Proceedings of the Vertebrate Pest Conference

Four adult female Botta's pocket gophers (Thomomys bottae) that had survived many normally potentially lethal doses of strychnine alkaloid in another experiment (Lee 1986) were examined further. These individuals freely consumed 0.5% strychnine bait, and 3 of them also 1% strychnine bait, for long periods without dying, whether or not nontoxic alternate bait was present. After 1 gopher (#5) was taken off its 1% strychnine wheat diet for 44 days, it lost its physiological tolerance to strychnine and died the first day when again exposed to a free choice of nontoxic and 1% strychnine wheat. It consumed only 7 mg/kg of strychnine before dying, whereas another gopher (#42) was able to survive on a mean daily consumption of 275.8 mg/kg of strychnine in a no-choice situation over a period of 28 days. This is almost 40 times the lethal dose of the other animal.