Male Alpacas Inducing Uterine Bleeding for Successful Mating and Pregnancy: Unique Reproductive Behavior Discovered

Few animals have as friendly a snout as the alpaca. But that’s not the only thing that makes the animal special. The male is also the only mammal in the world that directly involves the uterus during mating. Biologists from Mount Holyoke College in the US discovered this when they examined the reproductive organs of several female alpacas shortly after they were killed. He showed that the male alpaca pushes his penis all the way into the uterus to fertilize the female.

Lange, dune penis
Before that, animal breeders noticed that the male thrusts his genitals very far into the female. They also knew that the animal has a very long and thin penis, a so-called fibroelastic penis. There are two types: the muscovascular penis as in humans, but also, for example, a horse and a cat. It needs a lot of blood supply to get an erection. A fibroelastic penis, which you find in a bull, ram or pig (and therefore the alpaca), requires much less blood supply and is much longer during erection.

The alpaca’s penis is even more unique: it has a hard cartilage top and is almost spear-like. So the alpaca deposits the sperm directly into the woman’s uterus, instead of entering the vagina first, as other male mammals do.

Bleeding uterus
The researchers came to this conclusion when they went to an alpaca farm where the animals are bred for their meat. They killed several women who were killed shortly after being with a man. In doing this, they discovered that the alpacas were bleeding profusely from various parts of the reproductive tract, from the anus to the cervix and uterus itself. They found the same thing in all the other women who had recently married. And for additional proof, females that had not been visited by a male recently did not bleed at all.

Increased chance of conception
According to the researchers, this is evidence that the males push their penis all the way into the uterus during mating. These women may not like it very much. A hard thrust with the sharp pen not only leads to bleeding, but also to inflammation in the reproductive organs. However, that is good for the chance of success. The way in which the alpacas mate increases the chances of fertilization and a successful pregnancy. The swelling would even help the fertilized egg to implant in the uterine wall.