Monthly Archives: January 2013

CSC-Snakes of the United States mission, Project Noah weekly report

This week at Project Noah, I am pleased to report that the Snakes of the United States – Center for Snake Conservation (CSC) mission has had an addition of 12 new spottings bringing the total number of snake spottings to 1,276. I am also pleased to report we added 13 new members to the mission, bringing the total to 548 users.

The Project Noah: CSC-Snakes of the United States Mission Spotting of the week is this spectacular series of 2 male cottonmouths in combat! Many snakes have this type of combat when multiple males are vieing for the right to breed with a nearby female. It is much like arm wrestling in humans. Each snake tries to gain the upper hand and wrestle the other snake to the ground.
http://www.projectnoah.org/spottings/15238130

Please consider becoming a Project Noah member (it is free) and help make the world a better and safer place by educating the world about snakes! (We do make provisions for sensitive species asking that you merely record the nearest large town/community. Our goal is conservation through education.

Project Noah is an award-winning software platform designed to help people reconnect with the natural world. Launched out of NYU’s Interactive Telecommunications Program in early 2010, the project began as an experiment to mobilize citizen scientists and build a digital butterfly net for the 21st century. Backed by National Geographic, Project Noah is mobilizing a new generation of nature explorers and helping people from around the world appreciate their local wildlife. Our community is harnessing the power and popularity of new mobile technologies to collect important ecological data and help preserve global biodiversity. We currently have over 370,000 photos!

Our ultimate goal is to build the go-to platform for documenting all the world’s organisms, and through doing this we hope to develop an effective way to measure Mother Nature’s pulse. By developing tools to help the mobile masses share their encounters with nature, we are building a powerful force for crowdsourcing ecological data collection and an important educational tool for wildlife awareness and preservation. We hope you’ll support us on this mission by joining Project Noah today.

The Center for Snake Conservation needs your help to collect distributional data for all wild snakes in the United States. Please record all snakes including any snakes found dead on a road or elsewhere. Please include additional information about your spotting that can help us understand a bit more about the snake. As we collect spottings, we can increase our knowledge about snakes and help educate others that view our photos. Snakes are often unnecessarily feared and we can help change the human perception through our postings on Project Noah. http://www.projecthoah.org

http://www.snakeconservation.org/

Thanks, Lisa Powers

Project Noah – CSC Coordinator

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The snakes that eat caviar – Andrew Durso

This Blog was originally posted in Andrew Durso’s “Life is short, but snakes are long” blog on Tuesday, May 22, 2012

