Resistance of the prairie vole (Microtus ochrogaster) and the woodrat (Neotoma floridana), in Kansas, to venom of the osage copperhead (Agkistrodon contortrix phaeogaster).

Prairie vole (Microtus ochrogaster) serum has no anti-lysing or antibody activity against Osage copperhead (Agkistrodon contortrix phaeogaster) venom. However, the serum has an anti-hemorrhagic component, which significantly reduces the size of hemorrhage produced by the minimal hemorrhagic dose of venom and which blocks the minimal hemorrhagic dose at a dilution of 1/8. Woodrat (Neotoma floridana) serum also has an antihemorrhagic component which blocks the minimal hemorrhagic dose at a dilution of 1/32. When compared to similar sized rodents previously tested in Texas, the anti-hemorrhagic activity in the serum of the Kansas rodents is similar. This suggests that venom resistance in prey items of venomous snakes may be more common than thought previously.