Here Are All The Craziest Dinosaur Facts That Have Been Discovered Since You Were In School

In an article published in the journal Proceedings of the National Academy of Sciences on July 6, 2020, researchers described a newly discovered ancestor to giant dinosaurs and flying pterosaurs dug up in Madagascar. The Kongonaphon kely is approximately 4 inches tall and 237 million years old.

The lead author on the study, Christian Kammerer, mused the Kongonaphon kely "would probably make a great pet." Its name means "tiny bug slayer," a reference to the idea that it would jump around on its hind legs catching bugs all day. 

Examining a section of the thigh bone allowed researchers to conclude the fossil is that of an adult. 

According to a study from UC Berkeley published in April 2021 in the journal Science, an estimated 2.5 billion T. rexes lived and died during their 2.5 million years on Earth, or about 20,000 at any given time. Paleontologists previously thought they couldn't calculate population numbers for animals that had been extinct for so long. But Charles Marshall, director of the University of California Museum of Paleontology and a UC Berkeley professor of integrative biology, said he realized an estimation might be possible using what is known about the relationship between population density and body mass among living species, known as Dalmuth's Law.

For their calculations, Marshall and his team characterized T. rex as an animal "with energy requirements halfway between those of a lion and a Komodo dragon, the largest lizard on Earth." Despite the strength of the relationship, there's a great deal of uncertainty, Marshall said, because "ecological differences result in large variations in population densities for animals with the same physiology and ecological niche."

From a series of data scientists already know about T. rexes, Marshall and his colleagues estimated the population at any given time was 20,000 individuals, and because the species lived about 127,000 generations, that would mean a total of 2.5 billion individual dinosaurs.

Due to uncertainties in the calculations, however, the actual number could range from 140 million to 42 billion.

Paleontologist Stephanie Drumheller-Horton, from the University of Tennessee-Knoxville, and her colleagues found hundreds of fossils at the Mygatt-Moore Quarry bonebed off the Colorado-Utah border. Of the 2,000 fossils found at the site, 28% showed punctures, scratches, and bite marks from other carnivorous dinosaurs, suggesting some species fed on their own kind. A survey of the bones published in the PLOS ONE academic journal suggests "the first evidence of cannibalism in Allosaurus" because of the "relative abundances of the carnivores, partnered with the size-estimates based on the striated bite marks, [and] the feeding trace assemblage." More likely these dinosaurs were scavengers, however, as opposed to actively hunting their own kind.  

Paleontologist Joseph Peterson, who was not involved in the study, told Smithsonian magazine the dinosaurs at the Mygatt-Moore Quarry site likely acted different because of weather conditions. During the dry season, meat like fish and crocodiles are rare, so carnivores might have picked at dinosaur carcasses searching for meat before the wet season buried the remaining bones and preserved them as fossils. 

Scientists have long assumed that the Tyrannosaurus rex was a lone predator. But researchers who analyzed fossils discovered at the Grand Staircase-Escalante National Monument in Utah suggested that T. rexes might have gone out hunting in groups. The scientists, who published their results in the journal PeerJ, wrote that "tyrannosaurids [the family of dinosaurs that includes T. rexes] are hypothesized to be gregarious, possibly parasocial carnivores engaging in cooperative hunting and extended parental care."

They came up with their theory based on studying the remains of at least four tyrannosaurids found near each other in the same Utah bonebed, most likely transported there by a flood. Although the scientists don't know for sure whether the dinosaurs perished "in a mass-mortality" scenario or "were transported from disparate localities," analysis of various physical and chemical elements suggests their deaths "were not widely separated in time."