Python

My first look at Python was an accident, and I didn't much like what I saw at the time. It was early 1997, and Mark Lutz's book Programming Python from O'Reilly & Associates had recently come out. O'Reilly books occasionally land on my doorstep, selected from among the new releases by some mysterious benefactor inside the organization using a random process I've given up trying to understand.

One of them was Programming Python. I found this somewhat interesting, as I collect computer languages. I know over two dozen general-purpose languages, write compilers and interpreters for fun, and have designed any number of special-purpose languages and markup formalisms myself. My most recently completed project, as I write this, is a special-purpose language called SNG for manipulating PNG (Portable Network Graphics) images. Interested readers can surf to the SNG home page at http://www.tuxedo.org/~esr/sng/. I have also written implementations of several odd general-purpose languages on my Retrocomputing Museum page, http://www.tuxedo.org/retro/.

I had already heard just enough about Python to know that it is what is nowadays called a "scripting language", an interpretive language with its own built-in memory management and good facilities for calling and cooperating with other programs. So I dived into Programming Python with one question uppermost in my mind: what has this got that Perl does not?

Perl, of course, is the 800-pound gorilla of modern scripting languages. It has largely replaced shell as the scripting language of choice for system administrators, thanks partly to its comprehensive set of UNIX library and system calls, and partly to the huge collection of Perl modules built by a very active Perl community. The language is commonly estimated to be the CGI language behind about 85% of the "live" content on the Net. Larry Wall, its creator, is rightly considered one of the most important leaders in the Open Source community, and often ranks third behind Linus Torvalds and Richard Stallman in the current pantheon of hacker demigods.

Pythons are heavy-bodied constrictors, meaning they rely on their size and strength to capture and kill prey by crushing. All python species are non-venomous. They are for the most part terrestrial, and of brown, black or green colour (for camouflage). A notable exception is the green tree python (Morelia viridis), which is considerably more slender than it's con-generics, arboreal and of a truly striking green colour.

The Burmese (Python molurus) and Reticulated pythons (P. reticulatus) are truly gigantic snakes, measuring up to 32 feet in length and weighing more than 300 pounds. They are not, however, the largest snakes on the planet. That honour falls to the Anaconda (which is a member of the boa sub-family, Boinae), which has been measured at 37 feet in length and must have weighed well over 500 pounds (Anacondas are considerably more robust than pythons). Despite their large sizes, these two species are often kept in captivity quite successfully, given their relaxed temperament and the fact that they only feed two to four times per year.

Not all python species are as large as these giants, however. The Anthill python (Antaresia perthensis) remains under two feet in total length as an adult, and the common Ball python rarely exceeds four feet in length. This latter species is very often kept as a pet, and is particularly well known for its docile character and tendancy to curl into a ball when held (thus the name).

Some pythons, like the Reticulated, display unusual reproductive behaviour for snakes. While other oviparous snakes lay their eggs and then depart, the female of this species will remain on her nest, without eating, to protect the eggs from predators during incubation. Some have hypothesized that this is due to the slow growth rate of the species and their low lifetime reproductive output. By remaining on the nest, a female Reticulated python, which will only have a couple of clutches in her lifetime, increases the odds that one of her offspring survive to reproductive age (biologists call this her fitness).

Finally, it should be noted that the wonderful and horrific stories often heard about savage, human killing snakes are urban myths and have little basis in reality. I say little basis because there are documented cases of pythons attacking humans, but in suburbia rather than the jungle. Almost all attacks can be considered due to poor husbandry or frightful stupidity on the part of the Homo sp. rather than the Python sp. And, if you ever see a picture of a boy ingested by a python circulating on the internet, know that it is a fake.

Taxonomic information

The genera Antaresia, Apodora, Aspidites, Bothrochilus, Leiopython, Liasis and Morelia are restricted to Australia, New Guinea and Indonesia, while the genera Calabria, Python, are found in Africa and Asia. The monospecific genus Loxocemus is native to Mexico, and is only tentatively placed in the Pythoninae.

Species list1

    * Genus Anataresia, the children's python2:
          o A. childreni, Children's python
          o A. maculosa, Spotted python
          o A. perthensis, Anthill python
          o A. stimsoni, Stimson's python
    * Genus Apodora:
          o A. papuanus, Papuan python
    * Genus Aspidites
          o A. melanocephalus, Black-headed python
          o A. ramsayi, Woma
    * Genus Bothrochilus:
          o B. boa, Bismarck ringed python
    * Genus Calabria:
          o C. reinhardtii, West-African burrowing python
    * Genus Leiopython
          o L. albertisii, White-lipped python
    * Genus Liasis, the water pythons:
          o L. fuscus, Brown water python
          o L. mackloti, Macklot's python
          o L. olivaceous, Olive python
          o L. sawuensis, Sawu python
    * Genus Loxocemus:
          o L. bicolor, New world python
    * Genus Morelia
          o M. amethystina, Scrub python
          o M. boeleni, Boelen's python
          o M. Bredli, Centralian python
          o M. carinata, Rough-scaled python
          o M. clastolepis
          o M. kinghorni, Australian scrub python
          o M. nauta
          o M. oenpelliensis, Rock python
          o M. spilota, Carpet python
          o M. tracyae
          o M. viridis, Green tree python
    * Genus Python
          o P. anchietae, Angolan python
          o P. curtus, Blood python
          o P. molurus, Burmese python
          o P. natalensis, South African rock python
          o P. regius, Royal, or Ball, python
          o P. reticulatus, Reticulated python
          o P. sebae, Central African rock python
          o P. timorensis, Timor python