Home | Field studies and notes (page 5)

Category Archives: Field studies and notes

Feed Subscription

Round Island Boa Reintroduction – Back in Wild after a 150-Year Absence

Casarea dussumieriMauritius, an island nation off the coast of southeast Africa, is best known to naturalists as the site of the Dodo Bird’s extinction (Mauritius also is, in a sense, the reason I was hired by the Bronx Zoo and spared life as a lawyer – see article below for the story!).  Herp enthusiasts, however, know it as the habitat of several unique reptiles, all of which are now very rare or extinct. But we can delight in some news just released by the Durrell Wildlife Trust – a new population of the Round Island or Keel-scaled Boas, Casarea dussumieri, will soon be established in the wild.  This unusual snake disappeared from nearly all of its range in the 1860’s, and its return is the culmination of 40 years’ worth of captive breeding and habitat restoration efforts.

Status and Conservation

The Round Island Boa is now confined to Round Island, a tiny speck of habitat where perhaps 500-1,000 individuals survive.  A single wild population and limited number of captives place it at continued risk of extinction.  The new population to be established on another Mauritian island (where the snake formerly lived) is a vital step towards ensuring the species’ survival.  Read More »

World’s Largest Snake – Finding and Keeping a Giant Reticulated Python

FluffyWhile working at the Bronx Zoo, I had the once-in-a lifetime opportunity of helping to import and care for one of the largest snakes in captivity.  While “largest snake” debates are ongoing, the massive Reticulated Python I came to know was awe-inspiring by any standard.  Dubbed “Samantha”, she was captured as an adult in Borneo, and eventually reached 26 feet in length and 275 pounds in weight.  The story of how she arrived in the USA involves a cash reward established by Theodore Roosevelt, the leather trade, animal dealers and other twists and turns.

Wanted: 30 Foot-Long-Snake

In 1910, Theodore Roosevelt, long involved with the Bronx Zoo, offered a reward to the first person who presented a snake of 30 feet in length; in time the reward grew to $50,000.  In 1992, I and other Bronx Zoo staff heard rumors that a giant Reticulated Python that had been captured in Borneo.  We did not get overly-excited… being well-seasoned, I automatically deducted 25-50% from the size of any “biggest snake-turtle-croc” stories that came my way.  But then grainy photos arrived by mail, and the snake depicted was, if not the largest I’d seen, impressive.  Whether by design or bad luck, the photos did not allow us to accurately gauge the animal’s length. Read More »

Amphibian Declines – Pollution Worsens Disease and Parasite Attacks

Deformed FrogIn 1990, the IUCN’s Declining Amphibian Populations Task Force, to which I belonged, was one of the few large scale efforts addressing what is now known as the “Disappearing Amphibian Crisis”.  Today, with legions of biologists and hobbyists at work on the problem, we still do not fully understand why nearly 200 species have become extinct in the last 20 years – a rate 200x that of what might be “expected”.  But we do have some insights, one of which was highlighted in a recent journal article (Philosophical Transactions of the Royal Society (Biology) .  It appears that stress, much of which is in response to what we are doing to amphibian habitats, is worsening the effects of normal pathogens and diseases.

Parasites and Insecticides: a Confusing Scenario

As the reality of worldwide amphibian declines became apparent, herpetologists and private citizens began noticing increasing numbers of deformed and dead frogs. In 1995, school children in Minnesota made headlines when they found dozens of deformed frogs in a local pond. Since several chemicals are known to cause growth abnormalities, researchers began focusing on pollutants. At the Bronx Zoo, I worked with a veterinarian who studied African Clawed Frogs, and was amazed to see ovaries develop in males that had been exposed to Atrazine (a common insecticide). Read More »

Boa Constrictors and their Relatives – Natural History and Captive Care

Malagasy tree boaThe 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 »

Green Anaconda Relatives – Bolivian, Dark-Spotted and Yellow Anacondas

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 »

Scroll To Top