Friday, July 23, 2010

Two Notes on the Reproduction of P. molurus

Two articles published in Reptile Rap, The Newsletter of the South Asian Reptile Network,  No. 10, June 2010 describe aspects of Python molurus reproduction.

Ramesh, C. and S. Bhupathy. 2010. A report on the unusual body weight of a hatchling Python molurus molurus. Reptile Rap (10):22-23.

This article describes a mean body weight of 111.2 g for a clutch of eggs laid in Keoladeo National National Park. However, one hatchling found dead near the nest weighed 200 g and showed no signs of deformity. Upon dissection the hatchling was found to have a mass of fat along the gut that may have disrupted normal body functions.

Balakrishnam, P. et al. 2010. Artificial incubation, hatching and release of the Indian Rock Python Python molurus (Linneaus, 1758), in Nilambur, Kerala. Reptile Rap (10):24-27.

Balakrishnam et al. used an environment chamber to incubate a batch of P. molurus eggs that were abandoned by the female due to human disturbance. The clutch of 17 eggs were kept between 28-32C and a relative humidity of 70-90%. Only one of the eggs hatched, the other eggs were opened and found to contain well developed embryos. The authors report that a large number of pythons are caught in lowland Nilambur and are translocated by the Forestry Department, a significant number of females snakes are killed and their eggs are left. A regional education program is in place to help protect snakes.

Wednesday, July 21, 2010

Florida Burmese Pythons are Regulating Egg Temperatures

The first report of a female Burmese Python using shivering thermogenesis in the wild has been described by Snow et al. (2010). The researchers placed data loggers in and around the brooding female python and found the female snake both warmed and cooled her eggs by generating body heat and cooling them through insulation.

Snow, R. W. et al. 2010. Thermoregulation by a brooding Burmese Python (Python molurus bivittaus) in Florida. Southeastern Naturalist 9(2):403-405.

Tuesday, June 8, 2010

Acetaminophen Toxic to Burmese Pythons and Nile Monitors

In the search to find a method to control large invasive reptiles Richard Mauldin and Peter Savarie of the United States Department of Agriculture tested acetaminophen as a potential poison to control the juveniles of alien Burmese Pythons and Nile Monitor Lizards. The pain killer was previously found to be toxic to Brown Treesnakes (Boiga irregularis) when it was administered orally. Does of 10, 20, and 40 mg resulted in mortality rates between 50 and 100%, while doses of 20, 40, and 80 mg resulted in mortality rates of 14.3, 85.7, and 100% respectively. The doses were administered by allowing the reptiles to swallow a dead neonatal mouse that contained a dose of acetaminophen. The implication is that feral reptiles could be attracted to bait that contained the toxin.

Citation: Mauldin, R. E. and P. J. Savarie. 2010. Acetaminophen as an oral toxicant for Nile monitor lizards (Varanus niloticus) and Burmese pythons (Python molurus bivittatus). Wildlife Research 37:215-222.

Saturday, June 5, 2010

Burmese Python Distribution in China Re-examined

Dave and Tracy Barker have published an updated summary of the distribution of bivittatus in China. They examine the distribution by province and analyze the known records for each. The most eastern record occurs at Naping in Fujian Province. It has also been recently reported from The Kimmen Archipelago on Queymoy Island. They found no records of the species in Guangxi, but note it is widely reported in the literature to be present. One record of a specimen from Jiangxi based on the literature appears to be based upon a visual sighting and a shed skin. P. bivittatus appears to be present in extreme southern Yunnan (on the Vietnam border) as well as extreme western Yunnan, avoiding the Shan Plateau. The authors consider the presence of bivittatus in Sichuan Province problematic. Both specimens were associated with urban areas and could represent human introduction.

Barker, D. G. and T. M. Barker. 2020. The distribution of the Burmese Python, Python bivittatus, in China. Bulletin of the Chicago Herpetological Society 45:86-88.

Saturday, May 29, 2010

Cold Weather and Florida Python bivitattus

Michael Avery and colleagues (2010) at the USDA Animal and Plant Health Inspection Service in Gainesville, Florida have produced a new report published in Biological Invasions online on 22 April. They housed three female and six male Burmese Pythons at their facility. The snakes were held in outdoor cages made of an aluminum frame with plastic coated wire. Each cage contained a hide box that contained a heat producing mat. When the outside temperature was 5.7 to 9ºC the heat mat was at 26.7ºC. During the January cold spell three of the nine snakes died, two others developed infections and were eventually euthanized and two others exhibited signs of respiratory distress but were treated for the infection. Thus, seven of the nine snakes died or would have died without human intervention during the cold spell. The authors concluded that cold weather may well be a limiting factor in the dispersal of the snakes out of Florida.

