Rodenticides are intended to kill certain rodents considered to be pests (rats, mice or shrews). They can have varying chemical compositions, but most rodenticides belong to two specific chemical families :
- anticoagulants which are antivitamin K (Coumarins, Difenacoum). They counteract the effects of vitamin K, which is involved in blood clotting in all animals. This is an accumulation poison. It must therefore be taken in several doses to be able to work. Rodents die 3 to 10 days after the first ingestion;
- convulsants, which cause muscular spasms followed by a coma and then death (pentetrazole, strychnine). The animal dies quickly. The use of convulsants is criticised as it is not always effective. Animals that witness the death of one of their fellow species in the short time after it eats the poison will no longer touch the bait in the future.
Other active substances are less frequently used in rodenticides :
- cardiotoxins which cause death by cardiac arrest (scilliroside);
- cytotoxins, cellular poisons (zinc phosphate);
- hypercalcemiants , when assimilated cause an increase in the concentration of calcium in the body and the formation of crystals (calciferol, cholecalciferol). They are often used to complement anticoagulants.
In order to prevent poisoning other animals, rodenticides can be placed in adapted devices, such as the one shown in the photograph. © Alik, Wikipedia common