Dinosaurs have fascinated adults and kids alike for centuries. Since the discovery of the first dinosaur fossil in the early 1800s, we’ve been captivated by these creatures who once dominated the planet. But have you ever wondered exactly how many dinosaurs lived here on earth? Here, we’re bringing you some figures from the experts.

How many dinosaur species are there?

Let’s first look at how many dinosaur species are known to us. It’s estimated that around 900 different valid species existed throughout the dinosaur age, which spanned 235 million - 65 million years ago. Valid means scientists have found enough bones to be relatively certain each individual species is different enough to have its own classification. 

How many dinosaurs were there?

Unfortunately this is an impossible question to answer because the fossil record is so limited. That means there simply aren’t enough fossils around for scientists to make an accurate assumption of how many dinosaurs lived at any one time. However, there have been some attempts to estimate how many individuals of a particular species roamed the earth.

Paeleontologists from the University of California, Berkeley set out to come up with a figure for how many tyrannosaurus rex were alive at any one time. Using the fossil record, density data and data from climate models, they calculated that there would have been around 20,000 adult T. rex living across North America at any given time. They then estimated that in total, 2.5 billion individuals of the species walked the earth during the 2.5 million years in which the T. rex existed.

Why is there so much guesswork?

The authors of the research estimate that only around one in 80 million T. rex are preserved as fossils. This shows the incredible rarity of information available to us on any one species, let alone all 900 or so species.

The population density of different types of dinosaur would have depended on a variety of factors including their lifespan, the size of their territory, the type and availability of food they ate, how many eggs they laid, and how often they reproduced. Coming up with a figure for how many there were is therefore a huge challenge, because most of these factors are unknowable.

Discover dinosaurs

We may never know exactly how many dinosaurs inhabited the earth, but fossils continue to give scientists information about these fascinating reptiles and their habits. If your family is dino-mad, don’t miss the dinosaur experience of the summer. Dinosaur World Live is one of the best dinosaur attractions in the UK, and is back on tour from 1 August 2024.

Aimed at families, it uses stunning puppetry to bring a selection of prehistoric beasts to life, including triceratops, giraffatitan, microraptor and, of course, T. rex. Search ‘dinosaur event near me’ to find out when Dinosaur World Live will be playing at your local theatre, and book your tickets today.