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., S├ínchez, 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 |

Public Comment Sought on Plan to Restrict Giant Invasive Snakes

The U.S. Fish and Wildlife Service has published a proposed rule in the Federal Register to designate the Burmese python and eight other large constrictor snakes as “injurious wildlife” under the Lacey Act. If finalized, the designation will prohibit the importation and interstate transportation of these species.

In addition to the proposed rule, a draft economic analysis and environmental assessment are available for public review and comment for 60 days. These documents are available at: http://www.regulations.gov under Docket No. FWS-R9-FHC-2008-0015.

“We greatly value the public’s input and encourage engagement into this rulemaking process. The control of invasive species, including pythons and other large constrictor snakes, is a key step in our larger effort to restore the Everglades and protect other vulnerable areas of the country,” said Acting Service Director Rowan Gould.

On January 20, 2010, Secretary of the Interior Ken Salazar announced the Service would propose to designate these large constrictor snakes as injurious species. Salazar made the announcement at the Port of New York, which serves as the largest point of entry in the nation for imports of wildlife and wildlife products.

Under the Lacey Act, the Department of the Interior is authorized to regulate the importation and interstate transport of wildlife species determined to be injurious to humans, the interests of agriculture, horticulture or forestry, and the welfare and survival of wildlife resources of the United States.

The Burmese python (Indian python) is currently established across thousands of square miles in south Florida, and a population of boa constrictors is established south of Miami. In addition, evidence strongly suggests that a population of northern African pythons is reproducing on the western edges of Miami. The other species being considered in the proposed rule are the reticulated python, southern African python, yellow anaconda, DeSchauensee’s anaconda, green anaconda, and Beni anaconda. None of the nine species of snakes is native to the United States.

The U.S. Fish and Wildlife Service and National Park Service jointly funded a U.S. Geological Survey assessment, which highlighted the ecological risks associated with the establishment of the nine large constrictor species. All were shown to pose a high or medium risk to the health of ecosystems in the United States.

Burmese pythons and other large constrictor snakes are highly adaptable to new environments and prey on a wide variety and size of animals. Burmese pythons threaten many imperiled species and other wildlife. Two Burmese pythons were found near Crocodile Lake National Wildlife Refuge with the remains of three endangered Key Largo woodrats in their stomachs. As a result of these threats, more than 1,300 Burmese pythons have been removed from Everglades National Park and vicinity since 2000. Others have been removed from the Florida Keys, along Florida’s west coast and farther north along the Florida peninsula.

For Service information on injurious wildlife and how to send a comment, as well as links to partner agencies, visit: http://www.fws.gov/verobeach/index.cfm?method=activityhighlights&id=11

The mission of the U.S. Fish and Wildlife Service is working with others to conserve, protect and enhance fish, wildlife, plants and their habitats for the continuing benefit of the American people. We are both a leader and trusted partner in fish and wildlife conservation, known for our scientific excellence, stewardship of lands and natural resources, dedicated professionals and commitment to public service. For more information on our work and the people who make it happen, visit www.fws.gov.

Sunday, March 7, 2010

Gold Priced Out by Wildlife

Monday 1 March 2010, From the Zoological Society of London's Website.

18ft anacondas, jaguars, tapirs and the world’s largest bird of prey are some of the species that have proven to be worth more than their weight in gold.



Gold dredging has been outlawed in an unspoilt region of Guyana following a local campaign by concerned Amerindian villagers. This is being backed by scientists from the Zoological Society of London (ZSL).

The spotlight is being shone on this wildlife treasure trove by PhD students Rob Pickles and Niall McCann who travelled to the Rewa Head in Guyana to study giant otters and tapirs.

“During our brief survey we had encounters with wildlife that tropical biologists can spend years in the field waiting for. On a single day we had two tapirs paddle alongside our boat, we were swooped on by a crested eagle and then later charged by a group of giant otters. I think that about sums the place up. There is little human disturbance in the Rewa Head and as a result, wildlife flourishes in blissful naivety,” says Rob Pickles.

Rob and Niall carried out an extensive assessment of all wildlife in the area, recording 251 bird species and 33 large mammal species. They had close encounters with the largest species of snake, spider, eagle, armadillo and anteater, leading them to dub the area the ‘Land of the Giants’.

