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T-rex maybe not so mighty after all

Dan Jones and Charlotte Edwards, September 3, 2020 6:45PM The Sun

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T-Rex as seen in the Jurassic Park films. Picture: 2018 Universal City Studios Productions LLLP and Amblin Entertainment Inc media_cameraT-Rex as seen in the Jurassic Park films. Picture: 2018 Universal City Studios Productions LLLP and Amblin Entertainment Inc


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The king of the dinosaurs may not have been so mighty after all.

An international team of scientists — led by a palaeontologist* at the University of New England in New South Wales — have re-examined 100 years of dinosaur research.

They now believe the average T-rex may have weighed in at less than half of some previous estimates. The fearsome predator likely weighed on average seven tonnes, with individuals weighing between three and 18 tonnes.

The trouble with estimating dinosaur weights is that the only bits left are the bones. That’s good for working out the length and height of the extinct animals but not necessarily the mass*.

But by combining the most effective ways of measuring mass and body size in papers from 1905 onwards, palaeontologists have pieced together what they feel is the most accurate picture of the most famous dinosaur.

This involves two methods.

The first is to take the bones and use modern animals with similar features to scale up their weight – for instance, measuring the circumference* of an arm or a leg of a living creature and then multiplying it by the size of the T-rex equivalent bone.

This provides an accurate idea of the body mass but not what the animal may have looked like.

Dinosaur weights are just estimates based on their bones and what their flesh could have weighed Credit: GETTY IMAGES - GETTY media_cameraDinosaur weights are just estimates based on their bones and what their flesh could have weighed. Picture: Getty Images

The second method is to use computer remodelling programs based on the skeletons. This is believed to be a more accurate way to show what the dinosaur looked like, but not all that useful on its own to predict body mass.

The palaeontologists told the journal Biological Reviews that for this study, they combined the two methods.

Study leader Dr Nicolas Campione of the University of New England, said: “Body size, in particular body mass, determines almost all aspects of an animal’s life, including their diet, reproduction, and locomotion*.

“If we know that we have a good estimate of a dinosaur’s body mass, then we have a firm foundation from which to study and understand their life retrospectively*.

“It is only through the combined use of these methods and through understanding their limits and uncertainties that we can begin to reveal the lives of these, and other, long-extinct animals.”

Co-author, Dr David Evans of the Royal Ontario Museum in Canada added: “There will always be uncertainty around our understanding of long-extinct animals, and their weight is always going to be a source of it.

“Our new study suggests we are getting better at weighing dinosaurs, and it paves the way for more realistic dinosaur body mass estimation in the future.”

This story was first published on The Sun and is republished with permission.

Previous estimates have said the T-rex could have weighed up to 18 tonnes Credit: GETTY - CONTRIBUTOR media_cameraPrevious estimates have said the T-rex could have weighed up to 18 tonnes. Picture: Getty

Ferocious predator Tyrannosaurus rex was about 12m long (the length of a big bus) and about 4.6 to 6m tall.

It had strong thighs and a massive tail and it most likely used its 1.5m-long skull to bore into its prey.

It could probably eat about 230kg of meat in one bite.

Like crocodiles, T-rex laid eggs, but was more closely related to birds than to modern reptiles.

T-rex lived in forests in river valleys in North America until the species became extinct 65 million years ago.


  • palaeontologist: fossil scientist
  • mass: the amount of matter in an object; what we think of as weight
  • circumference: distance around the outside
  • locomotion: movement, or the ability to move
  • retrospectively: looking back and taking the past into account


World’s biggest T-rex unearthed

River ‘monster’ to topple T-rex as top dinosaur

Time capsule of the day the dinosaurs died

Giant meat-eating dinosaur roamed Australia


  1. What are the two ways of predicting what a dinosaur was like?
  2. What can the experts learn by knowing more about how much something weighed?
  3. How long was T-rex?
  4. How much could T-rex eat in one bite?
  5. Where did T-rex live?


1. Create a step-by-step guide
Design a step-by-step guide to the two different ways that scientists can work out the real size of dinosaurs. Rule: you can only use drawings or pictures.

Time: allow 30 minutes to complete this activity
Curriculum Links: English, Visual Communication Design, Science

2. Extension
If the only things we have left of the dinosaurs are bones, how do you think scientists work out what they looked like, other than their size? List as many ways that you can think of for things such as their skin, their colour, their shape and any other features.

Time: allow at least 20 minutes to complete this activity
Curriculum Links: English, Science, Critical and Creative Thinking

Down-Level It
When you up-level a sentence, you do things to it to improve it: make it more interesting, or more complex.

But sometimes, when we read something it can be too complex and we don’t understand it very well. You ask someone to explain it to you, they do (in a simpler way) and you think, well why didn’t they just say that?

Go through the article and find a sentence or two that is complex, or hard to read.

Ask an adult what it means, or try and look some of the words up in the glossary.

Once you know what it means, see if you can rewrite it in a simpler way- down-level it.

Make sure you don’t change the meaning of the sentence in any way though.

HAVE YOUR SAY: What extinct animal would you study?
No one-word answers. Use full sentences to explain your thinking. No comments will be published until approved by editors.

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