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Swamp wallabies are able to have two simultaneous pregnancies at different stages of gestation, indicating a unique method of mammalian reproduction that leaves them able to be pregnant and lactating for their entire reproductive lives, according to a study published Monday (March 2) in PNAS. The current study confirms what many had long suspected, that swamp wallabies (Wallabia bicolor) can be pregnant in both of their uteruses at the same time, conceiving a second embryo days before the first is born.
As Smithsonian Magazine points out, while the European brown hare (Lepus europeaus) is also able to have overlapping pregnancies, it is confined to a breeding season. The swamp wallaby does not have this constraint, allowing for indefinite pregnancies throughout its reproductive life. Kangaroos and other wallabies also have two uteruses, but they are not used simultaneously.
“Potentially, these animals are always pregnant,” lead author ...
