There’s plenty that archaeologists and paleontologists can learn from the bones and other artifacts left behind by ancient creatures and mankind’s own ancestors. Researchers can figure out what they looked like, where they lived, and who ate who, but painting a detailed picture of more advanced behavior is much more challenging. How ancient humans hunted, for example, is a huge topic of interest for many scientists, but evidence to support any theories is pretty rare.
A newly-discovered collection of fossilized footprints is giving researchers a rare glimpse into the past and helping them tell the story of how our ancestors once brought down a now-extinct creature that would have towered over them: the giant sloth.
The footprints, where were discovered at the White Sands National Monument, part of which is a US military testing ground. Today, the dry, barren location is a great place to test missiles without the risk of casualties, but 10,000 years ago it was the site of an epic battle between ancient humans and a massive ground sloth.
Giant sloths went extinct thousands of years ago, but at one time they were the target of human hunters. The reason for the species’ extinction is still debated, but some scientist blame overhunting as the cause. What these new footprints tell us for sure is that our ancestors seemed to have a pretty good idea of how to take them down, with circling footprints of multiple hunters surrounding one such sloth distracting it while others presumably attacked it with spears or other crude weapons.
“Geologically, the sloth and human trackways were made contemporaneously, and the sloth trackways show evidence of evasion and defensive behavior when associated with human tracks,” the researchers write in the study, published in Science Advances. “Behavioral inferences from these trackways indicate prey selection and suggest that humans were harassing, stalking, and/or hunting the now-extinct giant ground sloth in the terminal Pleistocene.”
Whether violent confrontations such as this were ultimately the cause of the giant sloth becoming extinct will likely never be conclusively proven, but the evidence that humans hunted these so-called “megafauna” on a large scale is mounting. Maybe that’s why modern animals are so darn small?
Scientists have proposed a number of possible culprits responsible for this mass extinction, including an asteroid impact, mercury poisoning, a collapse of the ozone layer, and acid rain. Heavy volcanic activity in Siberia was suspected to play a key role in the end-Permian event.
Recently, geologist Dr Benjamin Burger identified a rock layer in Utah that he believed might have formed during the Permian and subsequent Triassic period that could shed light on the cause of the Great Dying.
During the Permian, Earth’s continents were still combined as one Pangea, and modern day Utah was on the supercontinent’s west coast. Samples from the end-Permian have been collected from rock layers in Asia, near the volcanic eruptions, but Utah was on the other side of Pangaea. Burger’s samples could thus provide a unique perspective of what was happening on the other side of the world from the eruptions. Burger collected and analyzed samples from the rock layer, and documented the whole process in a fascinating video:
Earth turned into a toxic hellscape
Burger’s samples painted a grim picture of Earth’s environment at the end of the Permian period. A sharp drop in calcium carbonate levels indicated that the oceans had become acidic. A similar decline in organic content matched up with the immense loss of life in the oceans during this period. The presence of pyrite pointed to an anoxic ocean (without oxygen), meaning the oceans were effectively one massive dead zone.
Bacteria ate the oversupply of dead bodies, producing hydrogen sulfide gas, creating a toxic atmosphere. The hydrogen sulfide oxidized in the atmosphere to form sulfur dioxide, creating acid rain, which killed much of the plant life on Earth. Elevated barium levels in the samples had likely been carried up from the ocean depths by a massive release of methane.
The culprit: burning coal
Levels of various metals in the rock samples were critical in identifying the culprit of this mass extinction event. As in end-Permian samples collected from other locations around the world, Burger didn’t find the kinds of rare metals that are associated with asteroid impacts. There simply isn’t evidence that an asteroid struck at the right time to cause the Great Dying.
However, Burger did find high levels of mercury and lead in his samples, coinciding with the end of the Permian period. Mercury has also been identified in end-Permian samples from other sites. Lead and mercury aren’t associated with volcanic ash, but they are a byproduct of burning coal. Burger also identified a shift from heavier carbon-13 to lighter carbon-12; the latter results from burning fossil fuels.
The Permian was the end of the Carboniferous period, which means “coal-bearing.” Many large coal deposits were created in the Carboniferous, including in Asia. Previous research has shown that the Permian mass extinction event didn’t coincide with the start of the Siberian volcanic eruptions and lava flows, but rather 300,000 years later. That’s when the lava began to inject as sheets of magma underground, where Burger’s data suggests it ignited coal deposits.
