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0004505Dwarf FortressAnimal Populationspublic2011-04-12 00:412014-07-27 18:25
Khym Chanur 
Toady One 
x86 (AMD Athlon 7550 Dual-Core)Mandriva One2010 (
0004505: Smaller than expected underground vermin populations
Underground vermin like cave lobsters, cave fish and purring maggots have much lower population numbers (as shown via "export map/gen info" from Legends mode) than surface vermin with similar POPULATION_NUMBER tags. This means that most underground lakes will have no fish or lobster in them, and there are only very few purring maggots to catch.
0.40.04, Fixed in 0.40.05?
Issue History
2011-04-12 00:41Khym ChanurNew Issue
2012-07-12 06:30QuietustNote Added: 0023215
2014-07-24 17:15Khym ChanurNote Added: 0027461
2014-07-24 17:17lethosorTag Attached: 0.40.04
2014-07-24 17:41Khym ChanurNote Edited: 0027461bug_revision_view_page.php?bugnote_id=0027461#r10309
2014-07-27 17:53Khym ChanurTag Attached: Fixed in 0.40.05?
2014-07-27 17:56Khym ChanurNote Added: 0027737
2014-07-27 18:25lethosorStatusnew => resolved
2014-07-27 18:25lethosorFixed in Version => 0.40.05
2014-07-27 18:25lethosorResolutionopen => fixed
2014-07-27 18:25lethosorAssigned To => Toady One

2012-07-12 06:30   
I did some tests, examining populations in memory both for subregions and feature layers during a paused worldgen, and while surface populations are mostly within the expected ranges (POPULATION_NUMBER range multiplied by the number of region tiles), feature populations were indeed vastly lower - a cavern covering 29 region tiles contained only 390 naked mole dogs and 351 elk birds compared to the 435-870 and 725-1450 I would have expected. As worldgen goes on, those numbers only seem to get smaller.
Khym Chanur   
2014-07-24 17:15   
(edited on: 2014-07-24 17:41)
Still present in 0.40.04. As an example, purring maggots have the same POPULATION_NUMBER stats as large roaches. In a pocket world there were 25 times as many roaches as maggots, and in a medium world 5.3 times as many.

*EDIT*: Also, the pocket world was 250 old, but the medium world was only 5 years old, so as noted in the previous comment, the disparity might grow the further worldgen goes on.

Khym Chanur   
2014-07-27 17:56   
Something in 0.40.05 has made the problem go the opposite way, so that there seems to be too *many* underground vermin. A 250 year old pocket world had 5 times as many purring maggots as large roaches, while a 5 year old medium world had 14 times as many.

Anyway, *THIS* bug has definitely been fixed.