If you have a lot of people to question about something, and they have a motivation to lie, consider this clever use of a six-sided die.
If the farmer tossed the die and got a one, they had to respond "yes" to the surveyor's question. If they got a six, they had to say "no." The rest of the time, they were asked to answer honestly. The die was hidden from the person who was conducting the survey, so they never knew what number the farmer was responding to.
Suddenly, the number of "yes" responses to the leopard question started coming up by more than just one-sixth.