If you drop an egg, from what height would you say it breaks?

One of the most common routes to get from the metropolitan area to La Seu d’Urgell and Andorra (which avoids the hefty toll of the Cadí tunnel) goes through Coll de Nargó. Almost everyone passes by without stopping. I have stopped there on occasion, to visit the Raiers Museum, the Romanesque church of Sant Climent... Today I stopped to discover another element of heritage, which invites a journey far back in time: Dinosfera. The name already attracts me. Soon, other things will attract me more.

Dinosfera is a center about dinosaurs and other ancient species that lived in this territory about 70 million years ago, when the Pyrenees were still forming. There were alluvial plains, with wetlands and watercourses. And the climate was much warmer than today: about 22 degrees on average annually (now it's 14 degrees). Yes, yes, it was much hotter!

Dinosfera is a very didactic space, for all audiences –children are the most demanding: there are those who know everything about these beasts!– It houses an important collection of fossils. One of the few fake pieces is located at the entrance. It is a magnificent reproduction of a sea turtle that lived in these lands, when they were still covered by the sea, about 83 million years ago. It has been possible to reproduce it thanks to the discovery of its pelvis and part of its shell (all fossilized, of course), which are on display.

"We made the turtle in here, at the museum – it has a very high ceiling – because otherwise it wouldn’t have fit through the door," Irina Fernández Duran, restorer and guide at Dinosfera, tells me. It is suspended: hanging it was quite a challenge because, although it is made of fairly light materials, it weighs about 250 kilos.

One of the panels that catches my eye the most at Dinosfera is the one that says a hen's egg breaks from 5 centimeters; a turtle's egg, from 10 centimeters; and an ostrich's egg, from 20 centimeters. This information is compared to that of a dinosaur egg, which has been calculated to break (used to break) from 40 centimeters. "The fact that it breaks from a small height tells us that the females probably had to stoop to lay their eggs," says Irina. And she adds: "But in reality, they couldn't stoop much. Therefore, there must have been something that made the fall of the eggs less abrupt, some system for laying them without breaking them. Perhaps they had an anatomical structure in their cloaca or they laid several eggs together surrounded by a mucus that cushioned the fall, like some current animals, or a combination of both." There are still many enigmas about dinosaurs yet to be discovered.

"In 2005, an impressive clutch of dinosaur eggs was discovered, attributed to titanosaurs (long-necked dinosaurs). These are eggs up to 20 centimeters in diameter," explains Àngel Galobart, paleontologist, coordinator of the Dinosaures del Pirineu project, and director of Dinosfera de Coll de Nargó.

At that time, paleontologists still did not suspect the scientific repercussions that this find would have. "Expansive cement was used to free the block containing the eggs," recalls Àngel, who is also a researcher at the Catalan Institute of Paleontology Miquel Crusafont. "And due to the enormous weight of the fossil (about two tons), a backhoe was necessary to be able to remove it from the site," he remembers.

"We are fortunate that many layers of terrain have been preserved in which the animals and plants from 70 to 66 million years ago have been recorded in the area where there were dinosaurs, which is not only Alt Urgell, where we are now, but also other areas of the Pyrenees, including Berguedà, Pallars Jussà and La Noguera. Thanks to this, we have an exceptional record that allows us to get closer to what this territory of present-day Catalonia was like at that time. For us, scientists, it is important to have found a great diversity of fossil remains. They are from dinosaur species completely different from those that lived in the territories that today correspond to the United States and China," he emphasizes. "Catalan dinosaurs," I say with a smile. "However, we recently discovered a small carnivorous dinosaur that is related to those that lived in China at that time," adds Àngel while I observe an eggshell, a complete egg, and another egg that preserves part of the sedimentary matrix that has surrounded it for millions of years. They are all from titanosaurs. "We have discovered a large part of the fauna that accompanied the dinosaurs: we have found turtles, crocodiles, flying reptiles, and, in addition, we have been able to reconstruct the landscape from the plant remains that have been preserved for so many millions of years.

The first discovery: in 1917It was during the construction of the water outlet channel of the Talarn dam, in 1917, that the first dinosaur fossil in Catalonia was found. However, it has not been until recent decades that the dinosaurs of the Pyrenees have been intensely investigated and disseminated. Lately, new analysis techniques have been developed that allow studying the interior of their fossils and knowing their internal structures and, in some cases, the growth rings of the bones.