King, for almost a decade my undergraduate and graduate research used the California mountain kingsnake as a study organism. One of my three research areas revolved around heritability of phenotypic characteristics; which in turn required large numbers of breeders. Like all graduate research, time is limited, so I had no choice but to power-feed the young and the adults.
Over the course of the study, multiple trends began to reveal themselves:
1. Wild-caught snakes during the first year of breeding directly following their year of capture never egg-bound and had small clutches (2-6).
2. With each additional year breeding within our lab clutch size increased, but so did egg retention.
3. Larger females (i.e., fatter ones) tended to retain eggs at a higher rate.
Lastly, whenever any individual would die in our lab a subsequent necropsy was performed. Wild-caught snakes had very little fat in their body cavities, while some long-term captives and most captive-born stock had body cavities filled with fat (from the beginning of the body cavity to their cloaca). We even had several females die during brumation because their fat began to go necrotic, leading to sepsis and death (UC vet diagnosis).
What we determined was that the captive animals were not being given a variable diet, but instead were being maintained completely on rodents. The mice we fed our snakes were high in fat and much lower in calcium than the natural diet of the mountain king that included a high number of low-fat lizards. The issue with introducing lizards as a dietary supplement into our breeding colony was the high probability of introducing pathogens into our colony. Freezing only kills a small majority of pathogens, so we felt that the risk was much greater than the reward (yes, we sacrificed the long-term health of the animal for the short term reward of more fecund females).
Mountain kings aren't corn snakes, but their highly similar. Both species are opportunistic with respect to prey, and both are active foragers. Many of my non-feeder hatchling corns (in fact almost 100%) will take a pinky that has been scented with a western fence lizard. That shows me that they have a major predisposition for lizards when young. I'm sure that prey preferences change in the wild as corns mature (from lizard to rodent), but I'm also positive that most adult corns won't pass up a lizard meal as an adult if the opportunity arises.
So, long story short, power-feeding high-fat food items like our captive-reared mice can only lead to a shorter life for our breeders. Our corns will rapidly build up fat within their bodies because of their diet, but also because almost all the enclosures we keep them in are too small for them to get adequate exercise; meaning atrophy of muscle and an accumulation of more fat. Corn snakes are long, thin snakes in the wild, with very few ever reaching the gargantuan proportions we see in our captive collections. Only adult snakes that have been around for a long time begin to really reach the girth that our captive snakes do. Furthermore, even though we can breed snakes at two years, they probably don't ever become reproductive until their fourth year in the wild (especially females). Evidence from our mtn king study from our study sites show that most mtn kings don't lay their first clutches until their fifth to sixth year of life!
Seeing that keeping corns is purely a hobby to me, I have no desire to sacrifice the health of my animals for the short-term gain of more fecund, quicker clutches earlier in life. All of my snakes are kept thin (not starving or rail-thin, but thin) and are fed to ensure that breeding in females takes place realistically in their fourth year. Some breed in their third year, but I try not to have that happen.
Next time you have an adult corn pass on you that you've power-fed, do a quick and informal necropsy on it. I guarantee you you'll find a high amount of fat within the body cavity; a condition that a wild corn of that age wouldn't have. The few that have passed on me that I've necropsied have all been like that. Some even had their hearts completely surrounded by fat, with many of the livers appearing to consist of more fat than functional liver tissue.
Oh well, you asked! Haha.
