About Vipers, Family Viperidae

About Vipers, Family Viperidae Vipers (Viperidae) are a group of snakes known for their long fangs and venomous bite. Vipers include true vipers, bush vipers, rattlesnakes, pit vipers, adders and night adders. Venomous Fangs The fangs of vipers are long and hollow and enable the snake to inject venom into animals that it bites. Venom is produced by and stored in glands located at the back of the snakes upper jaw. When the snakes mouth is closed, the fangs recede into a thin membrane and fold against the roof of the snakes mouth. When a viper bites its victim, the bones of the jaw rotate and flex so that the mouth opens at a wide gape angle and the fangs unfold at the last moment. When the snake bites down, muscles that encase the venom glands contract, squeezing venom out through ducts in the fangs and into their prey. Types of Venom Several different types of venom are produced by the various species of vipers. Proteases consist of enzymes that break down proteins. These enzymes cause a variety of effects in bite victims including pain, swelling, bleeding, necrosis, and disruption of the clotting system. Elapid venoms contain neurotoxins. These substances disable prey by disabling muscle control and causing paralysis. Proteolytic venoms contain neurotoxins to immobilize prey as well as enzymes that break down molecules in the victims body. Head Shape Vipers have a triangular-shaped head. This shape accommodates the venom glands at the back of the jaw. Most vipers are slender to stout-bodied snakes with a short tail. Most species have eyes with elliptical pupils that can open wide or close down very narrowly. This enables the snakes to see in a wide range of light conditions. Some vipers have keeled scales- scales with a ridge in their center- while others have smooth scales. 26 Types There are currently about 26 species of vipers that are considered vulnerable, endangered or critically endangered. Some of the rarest vipers include the golden lancehead and the Mt. Bulgar viper. Like most snakes, vipers appear not to care for young after hatching. Most species of vipers give birth to live young but there are a few species that lay eggs. Vipers occur in terrestrial habitats throughout North, Central and South America as well as in Africa, Europe, and Asia. There are no vipers native to Madagascar or Australia. They prefer terrestrial and arboreal habitats. The range of vipers extends further north and further south than any other group of snakes. Vipers feed on a variety of small animal prey including small mammals and birds. Classification Vipers belong to the snake family. Snakes are among the most recently evolved of the main reptile lineages alive today. Their evolutionary history remains somewhat murky, though- their delicate skeletons do not preserve well and as a result, few fossil remains of ancient snakes have been recovered. The earliest known snake is Lapparentophis defense which is estimated to have lived about 130 million years ago, during the early Cretaceous. The viper family includes about 265 species. Vipers are classified into one of four groups: Azemiopinae: Feas viperCausinae: night addersCrotalinae: pit vipersViperinae: true vipers The Viperinae, also known as the Old World vipers, are short and stocky snakes. They have a wide, triangular head and rough, keeled scales. Their coloration is dull or cryptic providing them with good camouflage. Most members of this group give birth to live young. Pit vipers are distinct from other vipers due to a pair of heat-sensitive pits located on either side their face between the eyes and nostrils. Pit vipers include the worlds largest viper, the bushmaster, a snake native to Central and South American rainforests. The bushmaster can grow as long as 10 feet. Of all vipers, the rattlesnakes are among the most easily recognized. Rattlesnakes have a rattle-like structure at the end of their tail formed out of old layers of the terminal scale that do not fall off when the snake molts. When shaken, the rattle serves as a warning signal to other animals.

