askook

Tentacled snakes turn C-starts to their advantage and predict future prey behavior PNAS (2009) Vol.106, N°.27, p.11183-11187 Kenneth C. Catania http://www.pnas.org/content/early/2009/06/18/0905183106.full.pdf+html

Venomous Sea Snakes Play Heads Or Tails With Their Predators In a deadly game of heads or tails venomous sea snakes in the Pacific and Indian Oceans deceive their predators into believing they have two heads, claims research published August 5 in Marine Ecology. The discovery, made by Dr Arne Redsted Rasmussen and Dr Johan Elmberg, showed that Yellow-lipped Sea Kraits (Laticauda colubrina) use skin markings and behaviour patterns to fool predators into thinking their tail is a second head, complete with lethal venom. There are over 65 species of sea snakes in the tropical waters of the Southern Hemisphere, ranging from Africa to the Gulf of Panama. Most spend their entire lives in the sea, inhabiting shallow water and are active predators, feeding on small fish found around coral reefs. All sea snakes have extremely potent venom which is among the most toxic known in all snake species. When hunting for food sea snakes probe crevices and coral formations, temporarily forcing them to drop their guard to threats from the surrounding waters and making them highly vulnerable to attack. However, the Yellow-lipped Sea Krait has been found to twist its tail so that the tip corresponds with the dorsal view of the head, which combined with deceptive colouring, gives the illusion of having two heads and two loads of deadly venom. Apart from the Yellow-lipped Sea Krait the ecology of sea snakes has largely gone understudied, due mainly to their off-shore and nocturnal behaviour. Yet, despite the number of behavioural studies devoted to this species, the discovery of this false-head-behaviour is a hitherto overlooked anti-predator adaptation. The discovery was made while senior author Arne Redsted Rasmussen was diving off the coast of the Bunaken Island in Indonesia. A large Krait was followed for thirty minutes, swimming between corals and crevices hunting for food. Rasmussen was momentarily distracted by a second snake, but when looking back he was surprised to see the "head" was facing him while the tail probed the coral. Rasmussen's surprise grew when he saw a second head emerge from the coral instead of the expected tail. It was only when the snake swam away that the first head was clearly seen to be a paddling tail. To build upon this discovery researchers examined 98 Sea Kraits from three major museum collections in Paris, Berlin and Copenhagen while also monitoring the behaviour of wild Sea Kraits in Solomon Islands during the Danish Galathea 3 Expedition. The research confirmed that all snakes of this species had a distinctive colouration pattern, with a bright yellow horseshoe marking on the tip of the head and the tail. The yellow was deeper than the colours on the rest of the body and the black colorations were much longer than the dark bands on the rest of the body, highlighting the similarity between the head and the tail. The reason for this mixture of behaviour and coloration results from a developed defence strategy needed when the snake is probing for prey. Despite being extremely venomous sea snakes are susceptible to attack from several predators such as sharks, large bony fishes, and even birds. "The value of such an adaptation is twofold; it may increase the chances of surviving predator attack by exposing a less 'vital' body part, but more importantly it may deter attack in the first place if attackers perceive the tail as the venomous snakes head," said Rasmussen. Similar defence mechanisms have been discovered in lizards, and some land snakes have developed ingenious camouflage deterrent behaviour strategies, but this defence has never been associated with other lethally venomous predators such as sea snakes. Traditionally the only evidence of a defence behaviour strategy in sea snakes has been documented in individual cases, when a snake was exposed to and aware of an imminent danger. This research is the first record of a combined false-head-behaviour and false-head-camouflage defence strategy used as instinct when a snake is hunting for food. "It is intriguing that this discovery is observed in this species, as one of the key differences between the Yellow-lipped Sea Krait and other sea snakes is that they spend almost equal time on land and in the sea," said Rasmussen. "They therefore live in two worlds where two very different rules of survival apply. It remains to be confirmed whether Sea kraits use their sea defence tactic of motioning their tails when on land." Source:http://www.sciencedaily.com/releases/2009/08/090805201539.htm Traduction: http://translate.google.com/translate?hl=fr&u=http%3A%2F%2Fwww.sciencedaily.com%2Freleases%2F2009%2F08%2F090805201539.htm

‘Head for my tail’: a new hypothesis to explain how venomous sea snakes avoid becoming prey Marine Ecology (2009), p. 1-6 Arne Redsted Rasmussen & Johan Elmberg http://www3.interscience.wiley.com/cgi-bin/fulltext/122540095/PDFSTART

‘Head for my tail’: a new hypothesis to explain how venomous sea snakes avoid becoming prey

Une nouvelle campagne de pub lancée au Brésil encourage les gens à sauver l'eau en urinant plus souvent dans la douche. Le groupe brésilien environnemental SOS Mata Atlantica dit que cette pub, visible sur plusieurs chaînes, utilise l'humour pour persuader les gens de réduire leur consommation d'eau. Le groupe rappelle que si chaque ménage évite de tirer la chasse une seule fois par jour, 4.380 litres d'eau pourront être économisés chaque année. La porte-parole de SOS Mata Atlantica explique que c'est un sujet grave abordé d'une manière ludique. La pub montre, sous forme de petits cartoons, des personnages de différents horizons: un trapéziste, un joueur de basket, un alien, uriner dans leur douche. Elle se termine par une voix d'enfait qui dit: "Pissez dans la douche! Sauvez la forêt tropiquale atlantique."