Avery, M. L. et al. 2010. Cold weather and the potential range of invasive Burmese Pythons. Biological Invasions doi 10.1007/s10530-010-9761-4

Thursday, April 29, 2010

Viruses in Captive Boids and Pythonids

A recently published study from Germany examined 100 apparently healthy booid snakes for the presence of paramyxoviruses (PMVs), and tested blood samples for antibodies against PMVs, adenoviruses and reovirus and for inclusion bodies that would indicate the presence of inclusion body disease (IBD). Nine snakes tested positive for PMVs and six snakes tested positive for IBD antibodies. Antibodies against PMV were found in one snake and two snakes had antibodies against an adenovirus.The blood samples were obtained from 14 private and zoo collections in Germany and taken only from snakes that showed no signs of disease. Snake owners answered detailed questionnaires about the snakes origins, diet, and husbandry. The authors suggest that the risk of spreading an infection in a collection is considerably greater that previously thought from snakes that appear healthy. The full article can be found at: http://www.veterinaer-akademie.de/pdf/en/publications/2010_veterinary_record_03_snakes.pdf

Citation: Pees, M. et al. 2010. Prevalence of viral infections in captive collections of boid snakes in Germany. Veterinary Record 166:422-425.

Bill to Ban Sale of Giant Snakes To Be Signed By Florida Governor

The Miami Herald is reporting this morning (4/29/2010) that the Florida State Legislature is getting ready to ban the sale of Burmese Pythons, African Pythons, and Anacondas as well as Nile Monitor Lizards that have become invasive species. Of course this will do little to prevent the spread of the populations of these animals already established in the state. The bill was approved by the Legislature on Wednesday and is headed for the Governor's desk. The full article can be found at: http://www.miamiherald.com/2010/04/29/1603455/state-poised-to-ban-the-sale-of.html

Sunday, April 18, 2010

Python Hunting Season Has Ended in Florida

The Florida python hunting season that opened March 8 ended on April 17. No snakes were killed by hunters during the relatively short time period. Additionally, 9 of 10 snakes that were being tracked with implanted radio transmitters in Everglades National Park died and, the tenth was reported in poor condition. All of this follows an unseasonably cold January. Does this mean that 90 to 100% of the invasive pythons died? The answer to this is unknown. Snakes with implanted transmitters may have been more susceptible to the stress produced by the cold because of the surgery; they may have been more active than other snakes and closer to the surface or more exposed to the cold. Other unknown factors may have made them more sensitive to the cold weather. Officials who claimed the 50% of the snakes, snakes and other invasive reptiles died from the cold snap have no real way of supporting that number and it has generated considerable skepticism and sarcasm in the press considering that 90% of the snakes that were being tracked died. Ten snakes is a relatively small sample size, particularly in light of the size of the area occupied by the snakes. With the approach of summer I suspect python sightings are likely to increase and those that are seen are likely to be the ones that are cold resistant because of their physiology or behavior.

Monday, April 12, 2010

Human Fascination With Large Snakes is Ancient

There is evidence that humans have been moving the large snakes around for at least two millennia. Strabo’s encyclopedic work Geography is a description of the ancient Greco-Roman world. In this 2000 year old text the author reports seeing a snake in Egypt that was 9 cubits long (about 13 feet or about 4 m) that had been brought from India. The same appears true for the African Python complex (Python sebae). Bodson (2004) described, what she considers, the first herpetological expedition to capture a large African Python organized under Ptolemy II (290 to 246 BC). The expedition captured a large specimen in the area known as the Island of Meroe, which is not really an island but the area between the White Nile, the Blue Nile and the Atbara River (14-16°N latitude). This area is within the known range of Python sebae. There are no firsthand accounts of the 3rd century BC effort and Bodson's account is based on information in a ms from the 1st century BC, at least 200 years after the event. Therefore it is not surprising that the size and abilities of the snake were exaggerated. Accounts from the turn of the 19th century suggest people in the Philippines were using Reticulated Pythons (Broghammerus reticulatus) to control rodents, keeping them in their houses and places of business. This may have lead Brown and Acala (1970) to concluded that the presence of reticulatus on virtually all Philippine islands were the result of human transport. It is therefore not surprising that 15 foot Burmese Python (P. bivittatus) was found in Riverside, California's Lake Evan over the week end (April 9) and an 11 ft python of an unstated species was found in Cornwell, England on April 11. Of course people keep giant snakes as pets or for commercial breeding projects today. Human fascination with snakes is ancient and undeniable.

