Let's Discuss Dietary Requirements for Ball Pythons

[rlditmars]

Some food for thought - especially with regards to differing diets of male and female balls pythons:

Concerning the python diet, Luiselli and Angelci (1998) demonstrated that, although rodents were the main prey type for both sexes, the males differed from the females because they fed significantly more often on arboreal prey (birds), whereas the female diet was based nearly exclusively on terrestrial rodents. The authors hypothesized that these differences were attributable to a higher use of the arboreal niche by males, as also suggested by some incidental observations of males climbed on low tree branches.


So males are more apt to climb and also have adapted to actively hunt and make use of less calorically dense prey types.

There are further studies that confirm this fact (increase arboreality of males vs. females/more varied diet) that were incidental to studies on why female and male ball pythons carry differing external parasite loads.

I would therefore argue that even if 10% were adequate for a female, male ball pythons have been studies as more active hunters that could potentially expend more calories hunting down avian prey that have less calories than mammalian prey.

A large rat is roughly 62% protein, 33% fat and has an energy rating of 6.40 kcal/gram of rat.

A chick has a similar protein profile, but 11% less fat and an energy rating of 5.80 kcal/gram.

However we can probably safely say that wild african songbirds and other ball python target prey items are more active and less fatty than a domestic chick or quail.

Bottom line - even if 10% was a safe prey mass ratio for female ball pythons, it could easily be argued that if may be too much for males.

Skiploder,
You have offered up some great information and some thought provoking questions. I'd like to make a few comments starting with the information above. While this shows that some males will seek arboreal food more often then females, it doesn't offer a reason as to why. Could it be the larger body size of the female makes it less suitable to climbing? Could it be that the male choosing to feed on higher elevated prey leaves more food readily available to the ground constrained females, and much like warblers stratifying in the jack pines, it doesn't depleat the source? It wouldn't seem that the different genders would have different dietary requirements as far as the chemical composition of the food item, so there must be another reason. What ever the reason, it is interesting.

With regard to the 10% to 15% feeder amount, I have always looked at that as a not to exceed number with hatchlings, and have pretty much ignored it all together with regard to larger snakes. On the larger snakes I have just used the snake body diameter > or = prey diameter formula. Regarding frequency I have fed my hatchlings for sale just once a week and have only used the shortened 5 day schedule on those subjects that I was trying to move along a little quicker for my own breeding plans. None of the adults are fed more than once a week unless I have a refusal and it's a matter of either pitching the food item or offering a second to one of the others. But in those rare instances I tend to skip the following week for those animals that take the second item. I only use smalls or mediums for adult snakes. Neither smalls for the males or mediums for the females ever come close to the 15% mark once the animal is about 2 years old. Besides, a 2000 gram female would have a lot of trouble taking down a 300 gram rat, not to mention a 3500 or 4000 gram female.

As far as basking temps and such, I think that you are correct in that a lot of information gets passed along as fact but mainly because it has been reurgitated so often it is believed to be true, like an urban legend. However, I think we all can agree that we should at least try to create an environement that would provide some of the same consistancy of temperature as they would encounter in the wild. Anyone living north of the Mason dixon Line would certainly have trouble with that just using the ambients of their house since most of us like it around 70 or lower depending on your age, gender, or economic situation. So we provide a heat source whether UTH or Basking. And with the heat source is the necessity for regulation since most sources left uncontrolled can injure or worse. I agree that the actual range needed is probably far more wide ranging and forgiving then what gets stressed around here, but again it's easier to say a number than a range when someone is asking what to set the thermostat to. Also, if you tell people there is a wide range they may just think that regulating it is unnecessary which could have dire consequences. So we err on the side of caution. Regarding the natural temps, is there good data regarding the internal temps of the burrows during the daytime hours and the ground temperatures during the night? We can't just go by the average air temps since neither the day or night temps are what the animal is actually in contact with. When they are in the burrow during the day, it is precisely to avoid the daytime air temperatures. Also, if they are wholed up in a termite mound and not too deep in, they could be experiencing a drastically different temp then a snake in a burrow three feet below the ground surface. Same thing at night, since the entire bottom surface of the snake is often in contact with the ground, if the sun has heated that surface up drastically during the day and the evening hasn't allowed for too much radiant loss, the snake may be warmer than the air temp. How many snakes die on the road at night utilizing the surface temps of the asphalt?

All in all I believe your arguments valid, but if we are to change things then we need some good solid data. Also, it should be presented in a way that easily digestible to the layperson since they are going to most commonly be the ones asking. How do you suggest we proceed?