Frogfish have small, round gill openings behind their pectoral fins. With the exception of Butler's frogfish and the rough anglerfish, frogfish use a gas bladder to control their buoyancy. [ citation needed] Mimicry and camouflage [ edit ] A frogfish disguised as an algae-covered stone Frogs are used for dissections in high school and university anatomy classes, often first being injected with coloured substances to enhance contrasts among the biological systems. This practice is declining due to animal welfare concerns, and "digital frogs" are now available for virtual dissection. [219] Frogs are not found in the sea because frogspawn cannot survive saltwater; frogs are not found on small islands for the same reason. Reptiles, by contrast, frequently live in the sea, and even land reptiles can cross the sea. Adders, for instance, are found on several Hebridean islands, though not, of course, in Ireland – perhaps because if one happened to swim the North Channel it would never find another to mate with on such a large island.

Radhakrishnan, C.; Gopi, K. C. (2007). "Extension of range of distribution of Nasikabatrachus sahyadrensis Biju & Bossuyt ( Amphibia: Anura: Nasikabatrachidae ) along Western Ghats, with some insights into its bionomics" (PDF). Current Science. 92 (2): 213–216. ISSN 0011-3891. Archived (PDF) from the original on 2022-10-09.Laurin, Michel; Gauthier, Jacques A. (2012). "Amniota". Tree of Life Web Project . Retrieved 2012-08-04.

Although care of offspring is poorly understood in frogs, up to an estimated 20% of amphibian species may care for their young in some way. [170] The evolution of parental care in frogs is driven primarily by the size of the water body in which they breed. Those that breed in smaller water bodies tend to have greater and more complex parental care behaviour. [171] Because predation of eggs and larvae is high in large water bodies, some frog species started to lay their eggs on land. Once this happened, the desiccating terrestrial environment demands that one or both parents keep them moist to ensure their survival. [172] The subsequent need to transport hatched tadpoles to a water body required an even more intense form of parental care. [171] a b Froese, Rainer; Pauly, Daniel (eds.) (2009). " Histrio histrio " in FishBase. Sep 2009 version. Arboreal frogs have pads located on the ends of their toes to help grip vertical surfaces. These are not suction pads, the surface consisting instead of columnar cells with flat tops with small gaps between them lubricated by mucous glands. When the frog applies pressure, the cells adhere to irregularities on the surface and the grip is maintained through surface tension. This allows the frog to climb on smooth surfaces, but the system does not function efficiently when the pads are excessively wet. [53] In most cars 30mph will almost always burn less fuel for a given journey than 60mph. The energy (fuel) needed to get from A to B is primarily determined by two factors: the efficiency of the car's drive chain (engine, gearbox, differential etc) and external resistance to the car's movement.

Duellman, W. E. and L. Trueb (1986). Biology of Amphibians. New York: McGraw-Hill Publishing Company.

a b Minott, Kevin (2010-05-15). "How frogs jump". National Geographic. Archived from the original on 2013-11-04 . Retrieved 2012-06-10. Suthers, R.A.; Narins, P.M.; Lin, W; Schnitzler, H; Denzinger, A; Xu, C; Feng, A.S. (2006). "Voices of the dead: complex nonlinear vocal signals from the larynx of an ultrasonic frog". Journal of Experimental Biology. 209 (24): 4984–4993. doi: 10.1242/jeb.02594. PMID 17142687. Shubin, N. H.; Jenkins, F. A. Jr (1995). "An Early Jurassic jumping frog". Nature. 377 (6544): 49–52. Bibcode: 1995Natur.377...49S. doi: 10.1038/377049a0. S2CID 4308225.Meanwhile, the word toad, first attested as Old English tādige, is unique to English and is likewise of uncertain etymology. [14] It is the basis for the word tadpole, first attested as Middle English taddepol, apparently meaning 'toad-head'. [15] Taxonomy Few traces of frogfishes remain in the fossil record, though Antennarius monodi is known from the Miocene of Algeria and Eophryne barbuttii is known from the Eocene of Italy.