The Trollkin Economy 2

Since I wrote the original "Trollkin Economy" I've had a few conversations with various people on the subject. This article attempts to address one concern - the effect on the numbers of trollkin pregnancies. I'll use an assumption that four trollkin are born to trolls for each adult troll in the clan. For details of the derivation of this figure, see the original article (which is still available on this site).

Taking trollkin pregnancies into account introduces new difficulties. Trollpak provides some useful figures - trollkin mature sexually at 15 (by which point they "already will have been a hard-working slave for many years") and generally die before they reach 35. On how many trollkin pregnancies result in live young, we have only the statements that "trollkin... often deliver stillbirths" and "many trollkin are born dead or die shortly afterwards (especially those born to trollkin)."

There are two figures we need to know, but for which we haven't exact figures. These are how long an average female trollkin lives after becoming sexually mature - it seems safe to assume that there are always willing males available! - and how many live offspring the average pregnancies produce. I'm going to make a few other assumptions : trollkin have a roughly 50-50 split between male and female, that trollkin average one pregnancy per year, and that multiple births from trollkin are rare (and can therefore be ignored).

The following table shows the average number of live births to trollkin for each trollkin during its lifetime, based on various values of the unknown figures.

Note that a value of 1 on this table shows a stable population - one with zero population growth. Values below 1 show a declining population, above 1 a growing one.

First, note that even the best line on this table provides for only one quarter of a live birth per year for each trollkin in the community. Taking the Sazdorf as an example, their 190 trollkin would provide around 48 trollkin each year. Compare this to the 240 trollkin that their 60 adult trolls would generate, based on the most optimistic analysis in the previous article. Taking the, I think, more reasonable assumption that only 25% of pregnancies produce live young, then the Sazdorf trollkin would only produce 24 young each year.

It is possible to narrow down the possible numbers a little further. We know that escaped trollkin can form into large swarms. Which would pretty much necessitate a live births in a lifetime figure well above 1. One possibility is that these swarms form around fertile females, whose daughters inherit their fecundity. However, I think it is not unreasonable to take this as an indication that the ratio of pregnancies to live births is at least 25% or so. (i.e. The middle column of the above table.) At that, any group of trollkin that survived for a couple of decades would see its population start to explode.

Trollkin pregnancies would potentially allow a careful troll to increase his trollkin herd, but has relatively little impact on the rarity and therefore value of these creatures.

Plea for comments! I regard this as a first draft, and would greatly appreciate comments, or pointers to information I might have missed. Drop me an e-mail (graham@albionsoft.com).

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