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Article Evaluation
This is a review for Cannibalism in poultry

The article talks about the cannibalistic behaviour in poultry where an individual will consume another of the same species because of feather pecking or vent pecking in domestic chicken, turkeys and pheasants. The article touches on a lot of points such as why this behaviour develops, how often it occurs and how to control it. Overall the article does a good job to convey the information in an unbiased manner. However, in the Development section it says how the feather pecking and cannibalism in brooded chicks had a lower mortality and may indicate how the hen influences the chick’s behaviour. Which seems like a conclusion the author came up with from the article and is not unbiased. Also, most facts are also only backed up by one source so It would be more helpful to have multiple sources with the same findings to increase the validity of the statements. The talk page does not have much discussion relevant to the contents of the article, just how the article should be named. The article is part of WikiProject Birds,  WikiProject Agriculture and WikiProject Veterinary medicine as a Start-Class project with low- mid importance. This shows how the article has some room for expansion and improvement. The causes of cannibalism could be expanded on such as including prolapse pecking, the differences between fast and slow feathering birds and how leaving injured birds in the flock may influence the prevalence of cannibalism in the flock. There also is no section on the treatment for a cannibalism outbreak, just methods of control as a preventive measure but nothing on what is done when there is cannibalism happening.

Draft Article
This article is a stub article of low importance which no useful information or advice listed.

There is a limited amount of information currently existing that is cited and it provides multiple examples of animals that have this feeding behaviour, which will be expanded on.

The article definition that already exists will be expanded on to also include the bamboo eaters that are mentioned in the second part of the existing article.

bone crackers and bamboo eaters : this will expand mostly on the bamboo eaters (red and giant pandas). I will include the significance of their behaviour and expand more on their jaw morphology and what gives them the ability to eat bamboo. Also, the required gut physiology that is needed to digest their food.

adaptation in extinct animals: will give early evolutionary evidence to durophagy and the mechanisms that have evolved to make this feeding behaviour possible.

Adaptations in fish - how they break the hard shells of their prey and digest them, with predator behaviour and capture explained.

Adaptations in reptiles -  with a specific focus on the adaptations in turtles and what their predatory behaviour is as well as the jaw adaptations needed to capture and eat their prey

Adaptations In mammals -  I will be expanding on the bone crushers part of the article that already exists, adding information to hyenas and saber-toothed cats which are mentioned. The behaviours and jaw morphology adaptations will be added.

Bibliography:

may be subject to change

Marshall, Christopher D.; Guzman, Alejandra; Narazaki, Tomoko; Sato, Katsufumi; Kane, Emily A.; Sterba-Boatwright, Blair D. (2012-12-01). "The ontogenetic scaling of bite force and head size in loggerhead sea turtles (Caretta caretta): implications for durophagy in neritic, benthic habitats". Journal of Experimental Biology. 215 (23): 4166–4174. doi:10.1242/jeb.074385. ISSN 0022-0949. PMID 22899532.

Hartstone-Rose, Adam; Steynder, Deano D. (2013-05-01). "Hypercarnivory, durophagy or generalised carnivory in the Mio-Pliocene hyaenids of South Africa? : research article" (PDF). South African Journal of Science. 109 (5-6). ISSN 0038-2353.

Miranda, Everton B.P.; Menezes, Jorge F.S. de; Rheingantz, Marcelo L. "Reptiles as principal prey? Adaptations for durophagy and prey selection by jaguar (Panthera onca)". Journal of Natural History. 50 (31-32): 2021–2035. doi:10.1080/00222933.2016.1180717.

Gidmark, Nicholas J.; Taylor, Chantel; LoPresti, Eric; Brainerd, Elizabeth (2015-12-01). "Functional morphology of durophagy in black carp, Mylopharyngodon piceus". Journal of Morphology. 276 (12): 1422–1432. doi:10.1002/jmor.20430. ISSN 1097-4687.

Quantifying the Evolution of Early Life | SpringerLink. doi:10.1007/978-94-007-0680-4.

