The Crocodylus porosus or Saltwater Crocodile is not only the largest species of crocodile but the largest living reptile in the world. Despite being classified as “reptiles”, crocodiles (and all crocodilians, including alligators) are more closely related to dinosaurs and birds (avian dinosaurs) than to most animals classified as reptiles.
Crocodiles have remained virtually unchanged for the last 80 million years, demonstrating the success of their evolutionary adaptations, including their reproductive strategy. One such adaptation is their use of temperature-dependent sex determination - a mechanism that uses incubation temperatures to determine the sex of the developing embryos with low temperatures producing mainly females, and higher temperatures mainly males.
The female crocodiles begin searching for appropriate nest sites shortly after breeding, making mounds of vegetation or digging shallow pits; sometimes they locate their nests in shady places. The amount of eggs laid depends on the size of the female, a large animal lays up to 90 eggs at a time. Once the eggs are in place the mother returns to the water but remains close to protect the eggs for about three months of incubation time. She is very attentive!
The Saltwater Crocodile is sexually dimorphic (sexes are physically different); adult males are on average 5 m long and weigh more than 450 kg, whereas females are much smaller, generally around 3 m long and up to 150 kg. There are unconfirmed records of male Saltwater Crocodiles reaching more than 6 m in length and over 1000 kg in weight. They are long, heavily armoured animals. The Saltwater Crocodile’s eyes, nose and ears are all positioned on the top of its head. This means it can stay underwater with only the top of its head showing.
Despite their name, Saltwater Crocodiles may inhabit fresh- or saltwater but is most commonly found in the brackish estuary areas of Northern Australia in deep, dark murky water. Being a territorial species, larger males will force the smaller crocodiles away from their area. They are capable of swimming long distances and have been found far out at sea. The “Saltie” (so called by Australians) is an ambush hunter remaining hidden under the water until its victim is very close. It will then ‘explode’ out of the water to get it’s pray giving it little chance to escape with the incredibly strong jaws and bite force. Smaller animals are swallowed whole, larger pray dragged underwater performing it’s famous ‘death roll’.
“The ‘death roll’ is a maneuver performed by crocodiles on their prey. It involves the croc gripping another animal in its jaws, dragging it into the water, then rotating, using its body weight to turn over and over, still holding its prey.” (www.quora.com)
Lesser-known Facts & Mythbusting:
Can a human outrun a crocodile? Most crocodiles can achieve speeds of around 12 to 14 kph for markedly short periods, which is somewhat slower than a fit human can run. Don't believe the hype - if you're reasonably fit, you can definitely outrun a crocodile!
(crocodilian.com/cnhc/cbd-faq-q4.htm)
Crocodiles do not die (like most species do). Although the crocodiles can't die of natural aging, they also can't live forever. Nature has a way of killing them. The way they die is out of starvation or if they contract a disease or - of course - human interference. They keep growing throughout their lifespan. (awesci.com/crocodiles-do-not-die/)
“Cassius is a male saltwater crocodile (Crocodylus porosus) recognized by the Guinness World Records as the world's largest crocodile in captivity in 2011. The animal measures 5.48 m in length, weighs approximately 998 kg and is estimated to be more than 110 years old.”
How long can they hold their breath? Usually they can hold their breath from 4 - 15 minutes but can remain underwater for two hours if needed and if they aren't stressed. The record time spent underwater is eight hours in freezing conditions; this is because a cold crocodile uses less energy and oxygen so it can hold its breath longer than a warm one. (https://www.vanaqua.org/learn/aquafacts/reptiles/crocodilians)
“Since 1971, Australia has witnessed 99 attacks on people by saltwater crocodiles, of which 27% were fatal. On average that's around 2.3 attacks per year over four decades, of which 0.6 were fatal.”(theconversation.com/croc-attacks-a-new-website-with-bite-20671)
Most crocodile attacks occur between late September and January when crocodiles are hungry after the dry season and are preparing to breed. Most victims had been under the influence of alcohol, swimming at times in the murky water and in places that most sensible people would avoid.
On average only one person a year is killed by a crocodile attack in Australia - in comparison three people a year die from bee stings and thousands from smoking and car accidents. In 2016 alone, four people died falling from chairs!
(https://www.dailytelegraph.com.au/news/nsw/most-unusual-causes-of-death-in-australia/news-story/a8a3ffb30d802f0e49759bf128aa12de)
The key point is that with some sensible precaution taken, observing the warning signs and importantly common sense we can live in harmony with these amazing creatures from prehistoric times - their existence dating back to the “Cretaceous Period”.
All deaths are tragic, but please don’t believe the handful of backward, fact-challenged politicians looking to score political points
from what is essentially a non-issue.
🐊
REFERENCES
Australian Government - Department of Environment and Energy, 2018 (viewed 27.04.2018)
Wildscreen Arkive (viewed 28.04.2018)
Pets on mom.me, 2017 (viewed 27.04.2018)
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