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Alligator and bites

Kaleb C Sellers, Kevin M Middleton, Julian L Davis, Casey M Holliday
Three-dimensional computational modeling offers tools with which to investigate forces experienced by the skull encountered during feeding and other behaviors. American alligators (Alligator mississippiensis) generate some of the highest measured bite forces among extant tetrapods. A concomitant increase in bite force accompanies ontogenetic increases in body mass, which has been linked with dietary changes as animals increase in size. Because the flattened skull of crocodylians has substantial mediolaterally-oriented muscles, they are an excellent model taxon in which to explore the role of mediolateral force components experienced by the feeding apparatus...
March 31, 2017: Journal of Experimental Biology
Vincent R Sherman, Haocheng Quan, Wen Yang, Robert O Ritchie, Marc A Meyers
We compare the characteristics of the armored scales of three large fish, namely the Arapaima gigas (arapaima), Latimeria chalumnae (coelacanth), and Atractosteus spatula (alligator gar), with specific focus on their unique structure-mechanical property relationships and their specialized ability to provide protection from predatory pressures, with the ultimate goal of providing bio-inspiration for manmade materials. The arapaima has flexible and overlapping cycloid scales which consist of a tough Bouligand-type arrangement of collagen layers in the base and a hard external mineralized surface, protecting it from piranha, a predator with extremely sharp teeth...
September 2017: Journal of the Mechanical Behavior of Biomedical Materials
Robert D Johnson, Cynthia L Nielsen
Legend states that the alligator snapping turtle (Macrochelys temminckii) should be handled with extreme caution as it has jaw strength powerful enough to bite a wooden broomstick in half. Tales of bite injuries from what is the largest freshwater turtle in North America exist anecdotally, yet there are few descriptions of medical encounters for such. The risk of infection from reptilian bites to the hand in an aquatic environment warrants thorough antibiotic treatment in conjunction with hand surgery consultation...
June 2016: Wilderness & Environmental Medicine
Ben Achrai, H Daniel Wagner
Biological structures consisting of strong boney elements interconnected by compliant but tough collagenous sutures are abundantly found in skulls and shells of, among others, armadillos, alligators, turtles and more. In the turtle shell, a unique arrangement of alternating rigid (rib) and flexible (suture) elements gives rise to superior mechanical performance when subjected to low and high strain-rate loadings. However, the resistance to repeated load cycling - fatigue - of the turtle shell has yet to be examined...
August 2015: Materials Science & Engineering. C, Materials for Biological Applications
Zhiheng Li, Julia A Clarke
Anatomical studies of the cranium of crocodilians motivated by an interest in its function in feeding largely focused on bite force, the jaw apparatus and associated muscles innervated by the trigeminal nerve. However, the ossified and cartilaginous elements of the hyoid and the associated hyolingual muscles, innervated by the facial, hypoglossal and glossopharyngeal nerves, received much less attention. Crocodilians are known to retain what are ancestrally the 'Rhythmic Hyobranchial Behaviors' such as buccal oscillation, but show diminished freedom and movement for the hyobranchial apparatus and the tongue in food transport and manipulation...
July 2015: Journal of Anatomy
Laura B Porro, Callum F Ross, Jose Iriarte-Diaz, James C O'Reilly, Susan E Evans, Michael J Fagan
In vivo bone strain data are the most direct evidence of deformation and strain regimes in the vertebrate cranium during feeding and can provide important insights into skull morphology. Strain data have been collected during feeding across a wide range of mammals; in contrast, in vivo cranial bone strain data have been collected from few sauropsid taxa. Here we present bone strain data recorded from the jugal of the herbivorous agamid lizard Uromastyx geyri along with simultaneously recorded bite force. Principal and shear strain magnitudes in Uromastyx geyri were lower than cranial bone strains recorded in Alligator mississippiensis, but higher than those reported from herbivorous mammals...
