Obviously food and genetics play a large role in snake growth.
Outside of that does fasting, brumation, breeding, temperature, cage size and lighting play a role in maximum growth potential? If so to what have you observed? Anyone know of scientific research on this?
It’s a very difficult metric to really attribute to anything in specific and a lot of the work to really figure it out is tough to do. Full tests on something like this would involve food trials, constant lab work or biopsy samples, different housing situations and would need a large group of specimens. On top of the years required for it.
Also things can vary greatly between species so that testing could be invalid on a different animal. Some animals require UVB. Others it’s a nice enrichment.
It can be any combination of what you’ve mentioned.
I will say that I feel adequate temps and food are important factors. But the general size they can reach will depend on the parent’s genetics. Stress is also a big factor.
As far as my snakes go…I don’t use light fixtures for my snakes currently. I don’t use any supplements for them. (Ball pythons and Retics)
I have a large male BP that when he was younger was not housed in large enclosure. I unfortunately had to keep him in a pretty small one for a while. He had the right temps and regular meals of a good size. I didn’t let him become obese. The size of the enclosure didn’t seem to slow his growth down at all. He’s around 3kg
A female BP I own is pretty small at 5 years old. She had access to a larger enclosure and adequate food and temps. She still hovers at around 1500g
So in my experience, the enclosure size wasn’t a factor. I’ve never really seen a case where it has been a stunting factor…but there may be severe neglect cases with stunting from enclosures that are much too small.
There’s also the whole can of worms that comes with the Super dwarf or dwarf reticulated pythons. All of the numbers you see getting thrown around as percentage of the locality blood. These numbers are great for tracking the genealogy of the snake like we do for humans. But can mean nothing about the actual size your snake would be.
Typically, the locality mother would mean smaller offspring as she develops smaller eggs. A breeder that crosses the pure locality into a large mainland female will naturally tend towards larger eggs and offspring. Crossing one of those smaller than average male offspring to another mainland can just lead down to again, larger offspring. So knowing about the lineage and a breeder practicing line breeding for size would be best for an idea of how large the snake may get when fed a optimal diet and given adequate heat
Stunting can be a different factor entirely. Trauma can manifest in different ways and the smaller size is definitely one of them. An animal that has spent a large amount of time in an environment that is not ideal in one or more ways can be affected. Stress from overcrowding, aggression from a cohabiting animal, improper diet or vitamins, improper heat or lighting for species that require it can all be factors.
It can almost seem proportionate to the age of the animal and the time spent in subpar conditions.
A smaller and younger animal that is malnourished for many months may not reach the same size as one fed optimally. Especially if that time is a major point of growth in the species.
If it’s a short period of time they may be able to ‘bounce back’ and hit the lower side of the average expected.
An older animal in subpar conditions has most likely completed a majority of their growth, but can still become stunted in the overall way that reptiles are constantly growing. It’s something that we may not even notice happening.
There’s so many little bits and bobs…every animal can be different as well. It’s something we can guess at through personal experiences and what research we have but might never really know the whole thing.
Putting this as an additional comment so it’s a quick answer for the ping.
As far as research goes… I haven’t looked into much outside of what I keep. I don’t know if it’s a topic they’ve looked into much but @socraticmonologue has pulled some good references in the past on other occasions.
Armiyana covered it pretty well, it really depends on a lot of factors and it’s hard to figure out exactly what makes a difference. That being said, while im not sure whether UV lighting affects growth directly, it can affect growth in the sense that it affects appetite and can help a snake eat better. A snake that has eaten consistently throughout its life, is likely gonna get bigger than one that has only eaten sporadically, so that’s something. Same goes for temperature, in the sense that a snake kept at less than ideal temps likely won’t eat and digest as well as one kept in ideal temps. There’s a study that looked at growth rates in python regius kept at ambient temps vs with a hot spot, and they concluded that it didn’t make a difference. One thing i didn’t really like about that study though was that the heat gradient in the ones with a hotspot was only 2c, from 30c ambient to 32c on the hotspot, so there was no nighttime drop or anywhere for them to go below 30c. Most actual keepers keep them with a greater gradient from the mid-20s to the low 30s, so that would’ve been more interesting/telling to observe imo 
Thanks for sharing your thoughts and experience. Very interesting.
I’m fascinated with large constrictors and have often wondered why these well fed retics in captivity don’t typically reach much over 20’. Despite their owners trying their best to achieve a world record sized animal. Other factors of being kept in captivity must be at work. Obesity is surely a killer of a lot of these animals before reaching old age but I wonder if that’s the whole story.
One of my favorite constrictors is the black rat snake. The longest recorded was 8’ 5”. That’s about 1/3 larger than most large adults. It was found in New York which is on the colder end of their range with harsh winters. I’d sure like to know whether it was simply a genetic freak or if something else was going on there.
I’ve always assumed that it’s mainly genetics that determine size, followed up by how much food they’re getting, especially in the most growth-heavy times in their lives. I’ve also wondered if birth (or hatch) size plays some role. I feel like I’ve heard of instances where “runts” in litters/clutches sometimes remain smaller than their siblings.
As far as whether or not brumation plays any role in maximum size…I have no idea. I feel like it wouldn’t? Or if it did, it would slow growth down, since that’s a chunk of time when they’re not eating. But I really have no idea.