Step right up! Behold a Two-headed Snake!

Clients of mine who breed corn snakes recently had this very unusual baby hatch out of an egg in their incubator, a two headed snake! The hatchling appears to be a pair of conjoined twins which is very rare indeed. We occasionally see two-headed snakes hatching and it is usually a random event; a freak coincidence causing fusion during early embryonic development known as polycephaly.

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In any case, most two headed snakes look to all intents and purposes like a single snake body with two heads side by side on a single neck. This hatchling however is conjoined much farther down the body, just above the level of the heart so it appears from X-rays I took that each head has a separate throat, windpipe (or trachea) and oesophagus that carries food to the stomach. This most likely resulted from fusion of monozygotic or identical twins during the early stages of development within the egg. It was extremely difficult considering the tiny size of the creature to obtain good diagnostic quality X-rays especially as the animal was conscious and difficult to keep it still to take a shot, so the exact anatomy is still unclear. I didn’t want to risk anaesthetising such a fragile, tiny creature just for interest sake to look at its anatomy but from what I can make out it seems like there is one dominant animal with relatively normal anatomy and the other has fused just above the level of the heart. I think there is a single heart, stomach and other abdominal organs, although there is a lot of air so there may be two lung spaces, unusual in that snakes usually only have a single functional lung.

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Other problems that are evident are that the spine is kinked in a few places, which may cause problems down the line, although plenty of minor kinked snakes do lead perfectly normal and pain free lives. The good news is that the little snake has now eaten its first meal, and appears to be doing well. Whether it survives long term is still unknown however. There could be invisible problems we are not yet aware of. If it does survive it would be very interesting to perform more advanced imaging such as MRI to determine the anatomy, but of course this is all academic as there would be no benefit to this little snake, or should I say snakes! Surgical correction is not possible and would result in the death of one or both animals. The main concern in the near future is whether quality of life can be maintained.

More information on the underlying causes can be found here:

http://genetics.thetech.org/ask/ask299

http://news.nationalgeographic.com/news/2002/03/0318_0319_twoheadsnake.html

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