Friday, April 2, 2010

Large Male African Python Found in Dade County, Florida

The SunSentinel.com reported on March 20, 2010 that a 14 foot (4.27 m), 140 pound (63.5 kg) male African Rock Python had been captured in West Miami (Dade County) in January. The species (Python sebae) was first discovered living in Florida in September of 2009. The news report suggests this is an unusually large male. In southeast Nigeria Luiselli et al. (2007, pages 89-100 in Henderson and Powell, Biology of Boas and Pythons, Eagle Mountain Publishing) measured 51 female and 39 male African Pythons and found females averaged 4.15 m and males 2.47 m. The largest female observed was about 5 m. Thus, the male from Dade County appears to be exceptionally large compare with the African population studied, suggesting this species may be finding food to be nutritious and plentiful in Florida.

Reticulated Python Kills Boy in Indonesia -Predation

The Associated Press reports that a 13-year-old boy was killed by a python (Broghammerus reticulatus) on 21 March on Sumatra (Indonesia). The local police cheif, Capt. Joshua Tampubolon reported  a 23-foot (7-meter-long) python was believed to be hiding in waterway tunnels built by a textile company for its industrial waste. Villagers from Percut Sei Tuan in Deli Serdang district blocked road access to the tunnels Sunday to protect the public. The victim and three friends were swimming in the Tembung River when the snake attacked. It strangled and nearly swallowed the boy before villagers armed with spears forced it to flee. It is interesting to note that this attack was an attempt at predation on a human, and was not the result of an "accident" as often described when deaths occur from captive snakes.

Wednesday, March 31, 2010

African Pythons Partially Protected from Bushmeat Trade by Traditional Beliefs

Hunting bushmeat is West Africa has become more than subsistence, it has become a source of income for many people. In a survey of bushmeat hunting in Cameroon, Julie Wright and Nancy Priston of Oxford University found the species most preferred were porcupines, guenons, pangolins, cane rats, red duikers and other mammals and birds. However, some species were avoided by some hunters because of traditional beliefs. Chimps, gorillas, leopards, forest buffalo, forest elephants, and Python sebae were avoid by 83% of the hunters because of the belief that some people can transform themselves into animals. Hunters avoided these species for fear of killing a person.

Wright, J. H. and N. E. C. Priston. 2010. Hunting and trapping in Lebialem Division, Cameroon: bushmeat harvesting practices and human reliance. Endangered Species  Research 11:1-12. Open Access at: http://www.int-res.com/articles/esr2010/11/n011p001.pdf

Sunday, March 28, 2010

Anti-Inflammatory Molecule from the Blood Serum of the Reticulated Python

Antivenom is currently the only treatment for snake envenomation, antivenom tends to be species specific, is not available in many places, and is not effective for local tissue damage (necrosis) done by enzymes, nor is it effective at reversing some enzymatic neurotoxins (phospolipases A2s) that act presynaptically. PLA2s are enzymes found in virtually all snake venoms. PLA2 are molecules that are common in many organisms and have been slightly modified by snakes for use in venom. PLA2s have been implicated as playing a role in multiple diseases including rheumatoid and osteoarthritis, asthma, acute pancreatitis, and septic shock. There are also PLA2 inhibitor molecules (PLIs) in the blood serum of many animals including snakes. Maung-Maung Thwin of the National University of Singapore and colleagues have reviewed the information on PLIs. and purified a PLI from the serum of the Reticulated Python (Brogersmannus reticulatus) and produced a synthetic molecule which is the same as the naturally occurring one. The PLI from the python neutralizes a variety of snake venom and prevents swelling and contains a peptide that may be useful in combating inflammation as well as the damage done to local tissues by snake venom.

Citation: Thwin, M. M., R. P. Samy, S. D. Satyanarayanajois, and P. Gopalakrishnakome. 2010. Venom neutralization by purified bioactive molecules: synthetic peptide derivatives of the endogenous PLA2 inhibitory protein PIP (a min-review). Toxicon doi:10.1016/j.toxicon.2009.12.023

Tuesday, March 16, 2010

The Mechanism for Transducing Infra-Red in the Pits of Viperids, Boids and Pythonids

Edward Tyson was first to dissect a rattlesnake and provide a detailed description of the viper for the 17th century scientific community. His description included the loreal pits. His interpretation of the pits was ―they were ears. The true function of the pits was not discovered until the 1950’s when Theodore Bullock and F. P. J. Diecke experimentally demonstrated the loreal pits of pit-vipers and the labial pits of boids and pythonids were in fact heat sensors.

