Saltwater Crocodile Adaptations PDF

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Saltwater Crocodile Adaptations...

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Saltwater Crocodile Adaptations Having developed an incredibly successful suite of adaptations, crocodilians have remained relatively unchanged over the last 200 million years. Saltwater crocodiles (Crocodylus porosus) are the largest of 23 living species and function as apex predators in the ecosystems in which they live. Crocodilians use several common aquatic adaptations to thrive in these habitats; however, it's their unique adaptations, including impressive jaws and integumentary skin organs, that have allowed them to dominate their habitats for so long. Aquatic Adaptations Saltwater crocodiles are not the only animals that have adapted to a semi-aquatic existence; animals from a variety of lineages exhibit similar adaptations. For example, just as crocodiles have webbed feet that help them to swim, animals as diverse as beavers, ducks and frogs also possess and use webbed feet. The eyes and nostrils of many aquatic animals -- including snakes, frogs and turtles -- are on the dorsal, rather than lateral, surface of the head, just as they are in crocodiles. Finally, just as sea snakes, aquatic lizards and fish have laterally flattened bodies or tails, crocodiles use their flattened tails to propel themselves through the water. Sealing the Seams When diving underwater, crocodiles seal most of their body’s orifices to keep the water out. Crocodiles have muscular flaps that help them to close their ears and nostrils. Additionally, crocodiles and alligators have a cartilaginous flap attached to the back of the tongue. This flap functions to keep water from entering the animal's lungs or stomach when the mouth is open underwater. With this flap, crocodiles can capture prey while in or under the water. Jaws of Life The jaws and teeth of saltwater crocodiles are essential to the survival of the species. Adapted for grasping and crushing prey, crocodiles capture animals as large as buffalos. Equipped with 64 to 68, 3.5-inch-long teeth, few animals escape from the jaws of saltwater crocodiles. Professor Greg Erickson and his colleagues at Florida State University studied the jaw pressure of crocodiles and found that, while most crocodilians were capable of generating largely similar bite forces, the saltwater crocodile generated the strongest bite. The results of the 11-year study, published in a 2012 issue of "PLoS One," show the bite force of these animals to be approximately 3,700 pounds per square inch -- the strongest bite force ever measured. Integument Intel Crocodiles have a number of small skin organs -- called integumentary sensory organs, or ISOs -- on and just behind, their heads. These organs are sensitive to mechanical, thermal and pH stimuli, providing the crocodile with a huge amount of information from a few small receptors. The ability to detect the amount of salt in their water varies among the species of crocodiles.

Gladiator Goggles The eyes of crocodiles are exposed to a variety of threats, including struggling prey and submerged sticks and rocks. To protect their eyes, crocodilians possess a third set of eyelids termed nictitating membranes. The nictitating membranes cover the eyes of crocodiles when they dive underwater and are somewhat transparent. While crocodiles cannot see well when their nictitating membranes are closed, they can distinguish light from dark. More than 200 million years ago, crocodiles roamed the Earth among the dinosaurs, and their skulls alone measured approximately six feet in length. Today’s crocodile began evolving 80 million years ago, developing the traits that have enabled its survival. While body armor of bony plates comes to mind, this rough and tough exterior is only the beginning. A combination of physiological and behavioral adaptations has ensured the crocodile’s survival through the ages. This Temperature is Just Right As the largest members of the reptile world, crocodiles are cold-blooded. They are ectotherms, meaning that they must seek out warmth to maintain their body temperature. Crocodiles can be found sunbathing when climate temperature is too cool, and basking in rivers when they become too warm. Crocodiles are able to regulate their own metabolic rate merely by engaging in these warming and cooling practices. When ideal body temperature is maintained, their metabolism slows to the point where food is not a daily requirement for survival. Crocodiles have the ability to forgo a meal for months at a time as most of their food intake is efficiently metabolized and stored, conserving the crocodile's energy for other purposes. A Cast-Iron Stomach On average, a crocodile dines on 50 feasts per year. Crocodiles have extremely indiscriminate palates, and so their digestive system has adapted to process anything they consume, from crustaceans, mollusks and fish to birds and mammals. The acid level in their gastric secretions is the highest of all vertebrates. As bones, hooves, horns, shells and other solid materials get broken down, these rock-like items aid in grinding down coarse food. No matter what the crocodile chooses off the menu, none of it goes to waste. The Brain of a Crocodile With the most highly developed and complex brains of all reptiles, crocodiles possess keen awareness and a strong learning ability. Their heightened auditory and olfactory senses forewarn them of dangers and guide them toward prey. To enhance their underwater visual capacity, a protective membrane covers their eye. The iris of their eye achieves optimal night vision. They learn to avoid repeated threatening situations by navigating new routes after a single perilous encounter. This has thwarted numerous attempts of their capture by human beings. No Match for Man Crocodiles are a living link to the dinosaur age, and their survival has come so far. Despite the crocodile’s adaptations for surviving through millions of years, the U.S. Fish and Wildlife Service now lists the American crocodile as an endangered species. Their critical population reduction is the result of illegal poaching and habitat depletion by man’s encroachment on

their turf. Enforcement of laws against hunting, environmental awareness education and habitat expansion are steps that are currently underway to preserve the crocodile for millions of years more. Due to the fact that members of the crocodylidae family have been in existence for over 55 million years, they have been able to adapt adequately in many different environments. One of the more unique features that members of the crocodilians have is the location of the eyes, nostrils, and ears on the head. All three of these are located towards the top of the head, which allows these organisms to completely submerge in water and still be able to see, breathe, and hear by only exposing the top part of their head. Another feature crocodiles possess, which is also seen in the alligators, is the ability to regulate body temperature by lying with its mouth open. On sunny days, crocodiles can be seen basking in the sun which on its own is a method of regulating body temperature, but they also open their mouths in a behavior called “gaping”. Both of these actions help allow the animal to keep a stable 77° F internal body temperature. It has also been speculated that these animals keep their mouths open to reduce the risk of a fungal infection by allowing the mouth to dry out. Basking also aids in digestion for crocodiles as it helps increase the metabolic rate as opposed to when the animal is in colder conditions the metabolic rate is slowed. Finally, the presence of a transparent eyelid allows crocodiles to go underwater and still be able to see very well. This is a huge advantage to these animals because they use stalking and stealth as primary means of hunting. Crocodiles also have a vertically shaped pupil that allows for extremely good night vision in these organisms. While these creatures have been evolving over the years, they have also developed a wide range of prey by which they acquire their Nutrition.

References: https://animals.mom.com/encounter-crocodile-2450.html https://animals.mom.com/top-swim-speed-crocodiles-7293.html http://bioweb.uwlax.edu/bio203/s2012/shirley_josh/adaptation.htm...