Nature is a cruel but also wondrous mistress. It gives us the scourge of all weekend lawn mowers - the fire ant hill - but soothes the sting (get it?) with butterflies alighting on well-landscaped lawn flowers.
Sometimes Nature is both cruel and wondrous at the same time. Take two-headed snakes, for instance. These very real, though rare, reptiles are fantastically weird and exciting to see, though they lead short lives and are gone much too soon.
Dicephalic Parapagus | Craniopagus Parasiticus
The condition of two heads side by side on the same torso is called Dicephalic parapagus (and two heads with a regular and also a vestigial torso is Craniopagus parasiticus). In the wild the condition appears in only one out of 100,000 snakes, while in captivity it is slightly more often, with one in 10,000. Outside of snake enthusiasts, two-headed snakes aren't seen very often because they don't live very long. Most are stillborn, or die shortly after hatching (or being live-birthed, depending on the species of snake).
Why do these weird little creatures live such short lives? That's due in part to the fact that often one head is less formed than the other. Or both heads will be deformed in ways that make it difficult for the snake to survive. They may not be able to breathe or eat correctly, which makes living past infancy almost impossible.
Two Headed Snake Behavior
It's interesting to note, though, that two brains are the norm for two-headed snakes (and sometimes they have two hearts). And not only that, but each head will have its own personality. This will lead to one head being dominant over the other head. It will make most of the decisions about where the snake goes, how it behaves, when it will eat and drink, etc.
Can you imagine being the submissive head, and having to follow along with whatever the other demands? It would take "sibling rivalry" and arguing to a whole new level. But as the less dominant head is often the least formed as well, it's probably better off following the other head's lead.