[caption id="attachment_144" align="aligncenter" width="650" caption="Heat sensing pits in a Mojave Rattlesnake, an Emerald Treeboa, and a Ball Python. Photos copyright John C. Murphy."][/caption]

Now, Elana O. Gracheva and colleagues at the University of California, San Francisco have revealed the mechanism used to transduce the infra-red heat into nerve impulses.  Using unbiased transcriptional profiling, the research team identified TRPA1 channels as the infra-red receptors on sensory nerve fibers. TRPA1 channels are the most heat sensitive ion channels known in vertebrates.

In humans, the TRPA1 orthologue is activated by allyl isothiocyanate, the molecule that gives wasabi and mustard their kick. And, in most vertebrates the TRPA1 molecule is associated with the detection of noxious chemicals, but in some invertebrates (such as fruit flies) it is known to detect heat, and it is used by vampire bats to detect heat.

Gracheva and colleagues tested TRPA1 orthologues in Western Diamondback Rattlesnakes (Crotalus atrox), Texas Rat Snakes (Pantherophis obsoleta lindheimeri), Western Coachwhips (Masticophis flagellum testaceus), Ball Pythons (Python regius), and Amazonian Treeboas (Crorallus hortulanus). The molecules were most active in the pits of the rattlesnake. The heat sensing molecules were obtained from the trigeminal nerve ganglia of each species.

Rattlesnake TRPA1 was found to be inactive at room temperatures, but it became robustly active at temperatures of about 28°C. The Rat Snake’s TRPA1 was also sensitive to heat, but did not become active until it reached 36°C, and of course, the Texas Rat Snake and Coachwhip lack specific organs to detect heat.

The boa and python tested showed TRPA1 heat sensitivity also, both had a higher threshold to heat, with the molecules becoming active at temperatures of about 30° and 33°C respectively. However, the constrictors’ labial pits were 5 to 10 times less sensitive to heat than were the pit vipers.

To be sure, pit vipers and the large constrictors evolved the heat sensing mechanisms independently of each other. Furthermore, the boids and pythonids are no longer known to be each other’s closest relatives. Thus, the question becomes did the labial pits of boas and pythons also evolve independently from each other, or were they present in some ancient common ancestor?

Citation:  Gracheva, E., Ingolia, N., Kelly, Y., Cordero-Morales, J., Hollopeter, G., Chesler, A., Sánchez, E., Perez, J., Weissman, J., & Julius, D. (2010). Molecular basis of infrared detection by snakes Nature DOI: 10.1038/nature08943

Friday, March 12, 2010

Ticks, Their Parasites, and Reptiles

A forthcoming article in the journal Veterinary Parasitology reports on invasive species of ticks (Acari: Ixodida) have been imported into Poland. The article was published first on-line on January 20, 2010 and the full reference is given below. Between 2003 and 2007 Magdalena Nowak of Pedagogical University of Cracow examined 382 specimens of reptiles imported into Poland from Ghana. Nowak found more than 2100 specimens of ticks in the genera Amblyomma and Hyalomma, and they represented 8 species of Amblyomma and one species of Hyalomma. Extracts of 345 ticks were examined for the presence of DNA from Anaplasma phagocytophilum (causes human granulocytic anaplasmosis) and Rickettsia spp. (causes spotted fever group or human rickettsiosis). The author confirmed the presence of Anaplasma phagocytophilum in two ticks of Amblyomma flavomaculatum (constituting 0.6% of all the ticks investigated) that had fed on the Savanna Monitor Lizard (Varanus exanthematicus). None of the tick specimens, however, contained Rickettsia spp. DNA. The import of exotic reptiles in Poland and Central Europe is important for parasitological and epidemiological reasons and Nowak suggests that it requires monitoring to prevent the spread of exotic parasites. Of course, its not just Poland that has this problem. Any country importing wild caught reptiles risks importing ticks and their parasites. The large, wild caught pythons and boas frequently harbor ticks and are therefore associated with this problem.

Nowak, M. 2010. The international trade in reptiles (Reptilia)—The cause of the transfer of exotic ticks (Acari: Ixodida) to Poland. Veterinary Parasitology. doi:10.1016/j.vetpar.2010.01.006 |