>--- 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From popularizations and maybe out of date--the size difference is 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. > there are two schools of thought 1) females are the bigger because of reproductive issues. They must feed a brood--take bigger prey, they must incubate the clutch--bigger = more body heat. that said, they also believe 2) that it is a historical artifact of early avian divergence. But the first theory gets more respect.