Following the success of banning gold dredging in the Rewa Head, Rob and Niall are working with ZSL conservationists to call for international support for the Guyanan government’s plan to turn its forests into the world’s largest carbon sink. The rich forests of Guyana present the perfect test case for implementing greenhouse gas reduction projects, such as REDD+ initiatives.

“The Rewa Head currently lies in a logging concession. Unless Guyana is given alternative financial incentives, its government will be forced to lease its land to oil drillers, miners and loggers. One of the world’s last Edens is on the brink of destruction,” says Niall McCann.

“In the wake of Copenhagen and the build up to the Convention on Biological Diversity, reducing biodiversity loss and greenhouse gas emissions are high on the political agenda. Protecting areas such as the Rewa Head through sustainable management is a positive strategy for addressing these key issues,” says Professor Jonathan Baillie, Director of Conservation at ZSL.

He adds: “Global leaders need to recognise that real economic benefits are to be gained through the conservation, not destruction, of our world’s living things.”

Thursday, March 4, 2010

Digestion vs Movement in Burmese Pythons

Boas and pythons can survive long periods without food. Literature reports pythons fasting for as long as 36 months. Work done by Stephen Secor and colleagues have demonstrated that python stomachs that have not been used for awhile  produce enough hydrochloric acid to change the pH from 7 to 1.5 in 48 hours, and the snakes maintain that pH for as long as six days while the meal is digesting. The pancreas is able to double its mass so that it can increase its enzyme production 6-20 times. The small intestine also doubles its mass, increases its enzyme production, and its ability to absorb nutrients.  that have eaten a large meal up-regulate the performance of their digestive systems. Now Secor and White have examined the blood flow of snakes after they have eaten a large meal and investigated what the snake does when it has to move while it is digesting food. They asked the question does the moving snake, carrying a gut full of food, alter its blood flow?  They used perivascular blood flow probes to measure blood flow in the several major arteries and veins. Snakes that were fasting and crawling increased their heart rate 2.7 times, and their cardiac output 3.3 times. A snake digesting a rodent that was about 25% of the snake's body weight increased its heart rate 3.3 times and its cardiac output 4.4 times. A crawling snake reduced its blood flow to to the digestive systems by 81%. Thus, Burmese pythons prioritize their blood flow, sending more blood to their muscles and less blood to the digestive system when they have to digest food and move at the same time. This has obvious survival value for the snake.

S. M. Secor and S. E. White. 2010.Prioritizing blood flow: cardiovascular performance in response to the competing demands of locomotion and digestion for the Burmese python, Python molurus. Journal of Experimental Biology 213: 78-88.

Tuesday, March 2, 2010

Sanajeh indicus, The Snake That Ate Dinosaurs

The remains of an extraordinary fossil unearthed in 67-million-year-old sediments from Gujarat, western India provide a rare glimpse at an unusual feeding behavior in ancient snakes.



Above: This is a life-sized reconstruction of the moment just before preservation. The scales and patterning of Sanajeh's skin is based on modern relatives of the fossil snake. The hatchling dinosaur is reconstructed from known skeletal materials, but its color is conjectural. The eggs are based directly on the fossils. (Credit: Sculpture by Tyler Keillor and original photography by Ximena Erickson; image modified by Bonnie Miljour)

An international paleontological team led by the University of Michigan's Jeff Wilson and the Geological Survey of India's Dhananjay Mohabey will publish their discovery online March 2 in the open-access journal PLoS Biology.

The remains of a nearly complete snake were found preserved in the nest of a sauropod dinosaur, adults of which are the largest animals known to have walked the earth. The snake was coiled around a recently hatched egg adjacent to a hatchling sauropod. Remains of other snake individuals associated with egg clutches at the same site indicate that the newly described snake made its living feeding on young dinosaurs.

"It was such a thrill to discover such a portentous moment frozen in time," said Mohabey, who made the initial discovery in the early 1980s.

Working with the sediment-covered and inscrutable specimen in 1987, Mohabey recognized dinosaur eggshell and limb bones but was unable to fully interpret the specimen. In 2001, Wilson visited Mohabey at his office at the Geological Survey of India and was astonished when he examined the specimen.

