Showing posts with label Crotalus adamanteus. Show all posts
Showing posts with label Crotalus adamanteus. Show all posts

Thursday, December 1, 2011

The Center for Biological Diversity Calls on Georgia to End Rattlesnake Round-Ups

Georgia Officials Called on to End Cruel, Dangerous Rattlesnake Roundups


ATLANTA— The Center for Biological Diversity and allies today sent a letter to Georgia wildlife officials urging them to enforce laws that protect both animals and people at “rattlesnake roundups” — annual contests in which hunters bring in as many snakes as they can catch in a year to be milked for venom, butchered, then sold for meat and skin. Two roundups take place every year in Georgia — one in Whigham in January, the other in Claxton in March. The letter was sent to local law-enforcement officials, the Georgia Department of Natural Resources, and roundup sponsors.

Georgia state law requires that anyone who possesses a wild rattlesnake obtain a “wild animal license” from the Department of Natural Resources. For the sake of both animal welfare and public safety, the law requires those who keep wild rattlesnakes to buy liability insurance and treat the snakes humanely. The groups’ letter, sent by the Center, Coastal Plains Institute and Land Conservancy, and One More Generation, asks that appropriate law-enforcement measures be taken before and during the roundups to make sure sponsors and participants carry insurance and give the snakes humane treatment.

“Possession of wild rattlesnakes without a license is against the law in Georgia for good, common-sense reasons, and the state needs to make the law real by enforcing it,” said Collette Adkins Giese, an attorney at the Center for Biological Diversity who works to protect rare and vanishing reptiles and amphibians. “But the best way to stop the abuse of animals, make sure no one gets hurt, and save the eastern diamondback from extinction is to just cancel these roundups. The bottom line is, they’re cruel.”

Rattlesnake roundups are depleting populations of eastern diamondback rattlesnakes: Analysis of data from four roundups in the southeastern United States shows a steady decline in the weights of prize-winning eastern diamondbacks and the number collected. This once-common species is being pushed toward extinction not only by hunting pressure but also by habitat loss and road mortality. In August, the Center and allies filed a petition to protect the snake under the Endangered Species Act.

“Georgia is blessed with a rich natural heritage of animals and plants. All of these species — even the rattlesnakes — should be allowed to exist and play their intended roles in our wild places,” said Adkins Giese. “It’s time to replace rattlesnake roundups with festivals that celebrate wildlife and educate folks on the importance of saving native species.”

In response to dwindling rattlesnake populations and public pressure, the town of Fitzgerald, Ga., has replaced its rattlesnake roundup with a wild chicken festival, which organizers report has been an enormous success.

For a link to photos of eastern diamondback rattlesnakes, please see: http://www.biologicaldiversity.org/species/reptiles/eastern_diamondback_rattlesnake/photos.html.

Tuesday, October 25, 2011

An Real Case of Sperm Storage in Eastern Diamondbacks

The New Scientist is carrying the following story. It is of interest because female snakes that have not been in contact with a male have produced offspring by parthenogenesis. Here is an apparent case of long term sperm storage. In most vertebrates sperm is thought to have a relatively short shelf life - unless of course the cells are placed in stasis, which some times happens in special sperm storage tubules.

FAMILY planning campaigners looking for a mascot should consider the eastern diamond-backed rattlesnake. A female of the species can store sperm in her body for at least five years before using it.

The rattlesnake (Crotalus adamanteus) in question was collected in Florida in 2005 and kept in a private collection for five years, with no contact with other snakes. In late 2010, she unexpectedly gave birth to 19 snakelets. To find out what had happened, Warren Booth of North Carolina State University in Raleigh took samples of DNA from the mother and her young.

Booth studies "virgin birth", in which a female produces young without any contribution from a male. But in this case the snakelets carried genes that their mother didn't, so she must have mated before she was captured and stored the sperm (Biological Journal of the Linnean Society, DOI: 10.1111/j.1095-8312.2011.01782.x).

Previous studies have hinted that reptiles can store sperm for several years, but this is the first case confirmed by genetics. Booth suspects other reptiles can store sperm even longer. "How long is anyone's guess," he says.It's becoming clear that snakes have unconventional ways of reproducing, including virgin birth and long-term sperm storage, says William Holt of the Institute of Zoology in London, though so far no one knows how they do it.

So much for the press release. In fact sperm storage in squamates has been relatively well studied. 


Oviducal sperm storage is known in females of all taxa of squamates except Amphisbaenia. However, in Rhynchocephalia and Crocodilia, sperm storage is poorly studied, and specialized sperm storage tubules (Ssts) are unknown. Sever and Hamlett (2002) used the molecular phylogenetic hypothesis [(Chelonia+Archosauria) (Squamata)] to trace evolution of sperm storage characters and found Ssts arose independently in Chelonia and Squamata. Turtles have albumen-secreting glands in the anterior half of the oviduct (the tuba or isthmus), and the most distal of these glands act as  Ssts; in addition, some turtles possess Ssts in the adjacent segment of the oviduct, the uterus. Squamates lack albumen-secreting glands, and the ancestral state is possession of Ssts in the posterior infundibulum (uterine tube). Secondarily, iguanids have evolved vaginal Ssts. They used ultrastructural observations on vaginal Ssts in lizards, with Anolis sagrei (Polychrotidae). Proximally, the neck of these simple tubular glands continues the alternation of ciliated and secretory cells lining the lumen of the vagina. However, the epithelial cells of the distal sperm storage area are neither secretory nor ciliated. The Ssts of Anolis are more similar to those of birds more than to infundibular receptacles in snakes and lizards.

Citation
Sever, D. M. and Hamlett, W. C. (2002), Female sperm storage in reptiles. Journal of Experimental Zoology, 292:187–199. doi: 10.1002/jez.1154