Producer: Popular Science China
Production: 090811mario
Producer: Computer Network Information Center, Chinese Academy of Sciences
Dinosaurs, as top predators, dominated the world's terrestrial ecosystems for about 140 million years. Among them, sauropods are the largest land animals ever built, such as the famous Lepidosaurus, Confused Dragon and Argentinosaurus, which were tens of meters long and thick in skin when they reached adulthood, making a group of predators helpless. If so, who can eat dinosaurs? The answer may be, other dinosaurs.
However, thanks to some rare fossils, scientists have found that this is not the case, and there were many dragon slayers who went straight to the dragon's nest and ate the meat of the dragon in the dangerous Mesozoic Era. Adult dinosaurs are powerful, but when they are in the eggshell, or just out of the shell, they are very fragile and easy to be preyed upon.
<h1 class= "pgc-h-arrow-right" > the "ogre crocodile" that breaks into the dinosaur's lair, is it an ingredient on the buffet or a diner? </h1>
Fast forward to 2013, when scientists found a fossil site in the Pyrenees region of Europe, littered with Cretaceous dinosaur egg fossils. Based on the shape, thickness and ornamentation of the eggs, scientists have speculated that this was once the lair of a giantosaur. Titanosauria were a group of sauropods that replaced Lepidosaurus and Brachiosaurus as dominant dinosaur taxa during the Cretaceous period.
Subsequently, among the fragments of eggshells, scientists also accidentally found a crocodile-shaped animal fossil. However, before it could be excavated, it was stolen, and after many turns, the fossil was recovered, and finally in September 2020, the brave man who infiltrated the dragon's den was named Ogrerus furatus, which means "ogre crocodile".
△ (C) Black star refers to the fossil location of the ogre crocodile, surrounded by dinosaur eggs and eggshells (source reference [1])
The "Ogre Crocodile", belonging to the Sibe crocodile family, is related to the modern crocodile. With slender legs, curved teeth, excellent bite force, and stereo vision, they are a group of agile carnivorous crocodiles. The ogre crocodile is only about 1 meter long and weighs about 9 kilograms, making it one of the smallest and lightest members of the family, but it also lights up the skill of agile combat. Despite their name as "ogres", they don't have the opportunity to eat people, and their entire family was extinct 11 million years ago.
△ Ogre crocodile Ogresuchus furatus body size, scale 10 cm, white for preserved bones (source reference [1])
△ Ogre crocodile Ogresuchus furatus restoration. (Source reference[1])
Interestingly, the oval dinosaur eggs in the dragon's lair are 19-23 cm long axis, 15 cm short axis, and 2.1-2.5 mm thick (egg thickness is generally 0.3 mm), which is larger than the skull of the ogre crocodile, even if a strong dinosaur egg is stuffed into the mouth, it can not exert effective bite force on the dinosaur egg. At the same time, none of the 30 eggshells around it and the more than 1,000 eggshell fragments at fossil sites left holes and cracks related to predation, so the ogre crocodile should not have evolved the ability to prey on large dinosaur eggs.
△ Dinosaur egg fragment (black arrow) next to the ogre crocodile skeleton (gray element). (Source reference[1])
In this way, the emergence of such a little guy in the dragon's lair that can't bite eggs will inevitably make people feel like nature's "accidental masterpiece" - the flowing water carries the little guy's wreck here, or the dinosaur brings home his food.
However, buried evidence and a series of experiments have ruled out the effect of water transport. Moreover, the dragon-like dinosaurs were all plant-eating animals, and the tooth structure was only suitable for peeling off branches and leaves, and it was impossible to take the ogre crocodile back to the nest as food. So the "crocodile" brave the dragon's den is a real scene of the Cretaceous period.
Since egg nibbling is weak, it is certainly even more impossible to catch a large dinosaur, why should the "ogre crocodile" go to the dinosaur's lair?
Scientists have speculated that the ogre crocodile ventured into the dinosaur lair, probably to eat newly hatched dinosaur cubs. After all, why can't you get a dinosaur egg, or why can't you just break the shell of the cub?
