Dragaera

Dzur and Sex

Mon Jan 26 15:39:05 PST 2004

--- Philip Hart <philiph at SLAC.Stanford.EDU> wrote:
> 
> 
> On Mon, 26 Jan 2004, Jerry Friedman wrote:
> 
> >
> > --- Philip Hart <philiph at SLAC.Stanford.EDU> wrote:
> >
> > > (which is what I would pararectally expect for an artificially
> evolved
> > > species).
> > >
> > > In case someone hasn't mentioned it, differences in size between
> male
> > > and female members of species is apparently strongly inversely
> related
> > > to the degree of monogamousness (monogamosity?).
> >
> > Monogamy?
> >
> > Among birds, this is a strong relation but not a universal one.
> > In birds of prey, females are bigger than males--very noticeably, in
> > falcons and bird-eating hawks--but they're monogamous.
> 
> Fascinating - is there an evolutionary just-so-story?

>From popularizations and maybe out of date--the size difference is
so males and females don't compete with each other for prey.  Last
I heard, no one knew why females should be the bigger sex in both
raptors and owls.

> Hmm, birds have xx
> males and xy females, right?

Right, though when the female has the small chromosome it's called
a w.
 
> Also I guess one should distinguish between monogamy,
> pair-bonded-for-life, and not-sleeping-around-at-all.  I vaguely thought
> that some p-b-f-l birds turn out to have a surprising degree of
> adultery.
> In fact I thought p-b-f-l actually had turned out to be really rare,
> even
> in birds, except for albatrosses or something, so ignore me.

I think raptors are monogamous for a year, but not for life.
Recommended reading, even for people who aren't bird geeks: _Red-Tails
in Love_, by Marie Winn.

> Anyway, it should be noted that jhereg (and maybe orca?) are dimorphic
> in
> the hawk mode.  SKZB is really on top of his universe.

Though it should also be noted that the sex differences are smallest
in scavengers.

On the other hand, the most intelligent birds are often said to be
ravens, which are roughly jhereg-sized opportunists and scavengers.
So maybe packing human-like intelligence into a brain the size of a
rednut wasn't *just* a cruel joke.  (Recommended reading: _Mind of
the Raven_, by Bernd Heinrich.  Very heartwarming, like _Red-Tails
in Love_.  There are noticeable similarities between raven and
jhereg "person"alities.)

Jerry Friedman

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