Examples of reverse-phase high performance liquid chromatography (RP-HPLC) chromatograms from different venoms included in the study. A. Crotalus scutulatus type II venom with MTX but lacking snake venom metalloproteinases (SVMPs); sample 4311, nr. Rodeo, Hidalgo Co., NM. B. Crotalus scutulatus × viridis, hybrid containing MTX and SVMPs; sample 4687, nr. Cotton City, Hidalgo Co., NM. C. Crotalus viridis, typical venom lacking MTX but containing SVMPs; sample 4590, nr. Animas, Hidalgo Co., NM. D. Crotalus atrox, typical venom lacking MTX but containing SVMPs; sample 4594, nr. Benson, Cochise Co., AZ.