Image of the Day: Bat Embryos Seba's short-tailed fruit bat (Carollia perspicillata) embryos collected in the wild at about 50, 65, and 70 days of development (left to right) ...

Bats are one of evolution’s most remarkable creations. They stand apart as the only mammals capable of true flight, using their thin, flexible wings to glide, hover, and dart through the night sky.

Lab-grown structures with the potential to develop into fetuses should be defined — and regulated — as embryos, some researchers say. It is time for a redefinition of the human embryo, a team of ...