Kangaskhan (Kangaskus parentis) is a rare Pokémon species known to be only one gender (female), and are known to reproduce asexually through parthenogenesis. Male Kangaskhan went extinct around the 1800s because of poaching, as it was believed their ears had magical healing properties.
Kangaskhan is the only Pokémon species known to have a large pouch in which the baby (currently classified as a Kangaskid) develops until it is old enough to evolve into an adult. Hatching a Kangaskhan baby in captivity has proven challenging, unexpectedly Kangaskhan hatched from eggs outside of the pouch already have a baby. Since in the mother’s pouch the baby develops from an embryo and not an egg, it is possible that the hatching (and consequent evolution into an adult) triggers the birth of a new baby for some reason.
Baby Kangaskhan take quite a while to evolve into adults, and each female produces multiple embryos inside their pouch. Embryo develop one at a time, and only once the baby evolves into an adult the next embryo starts developing into a baby. For these reasons finding a Kangaskhan without a baby is very rare.
This unique development makes Kangaskhan possibly the only Pokémon known to have two baby stages (although many consider the embryo stage the same as the baby).
by GebF