The snakes that eat caviar

Banded sea krait, Laticauda colubrina
Marine snakes are fascinating. Entire articles have been written about their morphological and physiological adaptations to marine life, from their lingual salt glands, which are more efficient than kidneys at removing sodium ions from their body, to their rudimentary left lung, which serves a function for the first time in millions of years, aiding in buoyancy control in a manner analogous to the swim bladders of many fishes. There appear to have been three separate invasions of the ocean by terrestrial snakes, all from the family Elapidae, which also includes cobras, mambas, and coral snakes. Although they have spread to east Africa and the south Pacific, all of these invasions have taken place in the shallow seas around Australia and southeast Asia. This is the center of elapid species diversity, so it’s no surprise that the greatest ecological diversity is also found here. Among the nearly 70 species of sea snake, however, two genera in particular stand out.
Most marine snakes eat eels and other tropical shore fishes, in accordance with their ancestors’ diets of large, bulky prey items that required venom or constriction to subdue. But in 1966, Harold Voris reported that the stomachs of two species of sea snake in the genus Emydocephalus, the turtle-headed sea snakes, were found to contain only fish eggs. This was a remarkable discovery, because most snakes eat prey that are relatively large compared to themselves, and they do so infrequently. It’s perhaps one of the evolutionary novelties that has allowed snakes to be so successful. But Emydocephalus eats tiny eggs, and it does so several times an hour, using a foraging mode similar to herbivorous browsing mammals, and to the lizard ancestors of snakes, than to other snakes. Turtle-headed sea snakes use chemoreception to locate the eggs, and the parent fishes are sometimes able to chase them away, despite being far smaller. The parent fishes are never eaten, and indeed they have little to fear, except for their fitness. Why?
There’s a reason there was no turtle-headed sea snake character in Finding Nemo
Voris also noticed that the dentition of these snakes was highly unusual, in that they almost completely lack teeth. Most snakes have teeth on up to five of their skull bones on each side: the maxilla, premaxilla, palatine, pterygoid, and dentary. Three of these bones (maxilla, premaxilla, and dentary) also bear teeth in humans and other mammals – the first two in your upper jaw, and the dentary (also called the mandible) in the lower. The palatine and pterygoid teeth of snakes are located on the bones that form the roof of your mouth, and they form what is essentially a second set of upper jaws inside of the first, which can move independently of the outer upper jaws and of each other. In Emydocephalus, only the pterygoid bone has any teeth, except for a single large proteroglyphous fang on each maxilla.
Partial skull of three species of sea snake, looking at the roof of the mouth from below. Figure modified from McCarthy 1987
It’s clear that a snake that ate only soft fish eggs wouldn’t need those teeth, but Voris couldn’t figure out how Emydocephalus actually ate fish eggs. He did notice that their stomachs also contained a good bit of sand, and occasionally a copepod (a type of crustacean). In 1987, Colin McCarthy proposed a mechanism that is very similar to that used by most fishes: suction. Based on his observations of the throat musculature of a closely related sea snake, Aipysurus eydouxi, also known to eat fish eggs, he suggested that the two genera of egg-eating sea snakes could create suction by contraction of the geniomucosalis muscle, which originates on the lower jaw and inserts on the oral mucosa (the lining of the mouth). The same mechanism is used by blindsnakes (Scolecophidia), the taxon in which the muscle was described only eight years earlier, to create suction as they feed on ant and termite pupae and larvae.
Graph showing the number of true sea snakes that feed on a variety of prey shapes From Voris and Voris, 1983
Other modifications of the head aid Emydocephalus and Aipysurus in finding and consuming fish eggs. Most snakes have six to eight labial scales (scales along the lip), whereas Emydocephalus has only three, giving it the appearance of a beak similar to that of a turtle (its genus name means ‘turtle-headed’ in Greek). McCarthy thought this helped keep the lips rigid during suction feeding. A spine at the tip of the rostral scale might aid in probing the sand for fish eggs buried there, but a secondary sexual function is also likely, because only adult male Emydocephalus have it.
Male Emydocephalus annulatus
In 1996, Michael Guinea published some of the first behavioral observations of wild Emydocephalus from northwestern Australia. While snorkeling, he watched as many as twenty individual E. annulatus interact on a circular coral mass only 25 feet in diameter. Algae grew on them, they moved so little. Mating males touched females with their spines, which might help them synchronize hourly trips to the surface for air and keep track of the female’s location as the pair return to the bottom, where Guinea observed pairs mating for over an hour. He also observed E. annulatus using their enlarged labial scales to scrape damselfish eggs off coral, but did not notice any evidence of suction feeding. He suggested that the geniomucosalis muscle was  instead used in rapid exhalation at the surface, and noted that exhalations of Emydocephalus can be heard, whereas those of other sea snakes lacking a geniomucosalis cannot (unlike Emydocephalus, other sea snakes exhale on their way to the surface, leaving a trail of bubbles).
Emydocephalus annulatus courting
You might have immediately associated sea snakes with potent venom, and you’re right to do so. It has been suggested that these marine snakes evolved simple, especially fast-acting venoms to immobilize their fish prey, which can escape in three dimensions rather than just two. However, Min Li and colleagues examined the venom of Aipysurus eydouxii and found a mutation that caused a 50- to 100-fold decrease in venom neurotoxicity. They also noted that A. eydouxii has greatly atrophied venom glands and relatively ineffective fangs. In their words, “It is interesting to note that a potent venom was not maintained for use in defense, thus reinforcing that the primary use of snake venom is for prey capture.” This is the first case of decelerated
evolution of toxins in snake venom, which is usually evolving rapidly, in an “arms race” with the immune system of the prey. Emydocephalus also have reduced fangs and venom glands, but no study of the chemical properties of their venom has been undertaken.
Aipysurus eydouxii
Are there any freshwater snakes that have similar adaptations to  Emydocephalus and Aipysurus? There are plenty that fill similar ecological roles to other sea snakes, eating fishes and crustaceans. There are lots of fishes and amphibians that lay tasty eggs in fresh water, but no freshwater snakes are known to have anything close to the morphological adaptations for oophagy of  Emydocephalus and Aipysurus. There are some terrestrial snakes that eat eggs, such as the neotropical Leptoderia, the African Dasypeltis, and the Australian Brachyurophis, the latter two of which  have lost many of their teeth and are incapable of eating other prey.
Leptodeira annulata eating Agalychnis callidryas eggs
ACKNOWLEDGMENTS
Thanks to the Field Museum archive for many of these images, and to Klaus Stiefel and il_mare77.
REFERENCES
Guinea ML (1996) Functions of the cephalic scales of the sea snake Emydocephalus annulatus. Journal of Herpetology 30:126-128
Li M, Fry B, Kini RM (2005) Eggs-only diet: its implications for the toxin profile changes and ecology of the marbled sea snake (Aipysurus eydouxii). Journal of Molecular Evolution 60:81-89 <link>
Li M, Fry BG, Kini RM (2005) Putting the brakes on snake venom evolution: the unique molecular evolutionary patterns of Aipysurus eydouxii (Marbled sea snake) phospholipase A2 toxins. Molecular Biology and Evolution 22:934-941
McCarthy C (1987) Adaptations of sea snakes that eat fish eggs; with a note on the throat musculature of Aipysurus eydouxi (Gray, 1849). Journal of Natural History 21:1119-1128
Shine R, Bonnet X, Elphick M, Barrott E (2004) A novel foraging mode in snakes: browsing by the sea snake Emydocephalus annulatus (Serpentes, Hydrophiidae). Functional Ecology 18:16-24 <link>
Voris HK (1966) Fish eggs as the apparent sole food item for a genus of sea snake, Emydocephalus (Krefft). Ecology 47:152-154 <link>
Voris HK, Voris HH (1983) Feeding strategies in marine snakes: an analysis of evolutionary, morphological, behavioral and ecological relationships. American Zoologist 23:411-425