Encyclopedia of fish physiology : from genome to environment. Farrell, Anthony Peter, 1952-, Stevens, E. Donald (Ernest Donald),, Cech, Joseph J.,, Richards, Jeffrey G.,. London. ISBN 9780123745453. OCLC 741502398.

= Article Draft =

Durophagy is the eating behavior of animals that consume hard-shelled or exoskeleton bearing organisms, such as corals, shelled mollusks, or crabs. It is mostly used to describe fish, but is also used when describing reptiles, including fossil turtles , placodonts and invertebrates, as well as "bone-crushing" mammalian carnivores such as hyenas. Durophagy requires special adaptions, such as blunt, strong teeth and a heavy jaw. Bite force is necessary to overcome the physical constraints of consuming more durable prey and gain a competitive advantage over other organisms by gaining access to more diverse or exclusive food resources earlier in life. Those with greater bite forces require less time to consume certain prey items as a greater bite force can increase the net rate of energy intake when foraging and enhance fitness in durophagous species. In the order Carnivora there are two dietary categories of durophagy; bonecrackers and bamboo eaters. Bonecrackers are exemplified by hyenas and saber-toothed cats, while bamboo eaters are primarily the giant panda and the red panda. Both have developed similar cranial morphology. However, the mandible morphology reveals more about their dietary resources. Both have a raised and dome-like anterior cranial, enlarged areas for the attachment of masticatory muscles, enlarged premolars, and reinforced tooth enamel. Bamboo eaters tend to larger mandibles, while bonecrackers have more sophisticated premolars.

Fish
Many fish exhibit durophagous behaviour including the Triggerfish, some Teleosts and some cichlids.

Triggerfish (Balistidae)
Triggerfish have jaws that contain a row of four teeth on either side, the upper jaw containing an additional set of six plate-like pharyngeal teeth. Triggerfish do not have jaw protrusion and there are enlarged jaw adductor muscles for extra power to crush the protective shells and spines of their prey.

Teleost (Teleostei)
These fishes that crush hard prey do so with the use of their pharyngeal jaws, with the aid of their protrusible mouth for enabling the grabbing of prey to draw in into their mouth. The pharyngeal jaws in the more derived teleosts are more powerful, with left and right ceratobranchials fusing to become one lower jaw and the pharyngeal branchial fuse to create a large upper jaw that articulates with the neurocranium. They have also developed a muscle, the hypertrophied pharyngeal, to crush the prey with the help of the molariform pharyngeal teeth. Allowing for the consumption of hard shelled prey.

Cichlids (Cichlidae)
The mollusk shell can be crushed to expose the soft parts of the prey to digestive juices or the soft parts can be removed from the shell. Species that crush the shell are defined by their large and greatly thickened pharyngeal bones. These bones have flat-crowned teeth and along with their dorsal fellows drawn by powerful muscles, create a crushing mill. The jaws are less derived as they are for just for picking up relatively large objects.

The second method is to crush their shells between powerful jaws armed with suitable teeth. They possess short, broad jaws armed with an outer row of relatively few, strong and conical teeth, and several inner rows of finer, also conical teeth. With these features are the presence of foreshortening of the skull and development of particularly powerful mandibular adductor muscles. To feed with this type of structure the fish can protrude its mouth ventrally to permit muscles to be seized by the jaws and is retracted rapidly so the hard-toothed jaws crush the shell of the mollusk with the resulting force. A series of biting movements completes the process and the shell fragments are spat out and the soft body swallowed.

Chondrichthyans
Within the Chondrichthyans, horn sharks (Heterodontidae), some rays (Myliobatidae) and chimeras (Holocephali) exhibit durophagous behaviour. They have adaptations to allow for this, including stout flattened teeth, hypertrophied jaw adductor muscles and robust jaws to feed on hard prey, such as crustaceans and molluscs. Sharks that crush prey have teeth that have small, low rounded cusps that are numerous per row, or are molariform. The molariform teeth are smoothly rounded and lack cusps, and there are numerous teeth per row.

