Dog pawprint

Making casts of animal tracks

Scientists working in the field make copies of things that are delicate or difficult to move. Animal footprints are a perfect example. Taking a cast of animal tracks is easy, and it can help you identify the animal that made them. Read on to find out how...

You will need:

  • a bottle of water
  • plaster of Paris
  • a plastic freezer bag
  • a frame to place around the footprint (such as a cookie cutter or a circle of card)
  • scissors
Animal track

An animal track in the mud. The frame around it will hold the plaster mix we're about to pour in.

Preparation

Before you leave the house to hunt for footprints, make sure you have the right amounts of plaster and water with you. Check the plaster of Paris packet instructions.

Measure out the plaster powder into the plastic freezer bag (wear a dust mask to avoid breathing in the fine powder).

The hunt begins…

The best footprints are made in soft mud, so check for animal tracks near water or in muddy woodland. If you can’t find any wild animal tracks, you can practice making casts of a pet’s footprints.

Making your cast

Pouring the thick, smooth plaster mix into the animal pawprint

Squeezing the plaster mix into the animal track.

  1. Once you’ve found a footprint, carefully remove any twigs or leaves. Try not to disturb the footprint.
  2. Gently push your frame into the ground around the footprint. This should create a wall to contain your plaster mix.
  3. Pour the water into the plastic freezer bag containing the plaster powder. Hold the top closed and squish the plaster and water to mix. Do not touch the mixture directly: it gets hot.
  4. When all lumps have gone and the mixture looks like thick cream, use the scissors to cut off a small corner from the plastic bag. Carefully pour the plaster into the footprint.
  5. After 15-20 minutes your plaster should be dry enough to move. You can tap it to check. Carefully prise the plaster cast off the footprint.

After 24 hours your cast should be fully dry. You could varnish or paint it.

Finished cast of an animal pawprint

Our finished cast. Can you guess what animal made this paw print?

Identifying animal footprints

The size, shape and pattern of tracks are clues to what animal made them. Try looking them up in a library or online, or asking your local wildlife society. 

If you can’t identify the tracks, contact the Museum's Identification and Advisory Service at the Angela Marmont Centre for UK Biodiversity. The team will do their best to help.

A version of this article was originally published in Wild World, our magazine for kids.