I spent a junior high school days, which is the susceptible age, in the turn of the 21^st century and became interested in the keyword "extinction" that was well featured at that time. I thought that "breeding" is necessary to avoid the extinction, and aspired to becoming a researcher on the conservative reproduction. Breeding is "a beautiful chain of life". This is common to all animals. Animals have adapted to the environment over a long period of time, and have evolved species-specific reproductive patterns. I'm studying from viewpoints of behavioral science, cell biology, reproductive endocrinology, etc. on “what changes will occur in their breeding when habitat and breeding environment change?" as a main theme.