The age of the dinosaurs ended 66 million years ago. The theory of how they died is that a giant asteroid crashed into what is now southeastern Mexico.
Fires broke out across the planet and destroyed pretty much everything in its wake.
A new study published in the Journal of Evolutionary Biology says that the dinosaurs weren't the only animals that were wiped out.
They say, 93 percent of all mammals died as well. Additionally most mollusk species were impacted as did insects and terrestrial plants.
However, some mammals were able to survive and multiply because they were much smaller and could eat dying plants and insects.
Researchers say, dinosaurs weren't able to survive because they were much larger animals and required much more food.
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Dinosaur bones and illustrations
Dinosaur bones and illustrations
Fossil of a short-tailed pterosaur, a flying reptile, Pterodactylus kochi, Upper Jurassic Solnhofen limestone, Eichstaett, Germany, Photographed under controlled conditions (Specimen courtesy of Raimund Albersdoerfer, Germany), (Photo by Wild Horizons/UIG via Getty Images)
Fossil of a short-tailed pterosaur, a flying reptile, Pterodactylus kochi, Upper Jurassic Solnhofen limestone, Solnhofen, Bavaria, Germany, Photographed under controlled conditions (Specimen courtesy of Raimund Albersdoerfer, Germany), (Photo by Wild Horizons/UIG via Getty Images)
CANADA - OCTOBER 30: The spiked skull of a Styracosaurus, Toronto, Canada (Photo by Ira Block/National Geographic/Getty Images)
UNITED STATES - SEPTEMBER 09: A Hyolith from the Cambrian has an armored shell body, Museum of Natural History, Washington, District of Columbia (Photo by O. Louis Mazzatenta/National Geographic/Getty Images)
CANADA - MAY 30: The skull and crest of a Parasaurolophus, Toronto, Canada (Photo by Ira Block/National Geographic/Getty Images)
UNSPECIFIED - MARCH 23: Struthiomimus dinosaur hunting a dragonfly (Struthiomimus altus) (Photo by De Agostini Picture Library/De Agostini/Getty Images)
UNSPECIFIED - MARCH 23: Side profile of an aellosaurus walking (Photo by De Agostini Picture Library/De Agostini/Getty Images)
06/09/98 - Location- Smithsonian Natural History Museum caption- Nathan Myhrvold has some interesting theories on the evolution, disappearance of dinosaurs. His models have been created on computer. His day job is Chief Technical Officer of Microsoft. Rear is the Diplodocus that has the long tail with the fused sections in all the tails, leading Myhrvold to the belief that the dinosaur cracked its tail like a whip, the end section moving near the speed of sound. - Photo By Craig Herndon TWP (Photo by Craig Herndon/The Washington Post/Getty Images)
Dr Adam Yates, from the Bernard Price Institute for Paleontological Research, looks at the 'Aardonyx Celestae', a newly discovered fossil skeleton in Johannesburg on November 11, 2009. South African palaeontologists announced the discovery of a new species of 'transition' dinosaur that straddles the divide between the four-legged giant plant-eating sauropods and their bipedal carnivorous predecessors. The dinosaur roamed the area between 183 million and 200 million years ago, measured between 7 and 9 metres long. The specimen was a juvenile, which was aged between 7 and 10 years. The Aardonyx Celestae, as the new dinosaur has been named, was discovered on a farm in central Free State province in the Karoo Basin, an area rich in fossils. AFP PHOTO / ALEXANDER JOE (Photo credit should read ALEXANDER JOE/AFP/Getty Images)
UNDATED - In this handout provided by the Carnegie Museum of Natural History, an artist's redering depicts a previously unknown bird-like dinosaur that was formally introduced to the scientific community by scientists with the Smithsonians National Museum of Natural History, the Carnegie Museum of Natural History and the University of Utah March 19, 2014. Dubbed Anzu wyliei, referring both to a mythological feathered demon and the name of a Carnegie museum trustee's grandson, the seven-foot-tall creature weighed about 500 pounds when it roamed western North America 66 to 68 million years ago. (Illustration by Mark Klingler/Carnegie Museum of Natural History via Getty Images)
UNSPECIFIED - CIRCA 2003: Reconstruction of the flora and fauna of a marshy environment from the Jurassic Period, drawing. (Photo by DeAgostini/Getty Images)