C'est un accident plus que surprenant qui a eu lieu ce mardi sur une autoroute israélienne. Un cheval en fuite a foncé sur une voiture. La scène a été filmée par des touristes. Ils roulaient tranquillement sur l'autoroute quand ils ont aperçu trois chevaux en pleine course. Soudain, une voiture arrive en sens inverse. Si les deux premiers chevaux parviennent à éviter l'obstacle, le troisième, quant à lui, tente de sauter par dessus mais en vain. Après avoir écrasé la voiture de la famille, il a repris sa course abandonnant les occupants de l'auto complètement terrorisés. Par chance, le conducteur du véhicule n'a été que très légèrement blessé. Le cheval l'a lui aussi échappé belle et ne souffre que de quelques blessures superficielles.

House Judiciary Committee to Hear Python Ban Bill The House Judiciary Council will hold a hearing at 10 a.m. EDT on Wednesday July 29 on a bill that would ban trade in pythons. On Tuesday, the bill passed through a subcommittee markup session without any amendments, the Pet Industry Joint Advisory Council reported. At Wednesday's full committee markup session, Rep. Thomas Rooney (R-Fla.) is expected to offer an amendment that would limit the ban to Burmese and African rock pythons, PIJAC reported. As currently written, HR 2811, a companion bill to S. 373, would add “the constrictor snake of the species Python genera” to the Lacey Act as an injurious species that would be “prohibited from being shipped or imported into the United States.” However, PIJAC warned the bill would have broader consequences, as the Lacey Act also prohibits exports and interstate movement of listed species. Moreover, the legislation as written would cover all species of python, including the common pet ball pythons, rather than just the Burmese python that is of concern in Florida. PIJAC on Tuesday afternoon encouraged concerned pet owners and industry members to contact members of the judicial committee and request they seek expert input before acting on the proposed legislation. During Tuesday's subcommittee markup meeting, one committee member noted that they lacked sufficient knowledge on the issue to offer appropriate amendments, according to PIJAC. PIJAC also notes the legislation bypasses the statuary listing process included in the Lacey Act. That process requires the U.S. Fish and Wildlife Service to conduct a risk analysis and seek public comment before listing a species as “injurious.” The Fish and Wildlife Service is currently conducting such an analysis, PIJAC reports. PIJAC warned concerned pet owners that the legislation, if passed as written, would set a dangerous precedent of adding controversial species to the Lacey Act without hearings and sufficient study. That precedent could affect owners of other pets, including birds, fish and turtles, PIJAC reported. PIJAC urged concerned industry members to immediately contact every member of the committee because: * As drafted, the legislation would affect tens of thousands of pet owners and business owners; * There is no scientific justification for a broad ban and that Congress should not circumvent the Fish and Wildlife Service’s ongoing risk analysis; * Legislation should include resources for dealing with existing populations of Burmese pythons in the Everglades; * A ban of Burmese pythons should be limited to importation of the species into the United States; * Legislation should include provisions to allow for interstate movement of Burmese pythons subject to meeting housing and management practices; * And Legislation should include provisions for financial support to the Fish and Wildlife Service and partners, including PIJAC, to expand the Habitattitude campaign to educate reptile owners not to release unwanted pets. Source: http://www.petproductnews.com/headlines/2009/07/27/house-judiciary-committee-to-hear-python-ban-bill.aspx

House Judiciary Committee Amends, Passes Python Bill The House Judiciary Committee on July 29 amended and passed HR 2811, a bill that would add Burmese pythons and African rock pythons to the Lacey Act as injurious species. The bill, which would have added all pythons as originally written, now moves to the full House, which is not expected to act on it until September at the earliest, after its August recess. If the bill passes into law, the Lacey Act would prohibit the import, export and interstate movement of the two python species. Reptile keepers, including the U.S. Association of Reptile Keepers, and pet industry members are expected to continue to work with legislators in an effort to further amend the bill to limit its trade restrictions to the importing of the two species. This would protect the existing commercial trade of captive-bred pythons. The amendment, offered by Rep. Thomas Rooney (R-Fla), replaced the phrase “of the constrictor snake of the species Python genera” with the phrase “of the Burmese python of the species Python molurus bivattatus; of the African Rock Python of the species Python sebae.” A related bill, S. 373, still sits in a Senate committee as originally written. Even with the amendment, the bill would bypass the statuary listing process included in the Lacey Act, according to the Pet Industry Joint Advisory Council. That process requires the U.S. Fish and Wildlife Service to conduct a risk analysis and seek public comment before listing a species as “injurious.” The Fish and Wildlife Service is currently conducting such an analysis, PIJAC reports. PIJAC warned concerned pet owners that the legislation, if passed as written, would set a dangerous precedent of adding controversial species to the Lacey Act without hearings and sufficient study. That precedent could affect owners of other pets, including birds, fish and turtles, PIJAC reported. Source: http://www.petproductnews.com/headlines/2009/07/29/house-judiciary-committee-amends-passes-python-bill.aspx