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This Marsupial is the Only Animal That's Always Pregnant

posted by Fnord666 on Wednesday March 04 2020, @12:18PM   
from the why-male-wallabies-smile-a-lot dept.

upstart writes in with an IRC submission for Bytram:

This marsupial is the only animal that's always pregnant

Most mammals can become pregnant several times during adulthood, but for the vast majority, there is a healthy pause after each birth, while mothers nurse their babies. For some, of course, it's normal to only have one or a couple offspring in a lifetime.

But swamp wallabies, small hopping marsupials found throughout eastern Australia, are far outside the norm: New research suggests that most adult females are always pregnant. As described in a paper published March 2 in the Proceedings of the National Academy of Science, the animals typically conceive one to two days before giving birth.

Like all marsupials, swamp wallabies (Wallabia bicolor) give birth to tiny, immature babies that crawl to a special pouch where they nurse on their mother's milk. Some marsupials, like kangaroos, can mate and conceive about a day after birth, but not before, says Brandon Menzies, a study co-author and researcher with the University of Melbourne.

These wallabies are the only animal, besides the European brown hare, that can become pregnant while already pregnant. But the hares have distinct breeding seasons and are not continuously pregnant most or all of their adult lives, as female swamp wallabies are.

The study is important because "understanding the biology and endocrinology of reproduction in any species may have valuable lessons for human reproduction too," says David Gardner, at the same university, who wasn't involved in the paper.

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Original Submission

• Re:Cats Re:Cats (Score: 2) by Grishnakh on Thursday March 05 2020, @03:49AM (1 child)

  by Grishnakh (2831) on Thursday March 05 2020, @03:49AM (#966833)

  Humans can also become pregnant while pregnant. It's exceptionally rare

  I was about to post something about this too. However, if you're talking about what I'm thinking of, it's an extremely rare mutation some women have where they have 2 uteruses (uteri?), each connected to its own single ovary and fallopian tube. I don't think it's possible for a normal human woman to become pregnant while already pregnant.

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• Re:Cats (Score: 2) by Booga1 on Thursday March 05 2020, @08:54AM

  by Booga1 (6333) on Thursday March 05 2020, @08:54AM (#966895)

  The Wikipedia article seems to be a bit skeptical about whether "superfetation" is possible, but Time magazine reports [time.com] 10 cases of happening.

  There have been only 10 recorded cases of the phenomenon, dubbed superfetation. In Grovenburg's case, she became pregnant first with a girl (whom she has decided to name Jillian) and then two weeks later with a boy (Hudson). The babies have separate due dates — Jillian on Dec. 24, Hudson on Jan. 10.

  Another report is of a surrogate pregnancy [insideedition.com] where the woman's natural cycle still happened and the woman ended up carrying two babies from separate parents. Of course, that took some man-made interference.

  “They were in separate sacks” in the uterus, Jasper said. “One baby came out black-and-white and one baby came out Chinese,” he said. Allen is white. Jasper is black.

  The two babies are also not the same age, Jasper said. His and Allen’s child was about three weeks younger than the other infant.

  Superfetation can occur when a pregnant woman continues to ovulate. Jasper said he and his partner did copious amounts of research before finding reports about the rare occurrence. Doctors later confirmed it in their case, he said.

  Parent