Mother dinosaurs brought together to protect their eggs from predators, just like their relatives of birds, reveals an 80 million-year-old breeding ground in Mongolia.
Experts long believed that dinosaurs had complex, social breeding behavior, but it was difficult to demonstrate that adjacent fossil nests were being made at the same time.
At the so-called nesting site of Javkhlant, however, a deposit of sediments during a flood imposed a marker in the rock archive that connected 15 nests.
Researchers were also able to study the successful outcome of the nests, finding them similar to modern birds and crocodiles guarding their nests.
In contrast, those animals that leave their nest or leave unattended usually manage to breed less young.
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Mother dinosaurs brought together to protect their eggs from predators, just like their bird lovers do today, unveils an 80 million-year-old breeding ground (artist & # 39; s impression)
Paleontologist François Therrien of the Royal Tyrell Museum of Paleontology in Alberta, Canada, and colleagues discovered the dinosaur nesting site in the Gobi desert, southeast Mongolia.
The site has preserved the fossils of 15 dinosaur nests – with a total of more than 50 eggs each with a diameter of about 4-6 inches (10-15 centimeters) – that date from about 80 million years ago.
Based on the texture, size and shell thickness of the eggs, the researchers believe they are probably located by a theropod dinosaur – one of a large group that includes such famous members as Tyrannosaurus and velociraptors.
Experts have increasingly found evidence suggesting that dinosaurs cared for and protected their young – such as by hatching eggs.
However, the breeding ground of Javkhlant shows that nesting of groups – a behavior seen in modern birds and crocodiles that help animals deal with predators – had also developed in dinosaurs long before modern birds deviated from their ancestors.
& # 39; Dinosaurs are often portrayed as solitary creatures that only nested, buried their eggs, and then simply left, & # 39; said Dr. Therrien. Nature.
& # 39; But here we show that some dinosaurs were much nicer. They came together and set up a colony that they probably protected, & he added.
The challenge in studying nesting behavior was rather to prove that nests that were kept side by side in the rock were made simultaneously – instead of years after each other.
Experts long believed that dinosaurs had complex, social breeding behavior, but it was hard to prove that adjacent fossil nests were being made at the same time
At the so-called Javkhlant nesting site, however, a chance deposit of sediments during a flood laid a marker in the rock formation that connected 15 nests.
However, the researchers had a windfall at the newly discovered breeding ground.
The so-called Javkhlant formation of rocks in which the nesting site was found covers around 3,078 square foot (286 square meters) and is made up of vivid layers of orange and gray-colored sediments – but the most important aspect is a thin, bright red layer.
As this layer visibly connects the couplings – and even partially fills a portion of the eggs that are believed to have hatched – researchers can be sure that these nests were in use at the same time.
Researchers were also able to study the successful outcome of the nests, to find them similar to modern birds and crocodiles guarding their nests
The researchers think the characteristic layer probably formed when a nearby river flooded and covered the breeding ground with a thin layer of sediment.
& # 39; Because everything is relatively undisturbed, it was probably not a major flood, & # 39; Therrien said to nature.
& # 39; Sometimes you can find out a fascinating and detailed story about the ecology and behavior of these animals by simply looking at the rocks themselves, & # 39; he added.
By counting the number of fragmented eggs around the location, the researchers estimate that more than half of the eggs had at least one viable hatch.
These high success rates correspond to those of modern birds and crocodiles guarding their nests, as opposed to those who either leave their hatched offspring or check them irregularly.
& # 39; Geologically, I don't think we could have asked for a better site & # 39 ;, co-author of paper and Palestinian paleontologist Darla of the University of Calgary Zelenitsky told nature.
The full findings of the study were published in the journal Geology.
François Therrien of the Royal Tyrell Museum of Paleontology in Alberta, Canada, and colleagues discovered the dinosaur nesting site in the Gobi desert, southeast Mongolia
WHY DOES THE DINOSAUR EXTINCT GO?
Dinosaurs ruled and dominated the earth about 66 million years ago, before they suddenly died out.
The extinction of the Cretaceous tertiary extinction is the name given to this massive extinction.
For many years it was believed that the changing climate destroyed the food chain of the huge reptiles.
Paleontologists discovered a low iridium in the 1980s.
This is an element that is rare on Earth but is found in large quantities in space.
When this was dated, it exactly coincided with the disappearance of the dinosaurs from the fossil record.
A decade later, scientists discovered the huge Chicxulub crater at the tip of the Yucatán peninsula in Mexico, dating back to the period in question.
Scientific consensus now says that these two factors are interrelated and they were both probably caused by a huge asteroid that crashed to the earth.
With the projected size and impact speed, the collision would have caused a huge shock wave and probably triggered seismic activity.
The precipitation is said to have resulted in plumes of ash that probably covered the entire planet and made it impossible for dinosaurs to survive.
Other animals and plant species had a shorter time span between generations that allowed them to survive.
There are several other theories about the cause of the fall of the famous animals.
An early theory was that small mammals ate dinosaur eggs and another suggests that poisonous angiosperms (flowering plants) eliminate them.
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