Yes, there are rare cases of snakes being born with two heads, a condition called polycephaly. Polycephaly is an anomaly that can occur in many animal species, including snakes, where an embryo splits into two heads during development. This results in a two-headed snake with a single body.
What causes two headed snakes?
The exact causes of polycephaly are not fully understood, but it is thought to be due to both genetic and environmental factors. In snakes, polycephaly occurs when a developing embryo begins to split into identical twins but the process is incomplete. This can result from issues like:
- Genetic mutations leading to abnormal development
- Incubation temperatures that are too low or too high
- Disruptions or damage to the egg during embryonic development
The incomplete splitting of the embryo leads to a snake with two heads sharing one body. Each head has its own brain, mouth, and senses, but the body organs like the heart, lungs, and digestive system are shared.
How common are two headed snakes?
Two headed snakes are extremely rare. They make up only a tiny fraction of snake births, estimated to be about 1 in 100,000. The anomalies that cause polycephaly make it difficult for two headed snakes to survive long after birth. Most captive two headed snakes live only a few months, though there are exceptional cases of longer lived specimens lasting several years.
In the wild, survival is even more challenging for polycephalic snakes. The difficulties of having two heads coordinating movements and competing for resources means two headed snakes in natural environments often die shortly after birth. But occasionally, wild two headed snakes like rattlers and garter snakes have been discovered and photographed before perishing.
Do two headed snakes occur in certain snake species?
While polycephaly is rare overall, certain snake species seem predisposed to producing two headed offspring more frequently. Some snakes where two headed specimens are more common include:
| Snake Species | Notes |
|---|---|
| Ball pythons | The most commonly captive-bred two headed snakes, possibly due to genetics and breeding practices. |
| Milk snakes | Prone to anomalies like polycephaly due to inbreeding. |
| Rattlesnakes | Several wild two headed rattlers have been found, reasons unclear. |
| Garter snakes | One of the more common wild species to exhibit two heads. |
The higher rates of polycephaly in these species may result from more inbreeding depression, or genetic and environmental factors specific to these snakes. But overall, two headed individuals can unpredictably appear in any snake species.
How do two heads work on a single snake body?
Having two heads allows the snake to see in two directions at once and increases their field of vision. But coordinating the movements of two heads on one body is difficult. The two brains may compete for control of the body, each head trying to move in a different direction resulting in contradictory motions. Eating is also made challenging with each head drawn to food sources.
The two heads are capable of independent actions like eating, tracking motion, and sensing stimuli. Each has its own thought processes and behaviors that may differ. One head often becomes dominant and controls more of the body’s movement. Both mouths are fully capable of biting prey or humans, injecting venom in poisonous species.
Can two headed snakes survive in the wild?
Survival is extremely difficult for polycephalic snakes born in the wild. Competing brains makes hunting, feeding, avoiding predators, and other survival tasks hard. And having two heads is a major disadvantage for a predator that relies on stealth and camouflage to ambush prey. The difficulties of surviving and competing usually mean two headed wild snakes die quickly after birth.
Can two headed snakes reproduce?
There are no known cases of two headed snakes reproducing. Their life expectancy in captivity is usually too short for them to reach sexual maturity. And even if they did, coordinating mating with the shared body would be difficult. Each head may even try to mate with a different partner. For breeding, the snake heads must be in agreement and work together.
If a two headed snake did produce offspring, the babies would likely be normal one headed snakes. The snake would have to pass on two copies of the mutated gene responsible for polycephaly for it to occur in the progeny, which is improbable.
Famous examples of two headed snakes
While most two headed snakes perish quickly, a handful have survived for many years in captivity and become famous. Some remarkable examples include:
- Theodosia – Lived over 20 years as a pet and zoo attraction. A black rat snake with two fully formed heads.
- Tom and Jerry – Captive born king snake that lived 8 years under expert care in San Diego.
- Brave Dave and Weak Dave – Pair of heads belonging to an albino hognose snake that survived 5 years in captivity.
- Bonus Joe and Regular Joe – Polycephalic plains garter snake found in wild in Kansas that lived over 3 years in captivity.
These exceptional snakes became local celebrities during their time on display and reveal that polycephaly, while extremely rare, does not preclude a long life given optimal care.
Key facts about two headed snakes
- Polycephaly from embryonic splitting causes rare two headed snake births.
- Survival is difficult, most die shortly after birth.
- Certain species like ball pythons see higher rates.
- Each head has independent thoughts, senses, and behaviors.
- Coordinating shared body motion is problematic.
- Reproduction has never been recorded.
- A few captive snakes have lived over 20 years.
Conclusion
While an intriguing anomaly, two headed snakes are extremely improbable to encounter in the wild. Their severe survival challenges and short lifespans make these snakes scientific curiosities that only occasionally last long as captives under highly controlled care. But the few polycephalic snakes that have endured demonstrate the remarkable resilience of life even under such burdensome mutations.