Wikipedia actually has a fairly good resource on this: http://en.wikipedia.org/wiki/List_of_animals_displaying_homosexual_behavior
I haven't looked into the sources in detail, and I'm sure the definition is nuanced in each case, but it's a good starting point and it's fully referenced. As for maintainence and ultimate explanations of homosexuality in nature... A more interesting hypothesis than the 'inclusive fitness' argument (in my opinion) is that genes coding for homosexuality are maintained through inheritance in female lines: those which manifest in males as homosexual orientation are manifest in female relatives to increase fitness. There's some (relatively anecdotal) evidence supporting this: http://www.medicaldaily.com/articles/10287/20120613/homosexuality-gene-mother-reproduction-evolution.htm Iain - - - - - - - - - - - - Dr. Iain Stott Environment and Sustainability Institute University of Exeter, Cornwall Campus Tremough, Treliever Road Penryn, Cornwall, TR10 9EZ, UK. - - - - - - - - - - - - http://www.exeter.ac.uk/esi/ http://biosciences.exeter.ac.uk/cec/ On 28 March 2013 03:40, Warren W. Aney <[email protected]> wrote: > Wayne and Ecolog-L, > I recall reading some time ago about a hypothesis that homosexuality in > populations is or may be a response to heightened population density, > implying that it is an innate stratagem to reduce reproduction while > maintaining adult productivity. Anyone know anything about this? > > Warren W. Aney > Tigard, Oregon > (503) 539-1009 > > > -----Original Message----- > From: Wayne Tyson [mailto:[email protected]] > Sent: Wednesday, 27 March, 2013 11:53 > To: Warren W. Aney; [email protected] > Subject: Re: [ECOLOG-L] Expedition notice and question > > Warren and Ecolog: > > As a stock-farmer's son, I have seen plenty of what appears to us to be > homosexual behavior among, for example, cows and bulls and ducks and dogs, > but I have never witnessed actual penetration, nor have I witnessed any > cases where bulls eschew cows in favor of sex with bulls. Homosexual in the > sense that it occurs in humans is the center of my interest, and anything > that is relevant to that question is of interest to me, including > anecdotes. > > "Mounting" of other bulls has long been considered dominance behavior, and > this occurs in humans who consider themselves heterosexual, as appears to > be > > the case with dogs. > > Your point is well made about the continuum; Alan Watts once wrote an > article entitled (as I recall) "The Circle of Sex." That, or anything else > I > > have read, does not address my intentionally restricted question. > > WT > > ----- Original Message ----- > From: "Warren W. Aney" <[email protected]> > To: "'Wayne Tyson'" <[email protected]>; <[email protected]> > Sent: Wednesday, March 27, 2013 10:30 AM > Subject: RE: [ECOLOG-L] Expedition notice and question > > > > Wayne, I once had a beef cow that refused to mate with a bull -- she did > > lactate and help nurture another cow's calf. The cow may have been > > homosexual or asexual. I've heard livestock owners say that cows > > frequently > > display homosexual behavior (mounting other cows) but a cow exhibiting > > excessive homosexual behavior including avoiding bills is usually sold > for > > slaughter. > > As I understand it, in nature (including humans) there is a wide and > > continuous spectrum of sexual behavior ranging from pure heterosexuality > > to > > bisexuality to pure homosexuality, and this range of behaviors is further > > modified by a varying continuum of sexual intensity from hypersexuality > to > > asexuality. > > > > Warren W. Aney > > Tigard, Oregon > > (503) 539-1009 > > > > > > -----Original Message----- > > From: Ecological Society of America: grants, jobs, news > > [mailto:[email protected]] On Behalf Of Wayne Tyson > > Sent: Wednesday, 27 March, 2013 10:32 > > To: [email protected] > > Subject: [ECOLOG-L] Expedition notice and question > > > > [NOTE:] I will be on expedition (with a stop at the National Native Seed > > Conference in Santa Fe NM on April 10) until the two weeks at the end of > > April and the first week of May, then gone again beginning the 2nd week > of > > May until around May 24. I will not be checking email during those > > periods, > > but will respond to as many email messages as possible during those > > hiatuses. A third expedition following those is likely, but the period of > > hiatus is iffy.] > > > > Here is my parting question. Please feel free to post it on other lists. > > > > Re: Homosexuality in animals other than Homo sapiens. We know that > > homosexual behavior occurs in other species in some forms (Bonobo > > chimpanzees [Pan paniscus], for example), and we know that hermaphrodites > > of > > some species fertilize each other simultaneously. But my question is in > > which species other than humans, does EXCLUSIVE homosexuality, especially > > in > > the form of pair bonds, occur? > > > > WT > > > > I'll pick up my answers in late April. If I have time, I may be able to > > respond to some today. Please respond on-list, and not to me personally. > > > > > > > > ----- > > No virus found in this message. > > Checked by AVG - www.avg.com > > Version: 10.0.1430 / Virus Database: 2641/5707 - Release Date: 03/27/13 > > >
