CONJOINED ANIMAL TWINS

Most people have heard of conjoined twins, or "Siamese twins," as they are sometimes called.  These twins are joined together somewhere on their bodies, and they often share internal organs such as livers or brains.  The reason these twins are called Siamese twins is because back in the 1800s there was a really famous pair named Chang and Eng Bunker, who came from the country of Siam, which is now called Thailand.  These twins traveled around with some circuses, and lots of people paid money to see them.

Anyway, the same thing that happens to people sometimes happens to animals, and the result is conjoined twin animals.  Except that we don't hear about it as much because (1) conjoined animals might not even be able to get out of their mom and be born, or (2) they might get born, but they are born dead, or (3) if they are born alive, they usually can't survive for very long, especially not in the wild.



No one is totally sure how conjoined twins happen, but there are two theories.  The older theory is that the egg gets fertilized in the womb, and then it splits in two, but it doesn't split completely.  This theory is called fission.  The newer theory that people now think is more correct is that the fertilized egg splits completely, but then the stem cells in the twins start looking for similar stem cells (because this is what stem cells do), and they end up growing parts of the twins back together.  The name of this theory is fusion.

Then there's another kind of weird twin, and it's called a parasitic twin.  This type of twin happens when one of the twins is dominant, and the other twin stops developing.  So the twin that is a parasite ends up having only certain parts, like maybe legs or a head or something, and it is completely dependent on the other twin that got fully developed.  Which is why it's called a parasite.

Okay, so that's enough explanatory stuff.  Now we need to look at some pictures.  I tried very hard to find photos that are real, true photos and not ones that are photoshopped, but it's difficult to tell the difference sometimes, so I'm sorry if I got fooled.

These two rattlesnakes were joined at the neck -- if you can say that a snake has a neck.  Some people found them at a construction site in Arizona and brought them to the Arizona Sonora Desert Museum.  The museum asked a veterinarian named Dr. Jim Jarchow to separate the snakes, so he did surgery on them.  He thought they were just joined by soft tissue, but it turned out that the top two vertebrae were also joined.  So he cut through the bones, too, and now the snakes are two separate snakes.

Here are two Nile Tilapia that live in an aquarium in Bangkok, Thailand.  They were 8 months old when this picture was taken.  They have found a way to make their situation work just fine.  The smaller fish goes around upside-down, looking for food, while the bigger twin protects him.

A man in Arkansas found two young barn swallows that are joined at the hip by skin and maybe also by muscle tissue.  It is very rare to find conjoined birds because of course they would not be able to fly, so once they got old enough to need to fly around and get their own food, they would die.

The rest of the pictures I found are of what I think are parasitic twins, and not really conjoined twins.  There are several examples of animals that have two heads.  The scientific word for having two heads polycephaly, just in case you ever need to know.

This cat is named Lil Bit, and when he was born, the vet told his mom that he would probably not survive.  But she really wanted for him to live, so she fed him every 15 minutes from an eye-dropper.  I'm not sure when she got any sleep,  because she did not explain that part.  Anyway, after 2 or 3 months of feeding him like that, she started him on real cat food.

Lil Bit has two mouths, two noses, and four eyes.  Vets think that he may also have two brains because one face can go to sleep while the other one is awake, and the two pairs of eyes can blink independently.  Both faces eat and breathe, and one face can sneeze without the other face sneezing.  Lil Bit's mom says "When he purrs it is like he is purring in stereo."










Here are a couple of examples of snakes with two heads:

The rest of the examples I found are mostly of animals with extra legs, which is a condition that I think would make it hard to walk very well, unless you were really well coordinated.

I looked for some pictures of conjoined dogs.  I couldn't find much, but I did find this puppy fetus that was preserved in a jar.

Also I found a dog with six legs.

And then, finally, I found what I was looking for!  Aren't they cute?