“Y” Chromosome Day

Today is the greeting card industry’s celebration of the “Y” chromosome in human beings. Also known as “Father’s Day,” it is a day, in my family anyway, where I am invited to take my kids out to lunch or dinner. Which got me to thinking about ratites. We’ve written about them before, in our series about bird sex as well as the Cassowary poem.

There are four new Rhea chicks at the Smithsonian National Zoo in Washington, D.C. Here is a photo of the Dad and some of the chicks, taken by Mehgan Murphy of the National Zoo.
Rhea chicks

Rhea fathers raise Rhea chicks. The Rhea species depends on the father Rheas to do this, otherwise it would not survive: Rhea mothers are given to eating their offspring and it is the fathers who protect them. The dads also build nests, incubate the eggs, and take care of the babies for their first six months on the planet. Perhaps the polygamous males are feeling guilty about all the females they court each mating season. But they don’t need to feel guilty; as soon as the female lays her eggs, she is off after other males.

Native to South America, they are named after the Mother of the Gods, Rhea. Rhea, in Greek mythology, was the daughter of the sky (Uranus) and the earth (Gaia). She married Cronus and was the mother of Demeter, Hades, Metis, Hera, Hestia, Poseidon, and Zeus, in that order. Cronus, you will remember, had a guilty conscience. He had castrated his father Uranus and imprisoned him. (Yes, he was both husband and brother of Rhea but that is OK for gods. They don’t have to worry about chromosomes and inbreeding.) Anyway, Uranus and Gaia tell Cronus that one of his sons is going to do to him what he did to Uranus. But Cronus is resourceful, as Rhea gives birth to each of their children, he swallows them alive. (Perhaps that is where the male Rhea got his guilty conscience and leads him to protect his chicks.) Eventually, Rhea gets tired of going to all the trouble of bearing young, just to have her husband/brother eat them so she arranges to hide young Zeus and gives Cronus a rock wrapped in swaddling clothes to swallow rather than a young god. Zeus eventually grows up and the rest, as they say, is history. Cronus is given an emetic and regurgitates all the other children. There is a war, Cronus loses and accounts of his end vary. Most are not happy, although in one Zeus makes him the king of Elysium.

Why Paul Heinrich Gerhard Möhring, the German physician, botanist and zoologist who named Rheas, chose the name is unknown. Möhring wrote a book called Avium Genera, published in 1752. It was one of the earliest attempts to group and classify birds. Traces of his organizing efforts are still visible in modern groupings of birds. Which is remarkable, considering that he knew nothing at all about “Y” chromosomes.


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One Response to ““Y” Chromosome Day”

  1. Mad Bluebird Says:

    In NEW ZEALAND the KIWI the national emblem of the country the MALE will sit on the large egg for up to 70 days till it hatches and the kiwis wings are too small to allow it to fly so its nocturnal and despite its rather mild appearence they are very fierce fighters

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