The coal ignition triggered the series of events that led to Earth’s worst mass extinction. Its sulfur emissions created the acid rain that killed forests. Its carbon emissions acidified the oceans and warmed the planet, killing most marine life. The dead bodies fed bacteria that produced toxic hydrogen sulfide gas, which in turn killed off more species. The warming of the oceans produced a large methane release, which accelerated global warming faster yet. As Burger put it,
Things went from bad to worse, and you can now begin to understand how life nearly died out. Global warming, acid oceans, anoxia, not to mention a toxic atmosphere. We are lucky to be alive at all!
These are some of the similarities between the climate change that nearly wiped out life on Earth 252 million years ago and the climate change today. Both appear to have largely been caused by burning coal. A 2011 study found that over the past 500 years, species are now going extinct at least as fast as they did during the five previous mass extinction events.
Despite humans’ best efforts to destroy her, it seems Nature is not going down without a fight. And regardless of what humans may believe about themselves and their place at the pinnacle, Nature is ultimately much bigger, heavier and vastly more significant in the so-called ‘scheme of things.’
Could it all be part of a long-suffering and normally highly (even saintly) tolerant Mother Nature finally fighting back against her one fatal blunder–the fleshy, hairless, upright, arrogant apes armed with their weapons of mass extinction?
Homo sapiens may have won countless battles and the arms race hands-down, but Nature will ultimately win the day and eventually, the war, wiping the slate clean for another burst of evolutionary creativity that won’t include theconceited carnivorous primates or their puffed-up fantasies of self-importance.
It came to me while reading the nonfiction book What Evolution Is by the famed evolutionary biologist, Ernst Mahr, that the only way Mother Nature is ever going to get rid of the species plaguing her perfection is with a good old-fashioned mass extinction, because, sadly, humans aren’t going anywhere without taking just about every other species with them.
Humankind have backed Nature into a corner and at this point all she can do is turn and fight, like sow grizzly bear defending her beloved offspring.
Humans have gotten away with killing and eating, killing for sport and/or taking trophies of any and all of Natures’ finest treasures for so long now we’re starting to think we’re entitled to simply help ourselves to the spoils of our war on the world.
Well; if humans don’t shape up and show some respect, things could really start get ugly on this planet soonfor everyone involved… and that’s not just talking weather-wise.
The famed British naturalist warns that our current rate of population growth is unsustainable and will ultimately have devastating consequences for the human race.
He recommends several ways to combat this problem, emphasizing a need to give women political control of their bodies and investing in sex education worldwide.
“A PLAGUE ON EARTH”
David Attenborough, renowned British naturalist and TV presenter, has some pretty scathing words for humanity: “We are a plague on Earth.”
Attenborough made that statement to the Radio Times back 2013, but it’s far from the only time he’s shared his controversial views on population growth. Attenborough has made it clear that he believes that at the rate humans are growing we will soon be unable to feed or house ourselves. It’s an uncomfortable truth, but one that needs to be faced, especially for anyone who agrees with Attenborough that humans have become a plague on this planet — a relentless force of destruction tearing its way through a world shared with other creatures.
“It’s coming home to roost over the next 50 years or so. It’s not just climate change; it’s sheer space, places to grow food for this enormous horde,” he said in that same interview. “Either we limit our population growth, or the natural world will do it for us, and the natural world is doing it for us right now.”
The rapid growth of our population is making it very difficult for the world to address several serious environmental challenges. What’s needed is a real discussion about the reality of overpopulation. Too many people, combined with insufficient methods of creating and distributing resources, ultimately leads to loss of life and resources.
“We can’t go on increasing at the rate human beings are increasing forever, because Earth is finite and you can’t put infinity into something that is finite,” Attenborough said in a story published by The Independent.
TOO LITTLE, TOO LATE?
Despite all his efforts to bring awareness to the subject of overpopulation, Attenborough sternly warns that simply acknowledging these eventualities is not enough — we must act. He believes that controlling our population is dependent on investing in sex education globally, giving women more political control over their bodies, and implementing other voluntary means of population control in developing countries.
“The only straw of comfort or of hope, and even that is pretty fragile, is that wherever women are given political control of their bodies, where they have the vote, education, appropriate medical facilities and they can read and have rights and so on, the birth rate falls, there’s no exceptions to that,” Attenborough says.
Putting more emphasis on women’s reproductive rights and empowerment, as well as providing universal access to birth control and education, will ultimately give people an opportunity to make informed family planning choices. Our only hope of living on this planet for a long time into the future is making sure we start planning for it now.
Humpback whales have been dying in extraordinary numbers along the Eastern Seaboard since the beginning of last year. Marine biologists have a term for it — an “unusual mortality event” — but they have no firm idea why it is happening.
Forty-one whales have died in the past 15 months along the Atlantic coast from North Carolina to Maine. In a news conference on Thursday, officials from the National Oceanic and Atmospheric Administration Fisheries said that they had not identified the underlying reason for the mass death, but that 10 of the whales are known to have been killed by collisions with ships.
