That split-sided, split-sex cardinal isn't that weird

This split sided cardinal is stuck in Pennyslvania, rather than playing a split-squad game in Florida for St. Louis.

For people who saw, and read about, the interesting cardinal in Pennsylvania? It's just one particular twist on chimerism of various sorts in the animal world, and even split-sex chimerism, whether "split" as with the cardinal or otherwise showing up morphically, while rare, is not THAT rare. Read more.

It should also be noted that this cardinal is so much not THAT rare within its own species that another one was written about five years ago.

Bilateral gynandromorph

This has other implications, as the story notes. In birds, it shows that evolutionary biology doesn't know all the details, such as sexual hormones, etc., of how bird sex develops. In mammals, of course, we know the two sex chromosomes are not the be-all and end-all of sexual identity. We know in reptiles that hatching temperature can influence sexual identity. So, what all happens in birds?

Related to that, speaking of "weirdness" in conception? Meet the "sesquizygotic" twins. They're halfway between fraternal and identical.

The Times piece, at the first link, notes that sexual dimorphism within a single mammal is much less likely than with birds or other orders. But? The sesquizygotic twins should hint to us that it's not impossible.

And, that in turn leads me to the background history of human reproductive developmental problems, and that if you believe in an omniscient monotheistic deity, you have to logically accept that God is the great abortionist.

And, please don't cite "original sin" as the reason for this.