Horn sharks (Heterodontiformes)
They have molariform teeth. The anterior teeth are pointed and used for grasping, and the posterior teeth are molariform and used for crushing. Horn sharks feed primarily on limpets, bivalve molluscs and blue crabs.

Bonnethead Shark (Sphyrna tiburo)
The bonnethead shark Sphyrna tiburo uses ram feeding to capture crab, shrimp and fish which are placed between the molariform teeth where they are crushed. This species also uses suction to transport prey to the esophagus for swallowing. By combining durophagous characteristics with altered kinematic and motor patterns it can prey on hard shelled animals. This characteristic distinguishes prey crushing from simply biting in elasmobranchs. While bonnethead sharks feed almost exclusively on crabs, they have the same tooth structure as the Horn sharks (Heterodontiformes).

Chimeras (Holocephali)
Chimeras (Holocephali) have pavement teeth that are flat, hexagonal in shape and interconnect to form an even dental plate. There is the presence of calcified strengthened cartilaginous jaws, calcified struts within the jaws and a lever ‘nutcracker’ system that amplifies the force of the jaw adductor muscles. The fusion of the palatoquadrate and mandibular symphysis, a restricted gape and asynchronous activation of the jaw adductors are key elements in the ‘nutcracker’ model of jaw-crushing ability. They use their pavement teeth for grinding molluscs, gastropods and crabs.

Myliobatidae
Myliobatidae are free-swimming rays whose pectoral fins make up broad, powerful “wings” which include the eagle and cow-nose rays. They feed on molluscs and have dentitions adapted to crushing. The dentitions of the durophagous myliobatids show several specializations in the jaws and teeth related to their diet. The cartilaginous jaws are strengthened by calcified struts (trabeculae), and the palatoquadrate and mandibular symphysis are fused. Strong ligaments connecting the upper and lower jaws restrict the gape. The strong adductor muscles can be asynchronously activated.

Eagle (Aetobatus narinari) and cow-nose (Rhinoptera javanica) rays
The teeth are hexagonal and arranged in anteroposterior files packed closely together in an alternating array to form an almost gap-free pavement, similar to the Chimeras. The teeth are covered with a layer of enameloid. The tooth pavement is stabilized by the vertical surfaces that bear ridges and grooves which are interconnected with those on neighboring teeth.They also use their pavement teeth for grinding molluscs, gastropods and crabs. Cow nose are specialized suction feeders, which open and close their jaws to generate water movements that are used to excavate buried prey. Food capture is achieved by suction and the prey is then cleaned by actions similar to those used in excavation.

Myliobatis and Aetobatus
Anteroposterior ridges of the basal plate extend from the posterior margin of the tooth which these interdigitate with those of the succeeding tooth and also form a shelf on which the body of the neighboring tooth rests. The dentition of the bat ray (Myliobatis californica) is made up of a series of seven files of crushing teeth. The central hexagonal plate is very wide, taking up about half the width of the occlusal surface and it is flanked by three lateral files of smaller teeth on each side, the outermost being pentagonal. The crushing surface formed by the teeth of the upper jaw is more curved than that of the lower jaw.

Birds
Shorebirds commonly consume bivalves and snail which are low in chitin but the calcium carbonate shell makes up a large portion of their weight which is largely consumed whole by ducks and wading birds. The mollusivoires that swallow snails or bivalves whole have large well-modularized gizzards for crushing the strong shells. The gizzard of red-necked stints and red knots is more than ten times larger than the proventriculus. The size of the gizzard is adaptable in these shore birds, becoming atrophied when soft food items like worms are consumed and increase in size and muscularity following prolonged consumption of snails, cockles or mussels. The production of chitinase for the hydrolysis of chitin is important for birds that consume some mollusks.

Sea Otters (Enhydra lutris)
Sea otters preferentially forage on benthic invertebrates, particularly sea urchins, gastropod, bivalve mollusks, and crustaceans. Once prey is caught, they use their powerful jaws and sharp teeth to make short work of their meal, even crustaceans. They have canines that deliver a lethal bite, and molars that can crush bones and the shells of mollusks.

