Biliverdin, The Source?
Female dogs have a substance in their womb known as biliverdin, a type of green bile found in the wombs of female dogs. The reason behind the existence of biliverdin in female dogs is still open to debates but its definitely a part of their basic anatomy. Some people say that it plays a crucial role during pregnancy and provides essential nutrients for the puppies in the womb. It might also play a key role in their survival.