[Cazador]

Many times when two different species interbreed, their offspring are inviable. They normally die before delivery (if the female is even able to conceive), but sometimes the offspring are born. Sometimes they have genetic abnormalities that lead to an early death, but more often the offspring are simply infertile. The reason is because many times different species either have a different number of chromosomes, or there are enough different genes that their chromosomes don't merge properly after the sperm fertilizes the egg. In the wild, hybrids are often ill adapted for the lifestyle of either parent and are less competitive (fit) than pure bred individuals. Yet for snakes, I think the viability of hybrid offspring would vary from cross to cross. For example, if a species adapted for warmer, more humid areas, would hybridize with a species from a mountainous or more arid area, then the offspring wouldn't be well suited for either environment. Sometimes weird things happen in captivity that wouldn't happen in nature, though hybrids do sometimes occur.