” McCallum says. "We know where they are and what needed to happen to save them in the wild."

11. SCIENTISTS HAVE SAMPLED AND PRESERVED VAQUITA CELLS.

Some hope remains, though; cell samples taken by the VaquitaCPR team from the two captured vaquitas have been successfully cultured in the lab and frozen for use in future research. Scientists also plan to use the cells to sequence the vaquita genome.

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