Zinc phosphide in gopher poison is highly toxic. Symptoms of zinc phosphide poisoning include vomiting, fever and diarrhea. This chemical seriously irritates the stomach if ingested, because it produces a reaction when contacting acid and water in the stomach. This chemical is dangerous to birds, fish and other non-intended targets of gopher poison. Zinc phosphide is a crystalline powder that is a grayish or blackish hue. Because this chemical does not build up in a gopher’s tissues and muscles, other animals generally can eat affected gophers without becoming sick.
Strychnine also is a crystalline powder but is white and bears no scent. It is a very strong poison that prevents the chemical that controls the signals of nerves to the muscles from functioning properly. This results in agonizing, harsh spasms that cause the muscles to become fatigued and lead to the inability to breathe, thus resulting in death. Other animals such as birds sometimes come into contact with strychnine and end up dying because a creature’s mucous membranes, such as the intestines and stomach, so easily absorb this chemical.
Chlorophacinone is considered an anticoagulant rodenticide. Several feedings of this are needed to achieve a deadly dose in a gopher. Because it is an anticoagulant, chlorophacinone basically stops the body’s blood from being able to clot, which causes internal bleeding in the target gopher. Chlorophacinone is slow-acting, with rodents who eat it dying in about three days. This chemical also is deadly to other non-target animals such as wildlife or water species.
Diphacinone is a highly toxic chemical when ingested, breathed in or absorbed through the skin. Side effects of this chemical include internal hemorrhaging that leads to death, as the chemical halts the actions of enzymes that enable the blood to clot. In addition, diphacinone contributes to liver damage and eye irritation. Affected gophers experience irregular heartbeats and weakness in their muscles, and they struggle to breathe. Diphacinone is only slightly toxic to birds and fish and does not leak into soil very easily.