Abstract:Abstract: Horizontal gene transfer (HGT) means the movement of genetic material between species other than via vertical transmission. HGT may cause rapid coevolution in populations, convergent evolution among different species, and inheritance of novel genetic traits, making it one of important driving forces in evolution of species. In the past, HGT studies were mainly focused on prokaryotes and plants, but in recent years, phenomena of HGT in animals gradually attract attention. To further understand current status of research on HGT in animals, examples and relevant evidences of HGT in animal groups are presented, the reliability of the evidence is evaluated, and authentication methods for HGT are briefly described. This may help better understand the significance of HGT in animal evolution.