Hybrid (biology) are the mule, a cross between a female horse and a male donkey, and the hinny, a cross between a female donkey and a male horse. Pairs of complementary types like the mule and hinny are called reciprocal hybrids. Among many other mammal crosses are hybrid camels, crosses between a bactrian camel and a dromedary. The first known instance of hybrid speciation in marine mammals was discovered in 2014. The clymene dolphin ("Stenella clymene") is a hybrid of two Atlantic species, the spinner and striped dolphins. Cagebird breeders sometimes breed bird hybrids known as mules between species of finch, such
Donkey burger to eat horse meat; however, since horses were a valuable resource, common people substituted donkey meat and considered it tastier. Donkey burgers became popular towards the end of the Qing dynasty after the Beijing-Hankou railway line was built, as donkeys were no longer needed to transport goods in and out of Beijing. When departing from Beijing, Baoding is the first major city on the Beijing-Hankou railroad. The traditional freight industry was hit particularly hard there, and as a result, donkey burgers became most popular in Baoding. Donkey burger The donkey burger () is a kind of sandwich commonly eaten in