Search results
Results from the WOW.Com Content Network
A great cormorant swimming. Aquatic locomotion or swimming is biologically propelled motion through a liquid medium. The simplest propulsive systems are composed of cilia and flagella. Swimming has evolved a number of times in a range of organisms including arthropods, fish, molluscs, amphibians, reptiles, birds, and mammals.
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 can be separated into four main groups according to their positions within the water column. Neustons ("floaters"), more specifically the zooneustons , inhabit the surface ecosystem and use buoyancy to stay at the water surface , sometimes with appendages hanging from the underside for foraging (e.g. Portuguese man o' war ...
Species that do need to swim continuously to breathe go through a process known as sleep swimming, in which the shark is essentially unconscious. It is known from experiments conducted on the spiny dogfish that its spinal cord , rather than its brain, coordinates swimming, so spiny dogfish can continue to swim while sleeping, and this also may ...
To aid in swimming, their tails are slightly flattened vertically, [14] a shape that is unique to them. [15] When they walk on land, their tails drag on the ground, which makes their tracks easy to recognize. [6] [7] Muskrats spend most of their time in water and are well suited to their semiaquatic life. They can swim underwater for 12 to 17 ...
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 ...
At about 1–2 years old the young may voluntarily swim in shallow water and tide pools, but they do not dive. [63] Marine iguanas can dive as deep as 30 m (98 ft), [9] and can spend up to one hour underwater. [21] When diving to 7 m (23 ft) or deeper, they regularly remain submerged from 15 to more than 30 minutes. [64]
Unlike flying, however, swimming animals do not necessarily need to actively exert high vertical forces because the effect of buoyancy can counter the downward pull of gravity, allowing these animals to float without much effort. While there is great diversity in fish locomotion, swimming behavior can be classified into two distinct "modes ...