I took a class in casting prints of wildlife from Mitch Johnson and Peter Callen of Pathways. The class was really good, and amid puns of “come to the casting call” and “someday my prints will come” attendees learned a lot about getting good casts of wildlife prints!
We were using 30-minute set (or so) plaster. Two scoops of the plaster, with enough water to make it runny, works well for casting a single cougar print. I’m guessing that a bear print would need up to 4 scoops. While Pathways has made up kits, what is needed is a plaster or dental casting powder, some water, and a straw or brush to clean up the print before casting. An acrylic spray can be used to hold the print, but on sandy prints, it is just as likely to spray the print away as to coat it.
Enough water to make the plaster runny allows it to get into all of the parts of the print. When filling the print, the pad and toes need to be captured and connected with one another so the print is solid. Condition of the soil also matters; sandy soil is more fragile, and muddy soil can be too watery to keep shape. Although we were practicing with prints that were set out in different soils, we did come across an actual bobcat print as shown below.
Unfortunately, it was too disturbed to get a decent casting.
In general, the steps in casting are to find the print. Try to get a sense of which direction the animal was going it and how old the print is. Ageing the print can be done by figuring out if the latest rain was before or after the print was left – knowing the soil can be helpful with that. Photograph the print in-situ, preferably with a reference nearby (either a ruler or a coin or other common object). Get a geo-point. Then, make the casting. A flat shovel or flat-headed tool can help to remove the print once the casting has set. It may also be helpful to note the weather on the day the print was cast. In this case, it was a beautiful fall day!