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Confirmed: Some dinosaurs did nest in colonies
An unexpectedly revealing find in Mongolia solves a longstanding riddle.
- Normal geological evidence isn't precise enough to confirm paleontologists' suspicions.
- The new fossils find is covered by a fine veneer of red sand deposited in a single season.
- Scientists can infer whose eggs they were.
Paleontologists suspected that some dinosaurs nested in colonies, but it was impossible to know for sure. Yes, they'd often found what appeared to be groups of fossilized eggs. But did these egg "clutches" date from the same time, or had they gradually accumulated in a popular nesting area?
An unusual layer of sediment recently found in the Gobi desert appears to finally answer this question: At least one group of dinosaurs definitely nested and protected their clutches as a colony. A report of the find was published Jul 15 in Geology.
Why paleontologist have been wondering
Crocodiles lay eggs together in nests that they guard and protect as a colony. There are also a variety of modern birds that do this: seabirds such as auks and albatrosses, wetland birds like herons, and even some blackbirds and swallows. As descendants of dinosaurs, experts have wondered how far back this goes. Since the first dinosaur eggs were unearthed in France in 1859, paleontologists have been finding them in hundreds of locations around the world, and in 1978, the first evidence of a nesting colony was discovered in western Montana. Such clutches contain anywhere from 3 to 30 eggs.
Dating of such fossils is typically imprecise, however. A layer of rock covering a find may take millions of years to lay down, and can only suggest approximate ages of individual fossils. Though radiocarbon dating using Carbon-12 isotopes has a margin of error of just decades, that's still not quite close enough to establish that the eggs were actually contemporaneous.
The thin red line
The Gobi desert is the site of countless dinosaur fossils
Image source: Galyna Andrushko / Shutterstock
It took some extraordinary good luck to finally solve the riddle. In 2015, a group of paleontologist including some from Canada's Royal Tyrrell Museum and the University of Calgary came across a large deposit of dinosaur eggs in China's southeast Gobi Desert, in the Javkhlant formation. There were 15 nests and over 50 eggs about 80 million years old in a 286 square-meter formation.
What made the find so unusual, and ultimately dispositive, was the thin veneer of red rock, likely deposited in a single breeding season, that covered all of the eggs. It's believed to be sand deposited by flooding from a nearby river. "Because everything is relatively undisturbed, it likely wasn't a massive flood," says François Therrien. Adds Darla Zelenitsky, another co-author, "Geologically, I don't think we could've asked for a better site." Equally compelling, some 60 percent of the eggs had already hatched and had the red sand inside them.
This "was a demonstration that all of these clutches were actually a true dinosaur colony and that all those dinosaurs built their nests in the same area at the same time," asserts Therrien.
Whose eggs were they?
A mock-up, not real hatchlings.
Image source: Jaroslav Moravcik/Shutterstock
The find also offered up some insights into who these eggs belonged to. The texture and thickness of the eggs suggests their parents were non-avian theropods, a group that includes velociraptors. Not that these particular theropods were necessarily so fleet of foot.
"These animals were relatively big," Therrien tells CBC News, "They were around seven to nine meters in length, so way too big to fly. And they would have been covered with feathers, but very primitive types of feathers… hairy and light. They would not have had wings and would have been unable to fly." Such dinosaurs had, he adds, "a long neck, small head, but they have very, very large hands and very, very long claws on their four limbs," likely for defense.
The scientists were also able to infer something about the dinosaurs' parental behavior by comparing the rate of successful hatches to modern animals such as crocodiles and birds that guard their eggs. The survival rate strongly suggests that the colony protected their progeny throughout the incubation and hatching process, rather than abandoning them. Says Therrien, "If we compare that to modern animals, we see a very high hatching success like that around 60 percent among species where one or several parents guard in their colony. Basically, if the adults leave — abandoned the nest — we have a much lower hatching success because the eggs either get trampled or get predated upon."
"Sometimes you can extract a fascinating and detailed story about the ecology and behavior of these animals simply by looking at the rocks themselves," he notes.
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Construction of the $500 billion dollar tech city-state of the future is moving ahead.
- The futuristic megacity Neom is being built in Saudi Arabia.
- The city will be fully automated, leading in health, education and quality of life.
- It will feature an artificial moon, cloud seeding, robotic gladiators and flying taxis.
The Red Sea area where Neom will be built:
Saudi Arabia Plans Futuristic City, "Neom" (Full Promotional Video)<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="c646d528d230c1bf66c75422bc4ccf6f"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/N53DzL3_BHA?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span>
Many of the most popular apps are about self-improvement.
Emotions are the newest hot commodity, and we can't get enough.
Frequent shopping for single items adds to our carbon footprint.
- A new study shows e-commerce sites like Amazon leave larger greenhouse gas footprints than retail stores.
- Ordering online from retail stores has an even smaller footprint than going to the store yourself.
- Greening efforts by major e-commerce sites won't curb wasteful consumer habits. Consolidating online orders can make a difference.
A pile of recycled cardboard sits on the ground at Recology's Recycle Central on January 4, 2018 in San Francisco, California.
Photo by Justin Sullivan/Getty Images<p>A large part of the reason is speed. In a competitive market, pure players use the equation, <em>speed + convenience</em>, to drive adoption. This is especially relevant to the "last mile" GHG footprint: the distance between the distribution center and the consumer.</p><p>Interestingly, the smallest GHG footprint occurs when you order directly from a physical store—even smaller than going there yourself. Pure players, such as Amazon, are the greatest offenders. Variables like geographic location matter; the team looked at shopping in the UK, the US, China, and the Netherlands. </p><p>Sadegh Shahmohammadi, a PhD student at the Netherlands' Radboud University and corresponding author of the paper, <a href="https://www.cnn.com/2020/02/26/tech/greenhouse-gas-emissions-retail/index.html" target="_blank">says</a> the above "pattern holds true in countries where people mostly drive. It really depends on the country and consumer behavior there."</p><p>The researchers write that this year-and-a-half long study pushes back on previous research that claims online shopping to be better in terms of GHG footprints.</p><p style="margin-left: 20px;">"They have, however, compared the GHG emissions per shopping event and did not consider the link between the retail channels and the basket size, which leads to a different conclusion than that of the current study."</p><p>Online retail is where convenience trumps environment: people tend to order one item at a time when shopping on pure player sites, whereas they stock up on multiple items when visiting a store. Consumers will sometimes order a number of separate items over the course of a week rather than making one trip to purchase everything they need. </p><p>While greening efforts by online retailers are important, until a shift in consumer attitude changes, the current carbon footprint will be a hard obstacle to overcome. Amazon is trying to have it both ways—carbon-free and convenience addicted—and the math isn't adding up. If you need to order things, do it online, but try to consolidate your purchases as much as possible.</p><p>--</p><p><em>Stay in touch with Derek on <a href="http://www.twitter.com/derekberes" target="_blank">Twitter</a>, <a href="https://www.facebook.com/DerekBeresdotcom" target="_blank">Facebook</a> and <a href="https://derekberes.substack.com/" target="_blank">Substack</a>. His next book is</em> "<em>Hero's Dose: The Case For Psychedelics in Ritual and Therapy."</em></p>
Building a personal connection with students can counteract some negative side effects of remote learning.