Sally Hemings Her Relationship With Thomas Jefferson

Sally Hemings Her Relationship With Thomas Jefferson An important note on terms: the term mistress refers to a woman who lived with and was sexually involved with a married man. It does not always imply that the woman did so voluntarily or was completely free to make the choice; women through the ages have been pressured or forced into being mistresses of powerful men. If it was true and examine the evidence outlined below that Sally Hemings had children by Thomas Jefferson, it is also undoubtedly true that she was enslaved by Jefferson (for all but a brief time in France) and that she had no legal ability to choose whether or not to have a sexual relationship with him. Thus, the often-used meaning of mistress in which the woman chooses to have a relationship with a married man would not apply. In the Richmond Recorder in 1802, James Thomson Callendar first began to publicly allege that Thomas Jefferson kept one of his slaves as his concubine and fathered children with her. The name of SALLY will walk down to posterity alongside Mr. Jeffersons own name, Callendar wrote in one of his articles on the scandal. Who Was Sally Hemings? What is known of Sally Hemings? She was a slave owned by Thomas Jefferson, inherited through his wife Martha Wayles Skelton Jefferson (October 19/30, 1748 - September 6, 1782) when her father died. Sallys mother Betsy or Betty was said to be the daughter of a black slave woman and a white ship captain; Betsys children were said to have been fathered by her owner, John Wayles, making Sally a half-sister of Jeffersons wife. From 1784, Sally apparently served as a maid and companion of Mary Jefferson, Jeffersons youngest daughter. In 1787, Jefferson, serving the new United States government as a diplomat in Paris, sent for his younger daughter to join him, and Sally was sent with Mary. After a brief stop in London to stay with John and Abigail Adams, Sally and Mary arrived in Paris. Why Do People Think Sally Hemings Was Jefferson's Mistress? Whether Sally (and Mary) lived at the Jefferson apartments or the convent school is uncertain. What is fairly certain is that Sally took French lessons and may also have trained as a laundress. What is certain is that in France, Sally was free according to French law. What is alleged, and not known except by implication, is that Thomas Jefferson and Sally Hemings began an intimate relationship in Paris, Sally returning to the United States pregnant, Jefferson promising to free any of her (their) children when they reached the age of 21. What little evidence there is of a child born to Sally after her return from France is mixed: some sources say the child died quite young (the Hemings family tradition). What is more certain is that Sally had six other children. Their birth dates are recorded in Jeffersons Farm Book or in letters he wrote. DNA tests in 1998, and a careful rendering of the birth dates and Jeffersons well-documented travels puts Jefferson at Monticello during a conception window for each of the children born to Sally. The very light skin and the resemblance of several of Sallys children to Thomas Jefferson were remarked upon by a good number of those who were present at Monticello. Other possible fathers were either eliminated by the 1998 DNA tests on male-line descendants (the Carr brothers) or dismissed because of internal inconsistencies in the evidence. For example, an overseer reported seeing a man (not Jefferson) coming from Sallys room regularly but the overseer did not start working at Monticello until five years after the time of those visits. Sally served, probably, as a chambermaid at Monticello, also doing light sewing. The affair was revealed publicly by James Callender after Jefferson refused him a job. There is no reason to believe she left Monticello until after Jeffersons death when she went to live with her son Eston. When Eston moved away, she spent her last two years living on her own. There is some evidence that he asked his daughter, Martha, to give Sally her time, an informal way to free a slave in Virginia which would prevent the imposition of the 1805 Virginia law requiring freed slaves to move out of the state. Sally Hemings is recorded in the 1833 census as a free woman. Bibliography Sally Hemings: Redefining History. A video from AE/Biography: Here is the complete story of the woman at the center of the first presidential sex scandal. (DVD or VHS)Jeffersons Secrets: Death and Desire in Monticello.  Andrew Burstein, 2005.  (compare prices)Thomas Jefferson and Sally Hemings: An American Controversy: Annette Gordon-Reed and Midori Takagi, reprint 1998.  (compare prices)Sally Hemings and Thomas Jefferson: History, Memory, and Civic Culture: Jan Lewis, Peter S. Onuf, and Jane E. Lewis, editors, 1999.  (compare prices)Thomas Jefferson: An Intimate History: Fawn M. Brodie, trade paperback, reprint 1998.A President in the Family: Thomas Jefferson, Sally Hemings, and Thomas Woodson: Byron W. Woodson, 2001.(compare prices)Sally Hemings: An American Scandal: The Struggle to Tell the Controversial True Story.  Tina Andrews, 2002.Anatomy of a Scandal: Thomas Jefferson and the Sally Story.  Ã‚  Rebecca L. McMurry, 2002.The Jefferson-Hemings Myth: An American Trave sty.  Ã‚  The Thomas Jefferson Heritage Society, Eyler Robert Coates Sr., 2001 The Jefferson Scandals: A Rebuttal.  Ã‚  Virginus Dabs, Reprint, 1991.Jeffersons Children: The Story of an American Family.  Shannon Lanier, Jane Feldman, 2000.   For young adults.Sally Hemings: Barbara Chase-Riboud, reprint 2000. Historical fiction.