Introduction
In zoology, animals group into certain classes or families according to their characteristics. As for the crocodile, groupings land crocodiles in a biological faction and family, Crocodylidae. Nevertheless, some scientists classify crocodiles in a subfamily called Crocodylinae. Sometimes, animal species from the order Crocodilia (alligators, caimans, gharials and true crocodiles) can loosely assume this family under certain circumstances. The family Crocodylidae comprises of reptile species spread all over the tropics in Asia, America, Australia and Africa. These species cohabit in fresh water bodies like lakes and rivers. Crocodiles like any other species of this family, feed on both vertebrates and invertebrates like mammals, mollusks, fish, crustaceans and other reptiles. However, feeding habits depends on the species of the crocodile. Biological experts believe that, before crocodiles, dinosaurs existed and that, there has been little evolutional change. According to evolution theory, crocodiles are 200 million years old having survived massive extinction events that took place long time ago. (Grigg and Gordon 326-333).
Description of Crocodiles
Notwithstanding the prehistoric glance of crocodiles, these reptiles are biologically complex species. For example, crocodiles characterize with a cerebral cortex, a decisive four-chambered heart that function like a diaphragm through muscle amalgamation. This is important especially when crocodiles move from aquatic environment to the one where respiration is paramount. On the other hand, the external morphology of crocodiles put on display, its aquatic and rapacious routine. For example, its muscular nature provides a psyche of an excellent predator pending the aerodynamic body. (The American Crocodile 1-6).
When swimming, crocodiles truck their webbed feet sideways to reduce water resistance hence, faster swimming. Additionally, the webbed feet allow crocodiles to make impulsive moves within water bodies especially when sensing danger or catching a prey. They have characteristic webbed so imperative when these species perform physical walking in superficial water catchments. In order to prevent entry of water, crocodiles possess a rigid tissue just behind the mouth, palatal flap. The palate characterizes with a hollow alleyway detouring the maw from the nostril to the glottis. Interestingly, any kind of submergence will see nostrils close up to prevent water entry. (Uriona and Farmer 1141-1147).
Crocodiles have a bony braincase, which prevent brain crash in case they hit rocks. Nonetheless, unlike other reptiles and mammals, its brain walls do not have postfrontal and supratemporal frames. Ironically, crocodiles cannot move their tongues in and out of the mouth. This is because; a special membrane holds it tightly in place hence; curtailing further movements. The sensory pores in the crocodile scales produce a secretory oily substance paramount in mud flushing during locomotion. (Huchzermeyer 12-13).
In order to crash the prey, crocodiles have very sharp teeth and powerful muscles for holding the prey tightly within the jaws. So far, research indicates that, the crocodile is an animal with the strongest bite, 340 atmospheres.
Biology and Behavior
It is so much amazing to note that, crocodiles feed by hunting. Nevertheless, crocodiles can only rum faster at short distances. This means, crocodiles must be waylay hunters to entice the prey to come close before any attack. Nevertheless, crocodiles are cold-blooded mammals that can go over long period of time without food. The cold-blooded characteristic trait allows low metabolism rate to take place hence; crocodiles can survive quite long without food. A crocodile can sometimes swallow the whole prey, which takes time to digest. In this case, some large crocodiles opt to gulp down gastroliths, stomach stones, in order to provide a digestive environment just like grit in birds. Astonishingly, crocodiles like bigger mammals produce lethargic sounds when they are either distressed or aggressive. They can sense their prey from a distance and listen to peculiar happenings. This is because; they have a special tympanic membrane masked by flat flaps. Depending on the environment they find themselves, crocodiles raise or lower their muscles to position the tympanic membrane in case of any aggression. (Briton, 1-9).
Today, many countries rear crocodile species. Some countries have gone ahead to farm crocodiles for commercial purposes. This is because; crocodile skin is an important raw material for making shoes and handbags. Nevertheless, a great population round the world considers crocodile meat flimsiness hence, not healthy for consumption. There is a wide range of crocodile species. For example, many people who rear crocodiles for commercial purposes opt for Saltwater or Nile crocodiles and in rare circumstances, farmers from the Asian continent rear Siamese crocodiles. (National Geographic 1-5).