The molars are broad, flat, multi cuspid teeth and the carnassial are also modified for crushing, both temporalis and masseter muscles are well developed creating a strong bite force. The teeth are extremely broad and carnassial are highly molarized. Captured prey is manipulated with the forepaws or is held temporarily in loose skin pouches in the armpits. For larger, heavier-shelled prey, otters will sometimes exhibit tool-use behavior, breaking open sea urchins and mussels by a false stone, used as an anvil. They can also bite them open using their strong jaws and teeth. Adults can crush most of their food items but youngsters have not yet developed powerful enough jaws. Therefore, they acquire the assistance of a tool/ stone. Tools may also be used when the molluscs are too large to be cursed in the jaws.

Monkeys
All mangabeys appear to be durophagous and possess relatively thick molar enamel and expanded premolars) dental adaptations for processing hard foods. Their diet consists of of Sacoglottis gabonensis seeds. These seeds, which can remain on the ground for months without rotting. With the hard- object feeding they needed selection to favour thick molar enamel and flattened molars for crushing the seeds.

Giant panda
The giant panda is mainly a herbivore, despite its short, relatively unspecialized digestive tract of carnivores. They lack the microbial digestion in rumen or caecum that is typical of most herbivores for breaking down cellulose and lignin in plant cell walls. So they need to get their nutrients from the cell contents and the fraction of hemicellulose it can break down. The panda subsits mainly on bamboo and does so with the modifications of their jaws. The pandas show elaboration of the crushing features of the dentition. The molars are broad, flat, multi cuspid teeth. The molars are the main grinding surface. The jaw action is not a simple crushing one but a definite sideways grinding. They have a large zygomatico-mandibularis muscle, which is responsible for the sideways movement of the jaw. The glenoid is very deep, preventing the back and forth movement of the jaw.

Bamboo represents a predictable food source, which are seasonally abundant and the nutritional value remains constant all year, which lead the panda to be able to subsist on it, despite its low nutritive content. It does this by moving large quantities through the digestive tract in a short period of time. They also reduce their energy expenditures by resting and only remaining ative to feed and they don’t have hibernation period to allow for more foraging time. They chose security over uncertainty, allowing for the current bamboo eating adaptations.

Hyaenids
Bone-crushing eating habits appear to be associated with stronger teeth, as seen in hyaenids. Because bone-crushing requires greater bite strength and increases risk of canine breakage.The carnassial are slightly less specialized as cutting blades then those of the Felidae. The bone-crushing adaptations relate mainly to the premolars. The anterior and posterior cusps are reduced and the central cusp enlarged and widened, so that the tooth is converted from a blade-like structure to a heavy conical hammer. Strong muscles are also required for bone crushing, and the temporalis attachment on the skull is enlarged by a strong sagittal crest. Heavy- hammer like teeth and extremely strong jaws and jaw muscles make it possible for hyaenas to crack larger bone than other carnivores can cope with and their highly efficient cutting carnassials can deal with tough hides and tendons.

Wolverine (Gulo gulo)
The wolverine has jaws and teeth that are extremely powerful and together with its scavenging habits, have earned the wolverine the name “hyena of the north”. The wolverine is an effective scavenger, capable of cracking heavy bones and shows the same adaptations in the jaw as the hyenas do. The sagittal crest project well above the area of attachment of the neck muscles, and in a large animal it extends back far behind the level of the condyles to provide attachments for the relatively enormous temporalis muscles, creating a powerful bite force.

The sabre-tooth's
In addition to their enlarged canine teeth, they had the most specialized slicing carnassial teeth in the whole carnivore history but their anterior premolars were extremely reduced. This indicates the ability to cut through flesh with the greatest efficiency, but could not have crushed the bones of anything larger than a chicken. This would have left splendid pickings for species that could crush the bones of anything larger than a chicken. Leading to the evolution of the hyenas. The contrast between the hyenas and the saber- tooth jaw is striking, with the heavy and hammer-like premolars of the one and the vestigial character of the same teeth in the other. The Hyenas became experts in bone crushing at a time when the dominant cats were saber-tooth’s and bones to scavenge were more easily come by then they are today.