[Babase] Questions re. maturity in ranker

Susan Alberts alberts at duke.edu
Fri Sep 29 08:49:58 EDT 2006


>A more general question along the same line:
>There are currently 6 types of rankings:
>
>ADF	Adult Females
>ALL	All group members
>ADM	Adult Males
>ALF	All Females
>ALM	All Males
>FYM	All females and males < 7
>
>Besides enforcing the consistency between ADF and ALF
>as you described above, should we also enforce the consistency,
>say, between ADM and ALM, and, in general,
>ALL with everything else?


Yes; males and females represent a similar situation in that ADM 
should be extractable from ALM in the same way that ADF should be 
extractable from ALF. However, in the case of males unlike females, 
the situation does not arise in which non-adult males ever rank above 
adult males. So, in principle males and females represent that same 
situation but in practice we would not need to disentangle the ranks 
of young males from those of adults.

(Note about the biology: this is because females start - and usually 
complete - their adult rank attainment before they attain sexual 
maturity. There is not much of a size difference between older 
juvenile females and adult females, so it is feasible for older 
juveniles to target adult females; also, maturing females get help 
from relatives in attaining adult rank. So, adult rank attainment 
usually occurs a bit before females are actually physically mature. 
The situation for males is quite different; adult males are about 
twice the size of males that have just attained sexual maturity, and 
newly mature males must go through a substantial growth-spurt before 
they can win fights against adult males; hence, for males, we 
formally designate a period of adolescence -- called subadulthood -- 
which occurs after they have attained physical maturity and are going 
through the growth spurt, but before they have won any fights with 
adult males. Subadulthood ends, and adulthood begins, when they begin 
to rank among adult males. Hence, any male that ranks among adult 
males is by definition an adult male.)


>
>Would it suffice to let ranker users to produce an ALL ranking,
>from which all other rankings are automatically derived (by
>extracting relevant entries and retaining the same relative ranking
>but renumbering to eliminate gaps)?
>

I am not sure that I understand this question so let me know if the 
following paragraph doesn't answer it. I think that you are asking, 
why don't we just create one ranking -- the ALL ranking -- that 
includes all the members in the group, and then just have a rule that 
allows us to extract each of the other rnktypes from this ALL. We 
don't do this because it is actually quite complicated to rank all 
group members together, for the following reasons. (1) There are 
usually many group members, making the ranking task more difficult. 
(2) Dealing with maturing animals  leads to circularities 
(non-transitive rank relationships), because during maturation 
animals do not always climb the ranks in a linear fashion. These 
circularities are brief but can be quite complicated, and the more 
maturing animals you are dealing with the more there are -- and 
combining males and females increases the number of maturing animals 
you are dealing with.

In addition, the biological evidence suggests that within-sex 
rankings are likely to be the relevant rankings from the animal's 
perspective, rather than whole-group rankings.  So, although we have 
all group rankings for some periods of time,, we don't create these 
routinely.

In general, age-sex classes rank as follows from highest to lowest: 
Adult males, subadult males, adult females, juvenile males, juvenile 
females. However, as I mentioned above, animals mature in a 
non-systematic fashion and as they grow and climb ranks, brief 
circularities result.
-- 
--------------------------------------------------------------------------------------------------------------------------------------
Susan Alberts, Department of Biology, Duke University, Box 90338, 
Durham NC 27708
919-660-7272 (phone), 919-660-7293 (FAX)


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