Because dinosaurs gave birth to offspring by laying eggs, eggs are too large and easy to break, and thickening the eggshell will cause hypoxia in the embryo, so the size of the cubs will be limited. Even for the huge dragon dinosaurs, the newly hatched baby is a little bit small, probably about the same height as our calves. A 2016 study of juvenile dragon-like skeletons showed that individuals hatched with a weight of about 3 kilograms before rising to the ranks of dragons at an astonishing growth rate.
△ The gray silhouette is a newly hatched dragon (predatory dragon), and the far right femur represents the largest predatory dragon. (Source reference[2])
And the dragon newborns are fine skin and tender flesh, the armor has not yet developed, the sharp teeth of the ogre crocodile can easily pierce the dragon baby, it is simply a buffet, eat where you want.
But we can't intuitively feel this spectacular scene from the fossil, because there are no preserved cubs next to the fossil.
It doesn't matter, let's switch the scene to India in the same period, or to the scene of wandering around the dinosaur lair, the egg is still the egg of the dragon class, but the protagonist changes from "crocodile" to "giant snake", which also becomes more exciting.
<h1 class= "pgc-h-arrow-right" > break into dragon nests and eat baby dragons, and "giant snakes" also like it</h1>
In 2010, scientists discovered a precious fossil specimen from India that contained three eggs of a dragon, a dinosaur cub, and a snake, all of which were well preserved and barely deformed.
Named the Sanajeh indicus, this snake is about 3.5 meters long, its slender body is wrapped around baby dinosaurs and dinosaur eggs, and a broken eggshell is pressed under the body, what a spectacular prehistoric hunting scene!
△ The fossil and illustration of "Giant Snake Catching Dragon", the lower right corner is the baby dinosaur. (Source reference[3])
Every time you encounter this incredible fossil, it is always suspected that it was formed by nature's late transport, and fortunately, this fossil has also withstood the test of science.
The analysis showed that snakes and baby dinosaurs were likely to die from the rapid burial of mudslides caused by the storm, so that the two sides were frozen in eternity before they could react, and the hunting moment at that time survived to this day, becoming the first known evidence of snake-predatory dinosaur fossils.
△ The Indian ancient rift snake is attacking a model of a juvenile Titanosaurus. (Source Wikipedia)
<h1 class= "pgc-h-arrow-right" > is it eating eggs or newborn babies? </h1>
The Indian ancient slit snake is a relatively primitive snake that cannot open its mouth to 130 degrees like many modern snakes, so it faces the same problem as the ogre crocodile - the dinosaur egg is too big to eat. However, the Indian ancient slit snake may have broken dinosaur eggs to get their nutrients, as the current American glittering snake (Loxocemus bicolor) preys on the form of body wrapping around and crushing turtle eggs.
△ Loxocemus bicolor image source Wikipedia
In addition, the Indian ancient rift snake will not let go of the newborn dinosaur baby, because the newborns are fine skin and tender flesh, the size is not large, it is definitely the most suitable stage in the life of the dragon dinosaur to become a fresh buffet, and in a few years, there will be no chance to enjoy this blessing.
And later, scientists found two Ancient Indian Slit Snakes at the original excavation site, and both were related to giant dragon dinosaurs, which means that the snakes in this area during the Cretaceous period have developed a habit of wandering in the dinosaur nest and often staging the "giant snake dragon hunting" drama.
Thanks to these precious fossils, we can get a glimpse of the Cretaceous hunting scene across thousands of years, get a clue to the foraging behavior of prehistoric terrestrial carnivores, and reconstruct the eating habits of extinct creatures. But whether it is an ogre crocodile or an ancient Indian slit snake, the magnificence they show is only a moment in the past, and it is expected that more rare fossils of this kind will be found in the future, making the past no longer a handful.
bibliography:
[1] Sellés, A.G., Blanco, A., Vila, B. et al. A small Cretaceous crocodyliform in a dinosaur nesting ground and the origin of sebecids. Sci Rep 10, 15293 (2020). https://doi.org/10.1038/s41598-020-71975-y
[2] Curry Rogers, K., Whitney, M., Demic, M. & Bagley, B. Precocity in a tiny titanosaur from the Cretaceous of Madagascar. Science 352, 450–453 (2016).
[3] Wilson, J. A., Mohabey, D. M., Peters, S. E. & Head, J. J. Predation upon hatchling dinosaurs by a new snake from the Late Cretaceous of India. PLoS Biol. 8, e1000322 (2010).