Life Cycle of Crocodiles
The life cycle of crocodiles involves mating between the female and male crocodile. Subsequent to mating, the female crocodile lays the fertilized eggs at the riverbank where she made a nest. In a nest of 20-80 eggs, the female nest takes care of the fertilized eggs by putting vegetation and other green plants on it aimed at providing warmth and moisture. There are other predators like fish and sea reptiles, which might invade the eggs hence; forcing the mother to keep an eye. When hatching, crocodile babies will produce sound to alert their mother who will then unseal the nest to take out the hatched babies into freshwater areas in order to feed. Nevertheless, biological research does indicate that, about half of the hatched crocodile babies die without reaching the second year after hatching. Additionally, biological research indicates that, there are no sex chromosomes in crocodile embryos. Unlike in human beings where the genetic make up determine human sex, temperature determines the sex of crocodiles. Independent on room temperature, male crocodiles can only produce at a temperature believed to be 31.6 degrees centigrade. On the other hand, female crocodile production is liberal in that, production temperature can be slightly lower or slightly higher that of male production. (Sydenham, 5).
Crocodile Speed
The speed of a crocodile on land depends on its species. For example, measured through galloping, the crocodile can cover a distance of 17 kilometers within an hour. The crocodile gallop in a snake-like manner by splaying its limbs sideways and whipping its tail from one side to another to give a perfect walking balance. The speed can increase when crocodiles belly run under muddy areas. Other than ‘belly running’, crocodiles can do ‘high walking’ on land by hoisting their head distantly from the soil. Loss of heat in crocodiles occurs through the mouth due to absence of sweat glands. (Anitai 1-8).
Size of a Crocodile
The size of a crocodile depends on its ancient species. For example, dwarf crocodiles (3.3-4.9 ft) are the smallest in size while saltwater crocodiles (15.9ft) form the biggest species in terms of size and weigh over 1,200 kilograms. Sexual dimorphism exhibits in crocodiles where, the male crocodiles possess large bodies and grow faster than their female counterparts. Largest crocodiles can be found in Thailand, United States, and in some African countries. (Anitai, 4-13).
Age of Crocodiles
So far, there is no scientific way of measuring a crocodile’s age. However, scientists have used convincing techniques to estimate the age of crocodiles. As the crocodile grows, it develops lamellar growth rings. A single lamellar growth ring takes an equivalent of one year to develop. Under this technique, a single lamellar growth ring takes one year of dry and wet seasons to build. Albeit small inaccuracies, the average lifespan of a crocodile is 70years although some can even exceed 100 years. (Somma 1-6).
Crocodile Skin
Although covered by scales, crocodiles have a smooth skin characterized by osteoderms, covering the lower and upper part of their body. The scales provide a protective sheath against scorching sun, hurting objects and sometimes, a predatory tactic. Nevertheless, through capillaries that join the rugged armor layer from the skin, it is easier to note how a crocodile absorbs heat. (Richford and Mead 252-253)
Conclusion
The life of a crocodile revolves around hunting. In fact, large species pose great danger to human beings and other mammals. In Africa and Asia, dangerous crocodiles like Saltwater and Nile continue to kill people in great numbers. Less dangerous crocodile species like American alligators harass human beings without serious injuries. Nevertheless, crocodiles are also important economically in that, crocodile skin is an excellent raw material in leather industries for making commodities like purses, wallets, handbags, shoes, and belts. Additionally, some nationalities from Ethiopia, Australia, and Thailand consume crocodile meat. Overall, crocodiles form one of the dangerous reptile species both to human beings, mammals and reptiles.
Works Cited
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Huchzermeyer, Fritz. Crocodiles: Biology, Husbandry and Diseases.2003. Web.
National Geographic. Saltwater Crocodile Profile, Facts, Information, Photos, Pictures, Sounds, Habitats, Reports, and News. 2010. Web.
Richford, Andrew and Mead, Christopher. Pratincoles and Coursers. New York: Firefly Books.2003. Print.
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Uriona, Till and Farmer, Christopher. Recruitment of the diaphragmaticus, ischiopubis and other respiratory muscles to control pitch and roll in the American alligator (Alligator mississippiensis). Journal of Experimental Biology 211, 2008, 1141-1147.