Fish And Things

most animals which live in water have special adaptations which assist them in moving more or less freely through it the fish's body is streamlined and equipped with powerful muscles for movement they also have several different kinds of fins which serve important purposes the pair at the front are used mostly to change the up and down direction of the body for turning to left and right for breaking and backing up the large fin in the mid region of the back helps to keep the fish from rolling over on its side or back it also helps to steady the fish on the course it is traveling the large tail fin assists in driving the fish forward by pushing sharply against the water and it is of great importance in steering but most of the force necessary for traveling comes from the curving of the body the curves are pushed at an angle against the surrounding water and drive the fish forward the fins of some fish are almost transparent nevertheless one can see that they are nearly always in motion when the fish rises in the water drops to a lower level or turns and darts off in a New Direction the smaller fins keep the fish in an upright position in the water no matter which way he maneuvers the entire body is covered with smooth overlapping scales permitting the fish to slip through the water with a minimum of effort eels lack most of the fins of fish they move almost entirely by curving the body against the water newts and salamanders possess partially webbed feet as well as long flexible well-muscled tails at times both tail and feet are used in swimming when only the tail is used the limbs are tucked in against the body making the whole animal more streamlined waves of motion are sent down the full length of the tail moving the Newt forward the tadpoles of frogs lack the limbs of newts they must move by means of the flat tail alone adult frogs have two pairs of legs for moving about however when swimming the front pair are held folded against the underside of the body the Frog pushes repeatedly against the water with strong Strokes of the webbed hind feet this kind of swimming is often referred to as the Frog stroke the super slow motion camera reveals that the long toes are brought close together on the upstroke but are broadly spread on the power stroke the webs are fully expanded and pushed against the Water by the powerful leg muscles Ducks too have webbed feet which they use as paddles they can swim slowly and easily forward using short Strokes on either side quick turns can be made by paddling on only one side they use the feet for diving and swimming underwater as well the colorful chick of the mud hand has very large feet with lobes or flaps on the sides of the toes the toes are partly folded on the forward stroke but spread to better push against the water on the backstroke they can really go horsehair worms may be several inches long but are only about as thick as a thread they move by turning twisting and stretching their long bodies strange as it may seem these Horse Air worms grow up inside water beetles round worms are found in enormous numbers wherever there is water they swim very rapidly by whipping the short curves of the body from side to side against the water mosquito regulars have a very strange method of swimming they usually hang upside down when the tail with its tuft of bristles is pushed sharply downwards the wriggler is pulled upward through the water he then pushes his breathing tube through the surface to take in air ghost midges are so transparent that you can see right through them a small fin on the end of the tail helps to whip the body into a tight Circle so that the midge can roll forward like a hoop before straightening out again damsel flies swim much like tadpoles and roundworms wriggling their bodies from side to side whirly gig beetles move so fast that the eye can hardly follow them even slowed down many times they failed to show us how they really swim round and round on the top of the water they probably use the two hind pair of legs which are flattened like paddles back swimmers have one pair of legs which are much longer than the rest this pair extends Sideways from the body like a long pair of oars the end of each Oar has a thick tuft of bristles which acts like the blade of a common paddle when the back swimmer rolls himself around though they move very fast at normal speed we can still see how the oars work round red mites have eight bristle covered lights for swimming rapidly crabs have 10 legs they use them for swimming sideways they generally use their many legs for crawling around under the water isopods sometimes jackknife the body to move more quickly when prawns swim they make use of their 10 legs their tail and the strange little paddles under the abdomen the shallow tide Waters of our coasts are swarming with many different kinds of animals shrimps of many kinds are very common swimming around among the eelgrass seaweed rocks and sand many of them are greenish in color because they have been eating smaller animals which live on seaweed they move largely by means of their five pairs of true legs up front together with the small leg-like growths further back on the underside when moving more quickly they often snap the body sharply using the broad flat tail at the rear the large sunflower starfish is sometimes found in shallow water turning one over shows the hundreds of two feet on the underside of its arms placing the starfish back in deeper water helps us to see how the two feet work each is filled with water and has a sort of Sucker on the end the starfish uses these unusual feet for moving about and for opening hard clam shells to get at the soft bodies of the clams inside the tube feet move freely permitting the starfish to make use of them in turning over and swimming slowly while working his way down the side of a rock he uses the suckers for gripping the surface as he continues downward he lets go with some of the feet while fastening on with others daphnia or water fleas often swarm in great numbers in shallow water fleas are one of the few animals in the world that swim with their antennae or feelers the forked antennae are pumped up and down lifting the water flea a little each stroke fairy shrimps are undoubtedly the most attractive little animals found in our ponds they are delicate fairy-like forms and almost unbelievably graceful flowing movement provide a site well worth seeking out each spring when they become active fairy shrimps often swim on their backs moving themselves forward by the waves of motion which Ripple down the feathery swimmerets from head to tail the eyes are on short Stalks at the sides of the head the females carry dark round egg sacs at the base of the tail they can move more quickly by quickly flicking the forked tail snails travel slowly from place to place on a broad flat foot moved by many small muscles the underside of a sea slug shows an even larger white foot surrounded by the body above it from above the slug is seen gliding slowly forward when the sides of the body are lifted slightly the edge of the foot comes into view the sea lemon is another sea slug which Glides along slowly on its single foot but not all sea slugs move so slowly hermesanwa twists and turns much more quickly the large Pearl gray foot underneath is very flexible the outline of hermesenda's foot is clearly visible as he Glides smoothly down a piece of sea lettuce jellyfish are fascinating animals the underside is hollow and fills up with sea water whenever the body is relaxed whenever the jellyfish partly closes its body most of the water is forced out moving the jellyfish a short distance he is using jet propulsion this action is something like that of a jet plane but it uses gases instead of water this strange jellyfish looks a little like a table lamp pumping itself along some kinds of jellyfish can move much more swiftly the tentacles used for catching food trail along behind if this bright orange fellow is slowed down with a high-speed camera one can see more clearly how he swims the shallow sea Waters of our coasts contain a host of different kinds of worms the sand worm rests briefly between bursts of intense activity by relaxing its long body and drifting slowly downward the sand worm belongs to the same group of animals as our common Garden earthworm like the earthworm its body is divided into many sections or joints each section has a pair of flats with Tufts of yellow silky bristles these are used in swimming when the sand worm throws its body into tight flowing curves resembling the ripples of a silken ribbon in a strong Breeze almost at once it swings again into its dazzling incomparable dance the filtered sunlight shining through its Lacy filigree