"I saw the characteristic vertebral locking mechanism of snakes alongside dinosaur eggshell and larger bones, and I knew it was an extraordinary specimen---but I also knew we needed to develop it further," Wilson said.

From that point began a decade-long odyssey that led to a formal agreement with the Government of India Ministry of Mines in 2004 that allowed preparation and study of the fossil at the U-M Museum of Paleontology, weeks of museum study in India, and field reconnaissance at the original locality in Gujarat by a team that included Wilson, Mohabey, snake expert Jason Head of the University of Toronto-Mississaugua, and geologist Shanan Peters of the University of Wisconsin. The field research was funded by the National Geographic Society.

Preparation of the fossil at the U-M revealed the snake was coiled around a crushed dinosaur egg next to a freshly hatched sauropod dinosaur.

"We think that the hatchling had just exited its egg, and that activity attracted the snake," said Mohabey. "The eggs were lain in the loose sands near a small drainage and covered by a thin layer of sediment."

The arrangement of the bones and delicate structures, such as eggshells and the snake's skull, point to quick entombment.

"Sedimentation was unusually rapid and deep for this formation---a pulse of sand, probably mobilized during a storm, resulted in the preservation of this spectacular association," said Peters, who interpreted the paleoenvironment of the site.

The new snake, which was named Sanajeh indicus or "ancient-gaped one from the Indian subcontinent," because of its lizard-like gape, adds critical information that helps resolve the early diversification of snakes. Modern large-mouthed snakes are able to eat large prey because they have mobile skulls and wide gapes. Sanajeh bears only some of the traits of modern large-mouthed snakes and provides insight into how they evolved.

"Sanajeh was capable of ingesting the half meter-long sauropod hatchling because it was quite large itself, almost 3.5 meters long," Head said. "This points to an interesting evolutionary strategy for primitive snakes to eat large prey by increasing their body size."

Although the sauropod dinosaurs that Sanajeh preyed upon include the largest animals capable of walking on land, they began their life as small hatchlings that were about one-seventh the length of Sanajeh. Sauropods appear to have achieved their enormous size by virtue of a fast-growth phase, which would have kept them out of danger from Sanajeh-sized predators by the end of their first year of life.

This discovery of Sanajeh adds to a growing body of evidence suggesting that the Indian subcontinent retained ties to southern landmasses for longer than once hypothesized. Sanajeh's closest relatives are from Australia and speak to its strong ties to southern continents, collectively known as Gondwana.

A life-sized flesh reconstruction of the scene immediately before burial was designed and executed by University of Chicago paleoartist Tyler Keillor. The team will donate the first cast to the Geological Survey of India at a formal function to be held in Mumbai, India, on March 12, 2010.

The full article can be found at:

http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.1000322

Friday, February 26, 2010

Thoughts on Cold Weather and Invasive Snakes.

The cold weather experienced in southern Florida has damaged crops causing economic damage to orange growers. It has also been proposed that the cold weather would solve the python problem. A January 1, 2010 Miami Herald article by Robert Samuels states,
"Scientists have waited for years for this moment. They are hoping that the extended, freakishly bitter cold just might accomplish what trappers have been unable to do: thin the population of pythons and other invaders running roughshod over the fragile environment and native species. Or at least slow their explosive growth."

The same article quotes University Florida Wildlife scientist Frank Mazzotti saying,  "Today has been what I would consider a game changer...The pythons are going to be stunned by this kind of weather."

Other articles report 50% of the Burmese Python found were dead, describe the invasive Green Iguana as falling out of trees, and state that many invasive freshwater fish have died.

The cold snap undoubtedly brought about a die-off of individual animals that were exposed to the cold but some individuals will have been in shelters where they would be protected from the cold. They may have learned how to survive the cold weather. But, some of them, maybe just a few, have a physiology that allows them to better withstand the cold. These snakes will survive, reproduce, and leave offspring that are also able to survive cold snaps. Overtime the populations of invasive constricting snakes will adapt to the local climate that includes the occasional cold front that sags into southern Florida. Just as bacteria become resistant to antibiotics, snake populations will become resistant to cold. If the Burmese Python, African Python, Boa Constrictor populations are large enough they too will likely become cold resistant.  Natural selection works this way. It should not be a surprise to any biologist.