That Reptile Blog – Reptile, Amphibian and Exotic Pet Care and Information

The 53 species in the family Boidae are an amazingly diverse group of snakes that have colonized habitats ranging from rainforests to deserts, in countries as diverse as Canada and India. Among them we find treetop dwellers, aquatic species, confirmed burrowers and generalists equally at home in farmland, savannas, desert fringes and forests. I’ve had the good fortune of studying Anacondas, Rosy Boas and others in the wild, and remain fascinated by all.  Please be sure to post some thoughts about your favorites below.

Classification and Terminology

The family Boidae is divided into 3 subfamilies. Most boas are placed in the subfamily Boinae. The ten Sand Boas of southern Europe, Africa and Asia, the Calabar Ground “Python” and North America’s Rubber and Rosy Boas are classified in the subfamily Erycinae. Ungaliophiinae is comprised of the Oaxacan, Isthmian and Panamanian Dwarf Boas.

The term “boa” usually refers to the Common Boa. A short “first name” is applied to others, i.e. Rough-Scaled Boa, Rainbow Boa, Malagasy Tree Boa, Pacific Boa.  Read More »

The massive Green Anaconda (Eunectes murinus) is one of the world’s best-known snakes.  I had the good fortune of participating in the first long-term study of this species in the wild (please see this article), and zoos have kept and bred them for decades.  But its relatives, despite being large, impressive creatures, have not been well studied.  One, the Bolivian Anaconda (E. beniensis), was only described in 2002, and its natural history remains shrouded in mystery; we know only a bit more about the Dark-Spotted Anaconda (E. deschauenseei).  The Yellow Anaconda (E. notaeus) regularly appears in zoos and the pet trade, but field studies are lacking.

Dark-Spotted or De Schauensee’s Anaconda, Eunectes deschauenseei

Although described as a distinct species back in 1936, the habits of the Dark-Spotted Anaconda remain unstudied, and it rarely appears in public collections.  While working with Green Anacondas in Venezuela, I tried to arrange a side trip to an area where they were reported to live, but was unable to arrange it.  A review of the acquisition records at the Bronx Zoo, where I worked for many years, revealed that several specimens were believed to be this species, but none were definitely identified as such.  I recently poked around among stored Green Anacondas in the collection of the American Museum of Natural History (courtesy of a colleague there) and hope to return to check on Dark-Spotted Anacondas.  Although widely separated in range from the Yellow Anaconda, many taxonomists hold that the two are closely related. Read More »

The subject of giant constrictor attacks upon people always brings out wild claims.  While working with Green Anacondas in Venezuela, I tried to track down 2 reports of human predation, but was unable to prove or disprove either.  I recall reading several well-authenticated accounts in old issues of Herpetologica, and sadly, have first-hand knowledge of a tragic incident involving a captive Burmese Python in NYC.  But a recent article on the Agta people of the Philippines took me very much by surprise – from 1939-1973, 26% of all Agta men, and 2% of the women, had been attacked by Reticulated Pythons!

Living with Giant Pythons

The article, published in a recent issue of The Proceedings of the National Academy of Science of the USA, was co-authored by a prominent herpetologist and a scientist who lived with the Agta people, in a remote region of the Philippines, for 24 years; some impressive photos are included as well (please see abstracts, below).  Read More »

The Burmese or Asian Rock Python, Python molurus bivittatus (or Python bivittatus, see below) is one the world’s longest snakes, and vies with the Green Anaconda for the title of heaviest. Florida’s introduced Burmese Pythons are often in the news these days for causing ecological havoc and occasional human fatalities.  However, not much attention is given to this massive serpent’s life in its natural habitat.

Description

Matched in size only by the Reticulated Python and Green Anaconda (the heaviest of which I’ve encountered tipped the scales at 215 lbs.), this stoutly-built snake may reach 25 feet in length, although animals of 18-20 feet are considered large.

“Baby”, a huge female in residence at Illinois’ Serpent Safari Park, is said to measure 27 feet in length and weigh 403 pounds (please check out this video).  A specimen under my care at the Bronx Zoo exceeded 300 pounds in weight and consumed 30-40 pound pigs with little difficulty.  The large albino python has been on exhibit at the Brooklyn Children’s Museum for over 20 years.

The ground color is yellowish-buff or tan fading to cream along the flanks, with large chestnut-brown blotches throughout.  There is an arrow-shaped mark on top of the head.  A variety of color morphs are common in the pet trade.

Most taxonomists now classify this snake as a distinct species, rather than as a subspecies of the Indian Python.

Range

The Burmese Python ranges widely throughout South and Southeast Asia, including northeastern India, Myanmar, southern Nepal, Thailand, Laos, Cambodia, Vietnam and southern China (including Hainan and Hong Kong).  Introduced populations are established in Florida and Puerto Rico.  Records from Sumatra and Borneo are likely misidentifications.

The closely-related Indian Python, Python molurus, is found in India, Pakistan, Sri Lanka and Nepal.

