Why study dinosaurs or fossils? 

No human can tell us what life was like on earth longer than mere thousands of years ago from their own personal experiences or even history.  Beyond that we have no idea, unless we look at the evidence or clues left behind by past living things such as creatures, plants or rocks.

Skeletons tell us about a creatures size and weight,  where the muscles for movement were, how it reproduced, defended itself or attacked etc.  Maybe by comparing it, to other similar skeletons or the rocks it was found in, you will know the creatures age when it died.  A skull can tell us what it ate,  possibly how big its brain, sensory and other glands were.  Limbs tell us how the creature moved, walked, lumbered, sprinted, flew etc, or whether it had flippers for swimming. The shape of the feet show whether it climbed or could hold things, how it may have defended itself and how it may have mated.

Photographed at Western Australia Museum

Can you think of anything else the skeleton or bones can tell us about that creature?  How about how it died. Bones and teeth can show where they have been eaten away by infection or were broken.  Fossils tell us how a creature or plant fitted in with the whole history of creatures and plants.  Or perhaps when it became extinct.

Microfossils help date rocks by their presence in rocks.  Certain tiny creatures such as plankton only lived at a certain time so then you know how old the rock is due to which species of plankton is found in the rock.

Fossils also tell us what the temperature could have been at that time and how life adapted or failed to adapt to the changes in climate etc.

What is a fossil?

Any remains, trace, or imprint of a once living plant or animal that has been preserved in the Earth's crust since some past geological or prehistoric time; loosely, any evidence of past life including pollen, insects in resin, seeds, birds nests, beehives, tracks, bones etc that has outlasted the natural processes that would normally destroy it.

Not many bone fossils of dinosaurs have been discovered in Australia, but there are many other fossils.

  Photographed at the Western Australian Museum

A lot of different things had to happen all at the right time for an animal or plant to become a fossil.  But  what if you were out walking along a creek or you were digging a hole for a bush toilet and you came across bones.   How can you tell if you have found fossilised bones?

- Fossil bones are heavier than non fossil bones as stone or minerals replaces some or all of the actual bone matter.
- Almost all fossils are found in sedimentary rock such as clay, mud, sand or silt that have become hardened and compressed over millions of years such as limestone caves. This type of sediment is usually found where there has been lakes, rivers, swamps and oceans in the past even if there is no water there now. See our section on 'How rocks are formed.'

- Is what you have found a solid imprint of a footprint, bone or plant in rock and not just dry hard mud? Sometimes this is all that remains from the animal or plant as it has completely rotted away.  Lakes and river beds can dry out over the summer months here in Western Australia.  If an emu was to walk over the muddy rivers edge its footprint may set there until the following rains.  A fossil imprint wont wash away over one season.  

- Fossils can be ancient tracks or frozen bodies.  In this photograph you can see the foot print.  This gets covered by the ocean every tide and does not wash away.  It has survived normal natural destruction of time that a footprint would not normally survive, so it is a fossil.

Photographed in Broome Western Australia

- Have you found a bone that shows minerals mixed in and around parts of the bone like quartz, opal or limestone?  Often as the bone decays minerals fill in the gaps.  These harden in the shape of the bone or plant.  Sometimes the whole bone has gone and it is totally made up of quartz or some other mineral.  It may even change the colour of the bone or fossil.
- The fossil may not be found all together in one place due to previous streams or floods taking part of the body away to another place.  Or perhaps it was half eaten.

- Not all fossils are buried as the rocks may have weathered and eroded by wind or rain or effected by earthquakes or humans.  They can be found underground, in cliffs, on top of mountains, inside rocks, trapped in ice (I've done my research, I have seen "Ice Age"), caves, under the ocean floor, in mud, or just lying in a paddock or even your own backyard. (Better ask mum before you dig up her flowerbed).
- Don't forget insects can be fossils too.  If you find an insect trapped in resin like the red gum from the marri tree you may have found a fossil.  And so can shells, petrified wood and eggs be fossils.

 However not everything that we may think is a fossil ends up being a fossil, less than 1% of all animals will become a fossil.   Sometimes minerals accumulate inside sedimentary rocks.  Go here to learn a lot more about this http://www.amonline.net.au/factsheets/geodes.htm 

Geode and Thunder Egg.

  Photographed at the Rockingham Environment Centre on Saftey Bay Rd