Snakes of the United States Project Noah Mission – January 11, 2013 Update

This week at Project Noah, I am pleased to report that the Snakes of the United States – Center for Snake Conservation (CSC) mission has had an addition of 12 new spottings bringing the total number of snake spottings to 1,259. I am also pleased to report we added 9 new members to the mission, bringing the total to 535 users.
Please consider becoming a Project Noah member (it is free) and help make the world a better and safer place by educating the world about snakes! (We do make provisions for sensitive species asking that you merely record the nearest large town/community. Out goal is to conserve through education.
The Center for Snake Conservation needs your help to collect distributional data for all wild snakes in the United States. Please record all snakes including any snakes found dead on a road or elsewhere. Please include additional information about your spotting that can help us understand a bit more about the snake. As we collect spottings, we can increase our knowledge about snakes and help educate others that view our photos. Snakes are often unnecessarily feared and we can help change the human perception through our postings on Project Noah.www.projecthoah.org
Project Noah Snake Spotting of the Week
 
Florida Brownsnake – Storeria victa by Janson Jones
Many people would see a snake this size and automatically conclude that it is a baby snake. The fact is that many of our U.S. snakes get no bigger around than a number 2 pencil and may only reach a length of around a foot or less as adults. They are often secretive and spend much of the time underground, beneathe decaying logs/root balls or in leafy debris. The Florida brownsnake feeds on slugs, snails, and earthworms, but occasionally eats small fishes, frogs, and salamanders.
Last week at Project Noah, I am pleased to report that the Snakes of the United States – Center for Snake Conservation (CSC) mission has had an addition of 17 new spottings bringing the total number of snake spottings to 1,247. I am also pleased to report we added 16 new members to the mission, bringing the total to 526 users.
 
If you are a Project Noah member and wish to help us improve the database by recruiting new members and spottings to the CSC mission, please email Lisa Powers: froghavenfarm@hotmail.com
Project Noah Snake Spotting of the Week
 
Western diamond-backed rattlesnake (Crotalus atrox). The color pattern generally consists of a dusty looking gray-brown ground color, but it may also be pinkish brown, brick red, yellowish, pinkish or chalky white. This ground color is overlaid dorsally with a series of 24-25 dorsal body blotches that are dark gray-brown to brown in color. Adults commonly grow to 120 cm (3.9 ft) in length, specimens over 150 cm (4.9 ft) are more rarely encountered. Western diamond-backed rattlesnakes are found in the United States from central Arkansas and southeastern California, south into Mexico. Life expectancy is more than 20 years, but is typically shorter because of hunting and human expansion. They are also heavily collected from the wild, frequently being drawn out of their hiding places with gasoline, and used in Rattlesnake Round-Ups where they are killed for entertainment

 

Lisa Powers
Froghaven Farm
www.froghavenfarm.com

Tell me and I forget; Show me and I remember; Involve me and I understand.