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Swimming animals that are denser than water must generate lift or adapt a benthic lifestyle. Movement of the fish to generate hydrodynamic lift is necessary to prevent sinking. Often, their bodies act as hydrofoils, a task that is more effective in flat-bodied fish. At a small tilt angle, the lift is greater for flat fish than it is for fish ...
Wading and bottom-feeding animals (e.g. moose and manatee) need to be heavier than water in order to keep contact with the floor or to stay submerged, surface-living animals (e.g. otters) need the opposite, and free-swimming animals living in open waters (e.g. dolphins) need to be neutrally buoyant in order to be able to swim up and down the ...
Aquatic animals generally conduct gas exchange in water by extracting dissolved oxygen via specialised respiratory organs called gills, through the skin or across enteral mucosae, although some are evolved from terrestrial ancestors that re-adapted to aquatic environments (e.g. marine reptiles and marine mammals), in which case they actually ...
Organisms such as jellyfish and others are considered plankton when they are very small and swim at low Reynolds numbers, and considered nekton as they grow large enough to swim at high Reynolds numbers. Many animals considered classic examples of nekton (e.g., Mola mola, squid, marlin) start out life as tiny members of the plankton and then ...
Grayia smythii (Smith's African water snake) Homalopsidae (Bockadams) [1] Bitia hydroides (Keel-bellied water snake) Cantoria violacea (Cantor's water snake) Cerberus (Dog-faced water snakes) Cerberus australis Cerberus dunsoni Cerberus microlepis Cerberus rynchops Cerberus schneiderii. Djokoiskandarus annulata (Banded water snake) Myrrophis
It has been suggested that young iguanas up to about two years old are unable to swim, [52] but studies have shown that even newly hatched marine iguanas are good swimmers; they just strongly try to avoid entering the water. [61] At about 1–2 years old the young may voluntarily swim in shallow water and tide pools, but they do not dive. [61]
Surface-living animals (such as sea otters) need the opposite, and free-swimming animals living in open waters (such as dolphins) need to be neutrally buoyant in order to be able to swim up and down the water column. Typically, thick and dense bone is found in bottom feeders and low bone density is associated with mammals living in deep water.
Swimming mammals, such as whales, dolphins, and seals, use their flippers to move forward through the water column. During swimming sea lions have a thrust phase, which lasts about 60% of the full cycle, and the recovery phase lasts the remaining 40%. A full cycle duration lasts about 0.5 to 1.0 seconds. [3]