Movies, lies and T-Rex

Although movies like Jurassic Park, The Lost World and King Kong may have us think otherwise, the T-Rex didn't live in Jurassic times. The Jurassic time period was from 206-144 million years, well before T-Rex terrified the plains of what we now know as North America (USA and Canada). T-Rex lived in the Cretaceous period, 75-65 million years ago.

T-Rex was one of the biggest and scariest meat-eaters. Only the Allosaurus and Gigantosaurus were larger and as scary. I really don't mind when it lived as long as it's not now.

The 14m (about 10 times your height) T-Rex had a huge 1.5 metre head as long as your body. It was filled with 60 blade like teeth, each up to 23 cms in length, about the distance from your elbow to your fingertips.

You'd think that the T-Rex would be easy to see. Using it's large tail to balance on 2 powerful hind-legs it stalked many other dinosaurs, especially the plant eating herbivores, for food. The woodlands of North America where the T-Rex lived had clearings in which it would chase and kill it's prey whereas the conifer, oak, maple and other trees provided perfect cover for the T-Rex to hide amongst.

With it's next meal in sight (and a ferocious roar) a T-Rex would break cover and chase it's prey at speeds up to 36-40 km per hour, taking steps or strides around 4 metres long. WOW! Our walking strides are much less than 1 metre.

But...could it really run at a speed of 40 kms per hour?

How fast T-Rex ?

No-one is or can be certain exactly how fast T-Rex was.

By measuring the distance between fossilised footprints (up to 4 metres) of T-Rex, knowing the size and length of its fossilised leg and foot bones, and by estimating how much muscle it had on its legs, scientists used to believe the T-Rex could run around 36-40 km/hr.

More recently though the T-Rex's speed has slowed! Some scientists have sugested it's speed to be only about 24 km/hr, others even slower at 14-15 km/hr. T-Rex had a long thigh bone, was very large and heavy, its front arms were tiny and more-or-less useless, and a very large part of its brain was used for smelling. These say that the T-Rex was probably a scavenger and not a predator or hunter. It could smell things up to 35 kms away and then walk or run slowly to a real predator's kill...

Would T-Rex win a Dino-race?

T-Rex would not win a race against other dinosaurs.

In a race against other 'quick' dinosaurs the T-Rex wouldn't even finish in the Top 10. In fact, if there were heats in the Din-Olympics the T-Rex would be on one of the first planes home, not even winning its heat!

The quickest dinosaurs were:
1. Struthiominus 80 km/hr
2. Ornithomimus 70 km/hr
3. Dromiceiomimus 65km/hr
4. Velociraptor 60km/hr
5. Edmontosaurus 50km/hr
5. Thescelosaurus 50 km/hr
7. Gallimimus 48 km/hr
8. Albertosaurus 40 km/hr

Okay, okay...but how quick are we ? More importantly ... how quick are you?

It is time to find out...

How fast are you?

If a T-Rex did live now, would you and I be able to survive?
Would we able to out-run a T-Rex if we needed to?
How could we work this out?
If we couldn't out-run the T-Rex what else could we do? Outsmart it? Most likely!

Working out fast you are can be done in four ways:
1. having mum or dad or an older sister/brother ride their bike or drive their car beside you while you ran as fast as you can; NOT really a good idea, or
2. timing yourself over a set distance and then converting that time to "speed" or kms/hr, or
3. having someone else measure how quick you are, perhaps by using timing lights, and then calculating "speed" (km/hr), or
4. using a GPS, or
5. guessing (not very good, nor much fun)

Let's measure your time over 20m and then YOU can work out what that means in terms of "speed" or kms/hr.

Then you will know if you could outrun a T-Rex or whether you would have to outsmart it

You've got your time...

By now you should have a time for yourself 'sprinting' 20m or 100m. You may even have times for walking, jogging and striding those distances.

How do you change (convert) your time for 20m (or 100m) to kms/hr (kilometres per hour)?
Easily...

Let's say for 20m you ran 3.45 seconds.
We need to find out how far you ran in each (or one) second. Do this by long division, or by using a calculator.

20/3.45 = 5.8
20metres divided by 3.45 seconds = 5.8 metres per second; or 5.8 metres per each one second

There are 60 seconds in a minute so multiply 5.8m by 60 and you will know how many metres per minute you can run:
5.8 x 60 = 348 metres per second

There 60 minutes in an hour so multiply 348 by 60 and you will know how many metres per hour you can run:
348 x 60 = 20,880 metres per hour

This is a big number. You know that there are 1,000 metres per kilometre so divide 20,880 by 1,000 and you will know how many kilometres per hour you can run (your "speed")

20,880 / 1,000 = 20.88 kilometres per hour

This person can run 20.88 km/hr

Would this be fast enough to escape the T-Rex?
But... how long could you run this speed for?

Compare your result to your friends or classmates.
You may like to calculate the average for the class, or draw a graph showing everyone's results.

What about other animals?

We all know the T-Rex doesn't live now, but there are many animals that do.

Here are some of their speeds to 'check out' ... from slow to fastest.
How many would you beat in a race?

1. garden snail 50m/hour or 0.05 km/hr
2. giant tortoise 370m/hr or 0.37km/hr
3. cockroach 3.5 km/hr
4. rat 10 km/hr
5. polar bear 10 km/hr (swimming)
6. crocodile 14 km/hr
7. honeybee 18 km/hr
8. pig 18 km/hr
9. sea trout (fish) 24 km/hr (swimming)
10. black mamba snake 23 km/hr
11. spiny-tailed iguana 35 km/hr
12. African elephant 40 km/hr
13. rhinoceros 51 km/hr
14. tiger shark 53 km/hr (swimming)
15. polar bear 56 km/hr (running)
16. red kangaroo 65 km/hr
17. greyhound (dog) 66 km/hr
18. racehorse 69 km/hr
19. hare 72 km/hr
20. ostrich 72 km/hr
21. bluefin tuna (fish) 74 km/hr
22. Thomson/s gazelle 80 km/hr
23. pronghorn antelope 88 km/hr
24. racing pigeon 97 km/hr (flying)
25. Mollard duck 105 km/hr
26. cheetah 105 km/hr
27. spine-tailed swift 171 km/hr (flying)
28. peregrin falcon 201 km/hr (flying)

Phewww ... imagine being able to run as fast as some of these animals and birds?

What about other athletes? How fast do they go?