The agency is starting a broad inquiry into the deaths.
These whales “have evidence of blunt force trauma, or large propeller cuts,” said Deborah Fauquier, a veterinary medical officer at the agency’s Office of Protected Resources. These collisions with ships were “acute events,” Dr. Fauquier said, and were being treated as the “proximate cause of death.”
Dr. Fauquier said that the number of whale strandings was “alarming,” and that she hoped the investigation might give a sense of what kind of threat this presents to this population of humpback whales and those around the world.
COn average, eight humpback whales are stranded each year from Maine to Virginia, and fewer than two are hit by ships, according to data from NOAA.
Whale or other marine mammal die-offs are often poorly understood by scientists, and this case is no exception. Officials from NOAA Fisheries could not explain why the animals were coming into greater contact with vessels, or if there were any human-caused or climate-related disturbances that had changed their behavior.
Gregory Silber, marine resources manager in the agency’s Office of Protected Resources, said that there had not been any increase in ship traffic in the region, and that the whales might be following their prey — they mostly eat krill and small fish — to areas where there could be more shipping.
Ten whales other than those killed by ships have been examined, but officials have not yet determined the cause of death. There is no indication that they were killed by disease.
Humpback whales — which can be as long as 60 feet, weigh as much as 40 tons and can live for 50 years — are found in all of the world’s oceans. There are 14 distinct population segments — groups that follow certain migration and breeding patterns — of humpback whales, some of which are classified as endangered or threatened. The population along the Atlantic coast, which winters in the Caribbean and summers in the North Atlantic or Arctic regions, is not now considered threatened under the Endangered Species Act.
Around the world, there are an estimated 30,000 to 40,000 humpback whales, about a third of its original population. The Atlantic population is around 10,000.
Scientists have suggested that some whale deaths could be a result of marine noise, often a result of military activity, offshore drilling or exploration, which can disorient the animals and send them in the wrong direction, possibly toward beaches where they get stuck instead of into the deeper ocean. Mr. Silber, the NOAA manager, said he was not aware of a connection between ocean noise and these strandings.
A recent study has shown that dolphins, when escaping predators or the source of marine noise, might shoot up from a dive more quickly than they otherwise would, switching from slow, deliberate strokes to faster, longer ones, which can cause them to use double the energy they normally do, and exhaust them.
Among humpback whales, there was an unusual mortality event in 2006, following others in 2005, which involved other large whales, and 2003, which was primarily humpback whales. In each investigation, the cause was undetermined, officials said.
Bringing back extinct species could lead to biodiversity loss rather than gain, according to work featuring University of Queensland researchers.
UQ scientist Professor Hugh Possingham said the research suggested further stretching already-strained conservation budgets to cover the costs of de-extinction could endanger extant species (species still in existence).
“If the risk of failure and the costs associated with establishing viable populations could also be calculated, estimates of potential net losses or missed opportunities would probably be considerably higher,” Professor Possingham said.
“De-extinction could be useful for inspiring new science and could be beneficial for conservation if we ensure it doesn’t reduce existing conservation resources.
“However, in general it is best if we focus on the many species that need our help now.”
“Given the considerable potential for missed opportunity, and risks inherent in assuming a resurrected species would fulfil its role as an ecosystem engineer or flagship species, it is unlikely that de-extinction could be justified on grounds of biodiversity conservation.”
The study was led by Dr Joseph Bennett, formerly of the ARC Centre for Environmental Decisions at UQ and now of Carleton University, Canada.
It analysed the number of species governments in New Zealand and New South Wales could afford to conserve.
“We based cost estimates on recently extinct species and similar extant species,” Dr Bennett said.
The Lord Howe pigeon, eastern bettong, bush moa and Waitomo frog were among the extinct species included in calculations.
The researchers found reintroducing some recently extinct species to their old habitats might improve biodiversity locally, but government-funded conservation for 11 focal extinct species in New Zealand would sacrifice conservation for nearly three times as many (31) extant species.
External funding for conservation of the five focal extinct NSW species could instead be used to conserve more than eight times as many (42) extant species.
Although the technology for de-extinction is still some way off, the research found that careful thought would be required about what species to reintroduce, and where.
Professor Possingham is Chief Scientist with The Nature Conservancy, the world’s largest conservation organisation, and a scientist with UQ’s School of Biological Sciences, The Centre for Biodiversity and Conservation Science at UQ, the ARC Centre of Excellence for Environmental Decisions (CEED) and the Australian Government’s National Environmental Science Program Threatened Species Recovery Hub.