by Whit Gibbons

June 12, 2016

Gender has been a contentious social issue in the United States for well over a century.

The 19th Amendment to the U.S. Constitution passed by Congress in 1919 and ratified by most states in 1920 was necessary to establish the point that women should have the right to vote. The topic was a long-lasting and controversial one considering it was initially introduced to the U.S. Congress in 1878 and was still being contested in 1922 when the Supreme Court unanimously ruled in favor of the amendment. Equality of the sexes in the workplace continues to be debated, and recent transgender issues have introduced yet another wrinkle.

Looking at gender distribution patterns in other animals probably won't provide any insights for humans. However, looking at what other animals have to deal with, some similar and some different from the human condition, gives a fresh perspective on our own situation. In some parts of the animal kingdom, the gender issue could easily become confounded, at least by human standards, because the diversity of sexual differentiation among species is immense. The array of patterns is fascinating. For some species, determining how to balance male-female rights would be baffling, especially if they had to deal with voting rights.

A common difference between the sexes in many species is body size. In some species, including humans, adult males reach larger sizes on average than females. Such is true for African elephants, tilapia and American alligators. In even more species, however, females get noticeably larger than males. Female size dominance occurs in black widow spiders, slider turtles and red-tailed hawks.

Numerous hypotheses have been proposed to explain why the sexes have evolved to be different sizes among different species. Those having larger males generally have social systems in which males engage in physical combat or display with other males of the species. Contests are typically fought for possession of resources, including access to females. One relatively reliable attribute of species having female size dominance is that larger females produce more offspring on average than smaller ones. As with American citizens, despite the difference in average body size between the sexes, each individual, male and female, in such species should get one vote.

One trait of many animal species that could lead to dissension of whether "one critter, one vote" should apply is a frequently observed feature of some animal populations. That is, the sex ratio is nowhere near equal. For example, garter snakes in Manitoba have a notable excess of males. Should females get twice as many votes as males because they are so outnumbered? Or should a heavily male-dominated society let females vote at all?

In the other direction, the Brahminy blind snake, an Asian species now naturalized in Florida, has a population sex ratio that should cause no problem with proponents of gender equality. These tiny snakes that are the size of earthworms are all females. A mother Brahminy blind snake lays unfertilized eggs that hatch into little female snakes that are genetic copies of themselves. The 19th Amendment would be unnecessary. Either everyone votes or no one does. With regard to gender politics, this might be the most harmonious society imaginable.

In some animal species differential size and number of the sexes would pose no problem for another reason, because each individual possesses both male and female reproductive organs. For example, when two earthworms mate, each provides sperm to fertilize eggs in the other. Each earthworm would naturally get two votes in an election. That might be handy when trying to decide whether to vote for Candidate A or Candidate B. Just vote for both. But imagine how confusing the issue of sexual harassment or gay rights would be among earthworms.

Determining voting rights for the sexes could clearly get very complicated among many other animal species compared to humans. But the issue of where any of them go to the bathroom never has caused a problem.

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