do babies really eat their twin in the womb? if so, why does that happen?


do babies really eat their twin in the womb? if so, why does that happen?

In: Biology

The short answer is: they do not. The slightly longer version is …I don’t actually know how to make this answer longer. They just don’t. But I am really curious what on earth gave you the impression that they did?

Its a saying, they aren’t literally eating the other baby. But in some twin pregnancies not enough nutrients are being delivered to both. The body may divert to providing adequate nutrients to one baby at the expense of the other. One lives and the other withers and does not.

In addition to what /u/Darth_Mufasa said, sometimes two embryos can stick together and merge into one. Depending on what stage of development this happens at, the result may be conjoined twins, or a single outwardly normal looking “chimera” who looks like one person but contains cells with both their and their siblings’ DNA.

My mom had a cyst removed in her 30’s that had hair and teeth in it. They said they thought it was a twin that didn’t thrive.

Not humans, however there is a case of sand tiger sharks.

“Female Sand Tiger Sharks have two wombs, and each of them produces many eggs. The eggs hatch while still inside the womb, and the Sand Tiger embryos soon develop sharp teeth and start killing and eating their brothers and sisters and any unfertilized eggs in the womb, until there is only one embryo left alive in each womb.
As a result, the mother only gives birth to two pups (the last survivor of each womb), and since they fed abundantly in the womb, they are already quite big when they are born, around one meter long!The Sand Tiger shark is therefore the only fratricide in this list that starts killing their siblings before being born; at the moment of its birth, it is already an experienced killer. This brutal survival strategy is known as intrauterine cannibalism, and was discovered in 1948 when a scientist, who was probing the womb of a Sand Tiger Shark, was bitten in one hand by one of the embryos! Although intrauterine cannibalism has been reported in other species of sharks, including the Great White Shark and even the Basking Shark (a placid, harmless plankton-eater as an adult), these feed only on unfertilized eggs while in the womb. The Sand Tiger Shark is the only shark known to cannibalize other embryos in the womb.”