|All of the embryos in alphabetical order.|
Embryos are necessary for creating prehistoric mammals. To create an embryo, mammalian DNA (both prehistoric and modern) must be put in culture vats along with some sort of fuel. Obtaining your first embryo gives you the "Ouch!" achievement. Once created, embryos can be injected into vanilla Minecraft pigs, cows, sheep, or horses (quagga embryos can only be injected into horses). These animals become pregnant with the animal that corresponds to the embryo. The DinoPedia can be used to monitor the growth inside the pregnant mammals. The baby will be born after approximately 100 seconds.
There is no wolf, ocelot, mooshroom, villager or bat embryo as of yet, and the chicken embryo has been removed and been replaced by a cultivated chicken egg.