June 1, 2014: Journal of Experimental Biology
Laura B Porro, Keith A Metzger, Jose Iriarte-Diaz, Callum F Ross
Forces experienced during feeding are thought to strongly influence the morphology of the vertebrate mandible; in vivo strain data are the most direct evidence for deformation of the mandible induced by these loading regimes. Although many studies have documented bone strains in the mammalian mandible, no information is available on strain magnitudes, orientations or patterns in the sauropsid lower jaw during feeding. Furthermore, strain gage experiments record the mechanical response of bone at a few locations, not across the entire mandible...
September 2013: Journal of Anatomy
Daniel Dashevsky, Jesse M Meik, Estrella Mociño-Deloya, Kirk Setser, Sarah Schaack
We compare morphological characteristics of male and female Barisia imbricata, Mexican alligator lizards, and find that mass, head length, coloration, incidence of scars from conspecifics, tail loss, and frequency of bearing the color/pattern of the opposite sex are all sexually dimorphic traits. Overall size (measured as snout-vent length), on the other hand, is not different between the two sexes. We use data on bite scar frequency and fecundity to evaluate competing hypotheses regarding the selective forces driving these patterns...
February 2013: Ecology and Evolution
Christopher W Walmsley, Peter D Smits, Michelle R Quayle, Matthew R McCurry, Heather S Richards, Christopher C Oldfield, Stephen Wroe, Phillip D Clausen, Colin R McHenry
BACKGROUND: Crocodilians exhibit a spectrum of rostral shape from long snouted (longirostrine), through to short snouted (brevirostrine) morphologies. The proportional length of the mandibular symphysis correlates consistently with rostral shape, forming as much as 50% of the mandible's length in longirostrine forms, but 10% in brevirostrine crocodilians. Here we analyse the structural consequences of an elongate mandibular symphysis in relation to feeding behaviours. METHODS/PRINCIPAL FINDINGS: Simple beam and high resolution Finite Element (FE) models of seven species of crocodile were analysed under loads simulating biting, shaking and twisting...
2013: PloS One
Narges Askari, Afrooz Eshaghian
Leeches are blood-sucking hermaphroditic parasites that attach to vertebrate hosts, bite through the skin, and suck out blood. When leeches feed, they secrete an anticoagulant (hirudin), which helps them get a full meal of blood. This is the first report of leech removal from external auditory canal. Previous leech involvement cases were explained in nasopharynx, larynx, pharynx, eye, and gastrointestinal tract. Prominent sign of all cases was active bleeding from the leech attachment site; that stopped with leech removal...
2012: Advanced Biomedical Research
Mark T Young, Stephen L Brusatte, Marco Brandalise de Andrade, Julia B Desojo, Brian L Beatty, Lorna Steel, Marta S Fernández, Manabu Sakamoto, Jose Ignacio Ruiz-Omeñaca, Rainer R Schoch
BACKGROUND: Dakosaurus and Plesiosuchus are characteristic genera of aquatic, large-bodied, macrophagous metriorhynchid crocodylomorphs. Recent studies show that these genera were apex predators in marine ecosystems during the latter part of the Late Jurassic, with robust skulls and strong bite forces optimized for feeding on large prey. METHODOLOGY/PRINCIPAL FINDINGS: Here we present comprehensive osteological descriptions and systematic revisions of the type species of both genera, and in doing so we resurrect the genus Plesiosuchus for the species Dakosaurus manselii...
2012: PloS One
Augustine George, Seong K Lee, Eddy H Carrillo
No abstract text is available yet for this article.
March 2012: Journal of Trauma and Acute Care Surgery
Gregory M Erickson, Paul M Gignac, Scott J Steppan, A Kristopher Lappin, Kent A Vliet, John D Brueggen, Brian D Inouye, David Kledzik, Grahame J W Webb
BACKGROUND: Crocodilians have dominated predatory niches at the water-land interface for over 85 million years. Like their ancestors, living species show substantial variation in their jaw proportions, dental form and body size. These differences are often assumed to reflect anatomical specialization related to feeding and niche occupation, but quantified data are scant. How these factors relate to biomechanical performance during feeding and their relevance to crocodilian evolutionary success are not known...
