Making plaster casts of mammal tracks

Tapir footprint (CC image by Christian Ostrosky)

This idea distinctly appeals to me, but I don't have any first hand experience to offer you yet.

I've been looking at 'Mammals of Britain: their tracks, trails and signs,' by M.J. Lawrence and R.W. Brown. Not only does it have pictures of individual footprints (quite easy to find on the internet), it has good illustrations of stretches of tracks - so you can see differences between front and rear paws, and see clues to the way the animal was moving at the time. Please do come and borrow the book (I've seen it cheaply secondhand too). If you've got the prints of something tiny, you can cast a length of them like this. Or you can just cast a single pawprint.

I like this chap's video very much - he's making a cast of a grizzly bear print near a glacier in Alaska, and he makes it look very simple. He surrounds the print with a dam of dirt to contain the plaster, but you can also use a strip of cardboard or a slice from a plastic bottle (as used by the British Badger Watching Man). I like the way he minimises mess by mixing the plaster in a plastic bag. And it's also instructive to see how he digs around the plaster to remove it without breaking it. You need to be patient and leave it to set for at least 15 minutes (the air temperature will make a difference, it could need longer).

His plaster looks quite thick - Lawrence and Brown suggest 'the consistency of evaporated milk' (if you even know what that is), or I've read 'thick cream'. But this is probably something you'll get to grips with as you gain experience.

You can allegedly buy plaster of paris at the chemist, or they would surely also have it in art shops (probably at a more expensive price). The Badger Watching Man mentions decorating filler... you could experiment.

The type of surface will also influence your success - Lawrence and Brown are very dubious about good prints from sand and silt - but then the chap with the grizzly bear print seemed to do very well on silt.

I also liked the grizzly bear chap's advice to scratch details into the back of the cast while it's setting. This wouldn't have to be all the what/where/when/who details - but a permanent connection to those details in your notebook would be good. You can always write on the cast afterwards when it's set.

The Mammal Society sell a kit that enables you to take inky footprints of animals that walk through a tunnel. That might be an alternative idea - it apparently works well in obtaining records of hedgehogs.

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