Editing Frog (section)

====Metamorphosis====
At the end of the tadpole stage, a frog undergoes metamorphosis in which its body makes a sudden transition into the adult form. This metamorphosis typically lasts only 24 hours, and is initiated by production of the [[hormone]] [[thyroxine]]. This causes different tissues to develop in different ways. The principal changes that take place include the development of the lungs and the disappearance of the gills and gill pouch, making the front legs visible. The lower jaw transforms into the big mandible of the carnivorous adult, and the long, spiral gut of the herbivorous tadpole is replaced by the typical short gut of a predator.<ref name=Stebbins2/> Homeostatic feedback control of food intake is largely absent, making tadpoles eat constantly when food is present. But shortly before and during metamorphosis the sensation of hunger is suppressed, and they stop eating while their gut and internal organs are reorganised and prepared for a different diet.<ref>{{cite journal | pmc=5897637 | year=2018 | last1=Bender | first1=M. C. | last2=Hu | first2=C. | last3=Pelletier | first3=C. | last4=Denver | first4=R. J. | title=To eat or not to eat: Ontogeny of hypothalamic feeding controls and a role for leptin in modulating life-history transition in amphibian tadpoles | journal=Proceedings. Biological Sciences | volume=285 | issue=1875 | doi=10.1098/rspb.2017.2784 | pmid=29593109 }}</ref><ref>[https://www.futurity.org/tadpoles-leptin-metamorphosis-1720852-2/ Tadpoles eat like crazy before remodeling their guts - Futurity]</ref> Also the [[gut microbiota]] changes, from being similar to that of fish to resembling that of amniotes.<ref>{{cite journal | url=https://pubmed.ncbi.nlm.nih.gov/24249298/ | pmid=24249298 | year=2013 | last1=Kohl | first1=K. D. | last2=Cary | first2=T. L. | last3=Karasov | first3=W. H. | last4=Dearing | first4=M. D. | title=Restructuring of the amphibian gut microbiota through metamorphosis | journal=Environmental Microbiology Reports | volume=5 | issue=6 | pages=899–903 | doi=10.1111/1758-2229.12092 | bibcode=2013EnvMR...5..899K }}</ref> Exceptions are carnivorous tadpoles like [[Lepidobatrachus laevis]], which has a gut already adapted to a diet similar to that of adults. These continue to eat during metamorphosis.<ref>{{cite journal | doi=10.1186/s12861-020-00221-5 | title=Evolutionary and developmental considerations of the diet and gut morphology in ceratophryid tadpoles (Anura) | year=2020 | last1=Fabrezi | first1=Marissa | last2=Cruz | first2=Julio César | journal=BMC Developmental Biology | volume=20 | issue=1 | page=16 | pmid=32723314 | s2cid=255787646 | pmc=7388516 | doi-access=free }}</ref> The nervous system becomes adapted for hearing and stereoscopic vision, and for new methods of locomotion and feeding.<ref name=Stebbins2/> The eyes are repositioned higher up on the head and the eyelids and associated glands are formed. The eardrum, middle ear, and inner ear are developed. The skin becomes thicker and tougher, the lateral line system is lost, and skin glands are developed.<ref name=Stebbins2/> The final stage is the disappearance of the tail, but this takes place rather later, the tissue being used to produce a spurt of growth in the limbs.<ref>{{cite encyclopedia |url=https://www.britannica.com/EBchecked/topic/25677/animal-development/63769/Metamorphosis |title=Animal development: Metamorphosis |last1=Balinsky |first1=Boris Ivan |encyclopedia=Encyclopædia Britannica |access-date=August 10, 2012}}</ref> Frogs are at their most vulnerable to predators when they are undergoing metamorphosis. At this time, the tail is being lost and locomotion by means of limbs is only just becoming established.<ref name=Britannica/>

{{gallery
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|File:RanaTemporariaLarva2.jpg|Larva of the common frog ''Rana temporaria'' a day before metamorphosis
|File:Rana Temporaria - Larva Final Stage.jpg|Metamorphosis stage with deforming jaws, large eyes, and remains of gill pouch
|File:Juvenile Frog with tail top view (1).JPG|Young frog with a stumpy tail, metamorphosis nearly complete
}}