2012: PloS One
Pierre Charruau, Jonathan Pérez-Flores, José G Pérez-Juárez, J Rogelio Cedeño-Vázquez, Rebeca Rosas-Carmona
Bacterial cultures and chemical analyses were performed from cloacal and oral swabs taken from 43 American crocodiles Crocodylus acutus and 28 Morelet's crocodiles C. moreletii captured in Quintana Roo State, Mexico. We recovered 47 bacterial species (28 genera and 14 families) from all samples with 51.1% of these belonging to the family Enterobacteriaceae. Fourteen species (29.8%) were detected in both crocodile species and 18 (38.3%) and 15 (31.9%) species were only detected in American and Morelet's crocodiles, respectively...
February 17, 2012: Diseases of Aquatic Organisms
K T Bates, P L Falkingham
Bite mechanics and feeding behaviour in Tyrannosaurus rex are controversial. Some contend that a modest bite mechanically limited T. rex to scavenging, while others argue that high bite forces facilitated a predatory mode of life. We use dynamic musculoskeletal models to simulate maximal biting in T. rex. Models predict that adult T. rex generated sustained bite forces of 35 000-57 000 N at a single posterior tooth, by far the highest bite forces estimated for any terrestrial animal. Scaling analyses suggest that adult T...
August 23, 2012: Biology Letters
Danielle Bury, Neil Langlois, Roger W Byard
Animals may be responsible for an array of potentially lethal injuries. Blunt force injuries characteristically involve larger animals such as cattle or horses that may kick, crush, or trample a victim causing head and facial injuries. Farm workers in particular are at high risk of lethal injuries involving the head and torso. Significant blunt trauma may be found in vehicle occupants after collisions with large animals such as camels or moose. Rarely, zookeepers may be crushed by particularly massive animals such as elephants...
March 2012: Journal of Forensic Sciences
Fredrick M Abrahamian, Ellie J C Goldstein
The microbiology of animal bite wound infections in humans is often polymicrobial, with a broad mixture of aerobic and anaerobic microorganisms. Bacteria recovered from infected bite wounds are most often reflective of the oral flora of the biting animal, which can also be influenced by the microbiome of their ingested prey and other foods. Bacteria may also originate from the victim's own skin or the physical environment at the time of injury. Our review has focused on bite wound infections in humans from dogs, cats, and a variety of other animals such as monkeys, bears, pigs, ferrets, horses, sheep, Tasmanian devils, snakes, Komodo dragons, monitor lizards, iguanas, alligators/crocodiles, rats, guinea pigs, hamsters, prairie dogs, swans, and sharks...
April 2011: Clinical Microbiology Reviews
Vidal Haddad, Waldicléa Cardoso Fonseca
We describe a fatal attack by a black caiman (Melanosuchus niger) on an 11-year-old child with comments on the reptile's aggression mechanisms and the conditions under which this kind of incident takes place in the Amazon region.
March 2011: Wilderness & Environmental Medicine
Lukman Yusuf, Sheferaw Negash
We present a case of vaginal calculus formation following an initial insult of female genital mutilation (FGM) and crocodile bite to the external genital. A literature review made with regards to acute and late complication of female genital mutilation. Female genital cutting existed as early as the 5th century B.C. This ritualistic practice has affected the physical, mental, and social well being of women and undermined the basic reproductive and sexual health rights of the female population. Worldwide, 85-114 million girls and young women are subjected to this dreadful practice...
April 2008: Ethiopian Medical Journal
Samuel J Fitzpatrick, Amanda L Thomas
No abstract text is available yet for this article.
December 6, 2010: Medical Journal of Australia
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