spudtater | Bizarre biology

1. Cyclopia

Holoprosencephaly is a rare and often fatal birth defect caused by a mutation in a gene which codes for a protein known as, of all things, sonic hedgehog. It can also be caused by consumption of the plant Veratrum californicum, supposedly on the fourteenth day of pregnancy.

Holoprosencephaly causes a variety of problems, all of which are caused by the failure to properly divide structures along the midline of the head. The brain may be improperly divided into lobes, causing retardation and epilepsy. More visibly, though, it causes facial abnormalities.

The most extreme of facial abnormalities is called cyclopia. This is where the face fails to create two seperate eye sockets. The result of this can vary; either two eyeballs are present in a single wide socket, or just one eyeball forms, or, most bizarrely, a single eyeball forms, but with two irises and pupils. In addition, the nose is either absent, or takes the form of a odd sort of proboscis that forms above the single eyeball.

Cyclopic offspring almost always miscarry or are stillborn. However, there was a case recently of a cyclopic kitten, Cy, that survived an entire day. A picture can be found here. (Warning: not exactly graphic, as such, but somewhat disturbing.)

If you really must see more images of this disorder, you could try typing "cyclopia" into a google image search. I strongly advise against it, though; it will return, among other things, pictures of human babies and foetuses with this condition.

2. Parthenogenesis

Parthenogenesis, meaning literally "virgin birth", is the process of producing an embryo without the help of a male. There are several plants that use this technique, as well as aphids and bees. More bizarrely, birds such as turkeys have been known to reproduce like this, albeit very rarely.

The case I find most fascinating, however, is that of the Virgin whiptail lizards, a group of several related species in the Cnemidophorus genus. Native to Mexico, all these species appear to have arisen through crossbreeding of similar species, leading to a sterile, polyploid offspring. (Polyploid = having more than two sets of chromosones.)

Though the lizards are sexually sterile, they can reproduce by parthenogenesis. The mechanism through which polyploidism enables parthenogenesis in these species is unknown (or at least Wiki is drawing a blank), but the result is in an entire species of fertile females, without a single male among them.

Lack of males, however, does not stop them wanting to have sex. When estrogen is low, a lizard will play the role of the male, and mount other lizards. When estrogen is high, the other lizards will mount her. Even though no actual mating takes place, it has been shown in the lab that this behaviour produces hormones that lead to higher fertility.

3. Circus freaks

Finally, if you are interested in human oddities, you may wish to peruse the pages of phreeque.com. Yes, it's a real honest-to-goodness internet freak show — but to its credit it treats its subjects with respect and compassion, describing not only their disabilities, but also how they overcame or dealt with these. It also defends the freak show of times past, pointing out how the performers gained a livelihood from it, rather than having to exist on the charity of others.

By far my favourite page is that of Jean Baptista dos Santos:

'It was not dos Santos' three legs that most excited medical men, but his double genitalia. He possessed two functioning penes and three scrota, the outer two of which each contained a single testis. Dos Santos claimed that the central scrotum had also contained a pair of fully-formed testes, but that these had retreated into his abdomen when he was ten years old. Wrote the photographer C.D. Fredericks, creator of the only known photograph of dos Santos, in 1865, "...the sight of a female is sufficient to excite his amorous propensities. He functionates with both of the penes, finishing with one, then continues with the other." He urinated and achieved erections with both penes simultaneously.'

Words fail me.