Origin of the domestic dog or the result of natural introgression as the dog expanded across Eurasia. In 2018, a study found a small amount of dog ancestry in 62% of Eurasian wolf specimens looked at, that hybridization had occurred across a wide number of timescales and not just recently, however in contrast there was almost no admixture detected in the North American specimens. There was introgression of the male dog into the wolf, but also one hybrid detected which was the result of a male wolf crossed with a female dog. Wolves have maintained their phenotype differences from the dog, which indicates low-frequency hybridization.
Dog flea of the toxicity of flea treatment products have been scientifically studied and are available online from the Natural Resources Defense Council. Dog flea The dog flea ("Ctenocephalides canis") is a species of flea that lives as an ectoparasite on a wide variety of mammals, particularly the domestic dog and cat. It closely resembles the cat flea, "Ctenocephalides felis", which can live on a wider range of animals and is generally more prevalent worldwide. The dog flea is troublesome because it can spread "Dipylidium caninum". Although they feed on the blood of dogs and cats, they sometimes bite humans. They can