Tyrannosaurus rex outnumbered 2.5 billon

According to a new study at the University of California more than 2.5 billion Tyrannosaurus rex roamed the earth more than million years ago.

Key findings of the study

  • The numbers of the dinosaurs were calculated based on body size and sexual maturity. These dinosaurs lived over 127,000 generations.
  • Though huge in number, their population density was small.
  • There were probably two dinosaurs in a region that was as big as a city.
  • The study helped the scientists to determine the preservation rate of Tyrannosaurus rex fossils.
  • So far, hundred fossils of T rex have been found on the earth.

How was the population calculated?

The scientists calculated the population of the dinosaurs based on the general biological rule that the bigger the animal, the less dense is their population. They then calculated the amount of energy needed by T rex to stay alive. They also used the fact that these dinosaurs lived for twenty eight years and reached maturity around fourteen to seventeen years.

Indian Fossil records of Dinosaurs

The oldest Indian Fossil record of dinosaurs belongs to the Triassic period. Triassic period is between 251.9 million years ago and 201.3 million years ago.


  • Dinosaurs first appeared during Triassic period.
  • They became the dominant terrestrial vertebrates after Triassic-Jurassic Extinction event.

Triassic-Jurassic Extinction event

The event that killed all the terrestrial ecological niches is called Triassic-Jurassic Extinction event. It killed more than 23% to 34% of marine species. After this event, the dinosaurs became the most dominant species.


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