Habitat

This snake is extremely adaptable, but requires the presence of a permanent water source.  It inhabits wooded grasslands, swamps, open forests, river valleys and rocky foothills.  Farms, suburbs and the fringes of urban areas are frequently colonized.

Natural Diet

All pythons have thermo-receptive sensory pits along the upper jaw that assist in locating warm-blooded animals at night.  Prey is killed by constriction, with death resulting due to compression of the lungs and heart failure (via pressure on the heart and blood vessels).

The range of animals taken is vast.  Adults usually concentrate on monkeys, deer (Muntjac, Chital, Hog Deer, Sambar Fawns) wild pigs, Peafowl, Red Jungle Fowl, small cats and other carnivores, and large rodents.  Toads, fishes, porcupines, pangolins and monitor lizards are listed as prey in several older field reports.

In his classic book The Giant Snakes (a “must read” for all snake fans!), Clifford Pope reports that a Leopard measuring 4’ 2” long was taken by an 18 foot Burmese Python and that a young captive consumed 61 pounds of rats in one year, thereby adding 34.5 pounds to her weight.  The largest meal of which I’m personally aware is a 50 pound pig taken by a captive in theUSA.

Humans and Domestic Animals as Prey

Burmese Pythons, Reticulated Pythons, Green Anacondas and African Rock Pythons are the only constrictors known to have killed people.  The reported cases concerning Burmese Pythons involved large pets attacking their owners; in several cases, escapees have attempted to consume children.  The other species mentioned have, on rare occasions, preyed upon people in natural (free-living) situations.

In addition to such tragic encounters, pythons also run afoul of people by feeding upon domestic animals.  I was once called to Prospect Park, Brooklyn to deal with an escaped pet snake that had consumed a cat (much to the horror of a large crowd of onlookers!).  Some years ago, an article in Herpetological Review recounted the story of a python that ate 2 chickens on a farm in China.  Upon capture, the snake regurgitated the chickens, which were promptly carted off by their rightful owner.  Domestic geese, ducks, goats, sheep, pigs and dogs are also taken on farms and in suburban areas.

Burmese Pythons in Florida are known to take endangered species such as Key Largo Wood Rats.  One now famous photo taken in the Everglades depicts a massive individual trying to swallow a large alligator.  In Puerto Rico, it is feared that introduced Burmese Pythons will out-compete and prey upon the endangered Puerto Rican Boa.

Please see my article Giant Snake Meals http://blogs.thatpetplace.com/thatreptileblog/2008/04/11/big-snake-meals/ for some personal and recorded observations on this topic (130 pound Impala, Siamese cat belonging to king of former Siam, etc.)

Status

Despite its wide range and adaptability, the Burmese Python is threatened in some regions by habitat loss and by over-collection for the leather and traditional medicine trades. Huge numbers were collected for sale as pets in years past, but most are now captive-born.

Burmese Pythons are bred in Vietnam for release as rodent control agents, but are killed for preying on domestic animals in other countries.  The species is listed on Appendix II of CITES and protected by the government ofIndia.

Longevity

Captives have lived for over 34 years; unknown in the wild.

Reproduction

Pythons possess a pair of vestigial legs (“spurs”) alongside the cloaca.  These are larger in males, and are rubbed along the female’s body during courtship.  Mating occurs from January through March, during periods of slightly reduced temperature.

In common with all pythons, the female protects and incubates her eggs.  Females engage in a “shivering” motion that can raise their own core temperatures and that of the egg clutch.

Female Burmese Pythons lay 18-100 eggs after a gestation period of 60-150 days.  The eggs hatch in 55-75 days.  The hatchlings are 18-24 inches long (large enough to consume adult mice) and become sexually mature at a length of approximately 10 feet (males) to 13 feet (females).  Under captive conditions, sexual maturity can be attained in 3 years.

 

 

Further Reading

Giant Snake Meals

Video: capture of huge python in Florida

The Giant Snakes (Clifford Pope, 1965); don’t miss this classic!

The Green Anaconda: Natural History of the World’s Largest Snake

Range information for all Pythons (40 species)

 

Burmese Python image referenced from wikipedia and originally posted by Mariluna
Albino Burmese Python image referenced from wikipedia and originally posted by Mike Murphy

The massive Reticulated Python, Broghammerus (formerly Python) reticulatus is one of the world’s best known snakes, and always the main attraction at zoo reptile houses.  It is also widely bred in private collections, although such is ill-advised given the potential dangers inherent in keeping such a formidable beast (even after decades in captivity, most retain their irascible temperament).  Today I’d like to explore a lesser known side of this impressive snake – its habits in nature, and its amazing ability to thrive even in large, crowded cities.

Description

The Reticulated Python, or “Retic” as it is known to herp enthusiasts, vies with the Green Anaconda for title of world’s longest snake  (an Anaconda would be twice as heavy as a Retic of the same length, however).  Stories abound as to its potential size, but the longest reliable measurement appears to be 32 feet, 9 inches; individuals longer than 23 feet are exceedingly rare. Read More »