Kevin Hit 3.

[WrongPython]

First of all, happy birthday Kevin! That's a very handsome bredli right there.

Now y'all better strap in, because all this talk about snake growth means that you just wandered into my academic field! So pardon me while I put my academic nerd hat on, grab my lecture materials, and deliver my knowledge of snake growth and thoughts on why captive males may be smaller than their wild counterparts for all those who are interested.

The short: Snakes have indeterminate growth and will continue to grow over time using the energy they have left over after basic metabolic costs and reproduction are addressed. The demands of birth and egg-laying means females typically have more mass compared to a male of the same length, though this difference can go away or even reverse if male competition for mates is a factor. Captive males may be smaller than their wild counterparts because it's more convenient for keepers and we're capable of controlling their growth.

The no-so-short: So, let's start at the very beginning with the basics of snake growth. Almost all snakes have something we academics like to call indeterminate growth. In other words, snakes will continue to grow throughout their lifetime, and don't have a "maximum size" that they will stop growing at. If they're alive and have the energy they need to grow, they'll do so.

What determines the amount energy snakes have to grow? Well, like most animals, snakes gain their energy by eating food. So, the more food a snake manages to eat, the more energy they have to burn. Most animals use their energy for three main purposes: basic metabolic costs, reproduction, and growth. Basic metabolic costs are the costs of keeping your body running -- they're the energetic costs of breathing, pumping your heart, digesting your food, powering your brain, and the like. Animals will use the energy they gain to address basic metabolic costs before anything else. Once basic metabolic costs are taken care of, an animal will then direct their remaining energy towards growth or reproduction. How an animal directs their spare energy between the two depends on their circumstances.

In the case of snakes, physically mature individuals will likely put a considerable portion of their spare energy towards reproduction. This means bringing their reproductive organs back online, producing gametes, and -- in the case of females -- growing eggs and babies. The physics of egg production and pregnancy require a larger snake compared to one that simply produces gametes, which is why female snakes are typically bulkier and more massive compared to males of a similar size. However, this sexual dimorphism can break down when male combat is a factor -- the larger male typically wins the fight -- or even reverse if the pressure of competition is high enough. Any energy that's left over after reproduction can be put towards growth.

Individuals who are incapable of reproducing -- whether it's an immature juvenile or a lone adult that doesn't receive the cues they need to trigger mating behavior -- will put their spare energy towards growth instead. For juveniles, this means eventually reaching physical maturity (so they can reproduce) and becoming less of an easy prey item. For otherwise mature adults, this could mean increasing their reproductive fitness (ie. getting larger to better fight rivals or lay more eggs) or their overall survival fitness (ie. maybe bigger's just better in the habitat where you live). Since they don't have to worry about reproduction and have comparably lower metabolic costs, a juvenile's growth rate will normally be much greater than an adult's. However, decades of incremental growth and the occasional glut of food (ie. a massive intake of energy) means adult snakes are still capable of growing quite a bit! If I had to guess, those 12-13' coastals are very old snakes and very successful hunters.

So with all of that being addressed, why are captive male snakes typically smaller than their wild counterparts? Well:

In captivity you'll see larger females but the key there seems to be that large males cost more to feed and house so they are "kept" at a certain size. Larger females are desired because they are supposedly mature earlier and can breed and produce more based on their size

Gio pretty much hit the nail on the head. Captive males' smaller size may be a factor of our ability to control snakes' food intake and, by extension, the amount of spare energy they have to grow. Larger females are necessary to produce more young, but smaller males can still get their job done while being easier and more economical to keep. It's almost a no-brainer for a breeders. I'll also add that small breeder males are putting more energy into reproduction compared to a "pet" male of the same age, and thus have less spare energy left for growth.

Gio's also made good observations on why smaller males may be better breeders than smaller males in captivity. Size does not equal reproductive fitness. A young, rapidly grown male may not yet be sexually mature despite being "the right size." Furthermore, it's likely that power-feeding levels of rapid growth disrupt a snake's proper bodily functions and stunt their proper development, which leads to poor breeding performance. Snakes will mature when they're ready. A slow-grown male will be smaller than a rapidly grown male at your average age of sexual maturity, but they'll probably have had more balanced growth overall, which makes them better breeders.

I'm going to stop myself for now. Apologies if this came across as too lecture-y for people -- I wound up teaching this semester and I'm In That Mode. If anybody is interested in the real nitty-gritty of snake biology, I'd highly recommend getting a copy of How Snakes Work: Structure, Function, and Behavior of the World's Snakes by Harvey B. Lillywhite. It's a dense, grad school-level read, but it sounds like some of you might be up for that!

[End lecture. Class dismissed]