Crocodiles lived through the Cretaceous era when the dinosaurs disappeared, survived the breakup of the ancient world when continents split and drifted across the globe and they even made it through the Ice Ages of the last two million years. Crocodiles live in tropical climates near freshwater habitats such as lakes, rivers, wetlands and sometimes brackish water, which is saltier than freshwater, but not as salty as the sea.
However, saltwater crocodiles of Southeast Asia, Australia and the Pacific islands often live in coastal areas. The social behaviour of crocodiles is difficult to study in the wild, so knowledge about this is limited. They also have a hierarchy, where the highest ranked gets to choose the best sunning and shade spaces. Their mating season is between January and May and sexual maturity is linked to the length of the animal. Males attract females by slapping their snouts in the water, bellowing, using various other vocalisations and blowing water out of their noses.
Vigilant and dedicated, crocodiles make excellent mothers and many will use the same nesting site year after year. Mothers remain close to the nest throughout the incubation period, actively defending it when necessary.
For the eggs to hatch, they must be kept at a temperature of between 27 and 34 degrees — the temperature also determines the sex of the hatchlings. Although crocodiles rarely move away from water, their eggs are laid in an underground nest on dry land. After laying, the female will seal the nest to secure it from predators and keep vigil for the next 90 days. When the eggs hatch below ground, the young call for their mother who is on stand-by waiting to dig them out.
From here she will transport them to a nursery pool where they will immediately put into practice their innate hunting instincts. Creches are formed and although the mothers may stay around for several months, one female will sometimes take on the responsibility of looking after a hundred or so hatchlings.
Some species stay with their young for up to three years. Crocodiles are carnivores and eat birds, fish, crustaceans, mammals and frogs. Big species such as the Nile Crocodile can bring down animals as big as buffalos and zebras. As ambush hunters, they wait for their prey to come close and then lunge forward to attack.
They clamp down their jaws on the prey, crush it and then swallow it whole. Crocodiles cannot chew their food and so swallow small stones to help them digest it by grinding up the contents of their stomachs. They have a very slow metabolism and can survive for months without food. Crocodiles live on average between 50 and 75 years, depending on the species.
The oldest crocodile in captivity reached the age of around years. He was called Mr Freshi, a freshwater crocodile, and lived in an Australian zoo. Hatchlings and young crocodiles have a wide range of predators, including birds such as herons, egrets and eagles, large fishes, turtles, bobcats, black bears and other crocodiles.
As they grow bigger, the risk of being eaten by another animal decreases while the risk of being killed by humans increases. The most endangered of the species is the Cuban crocodile which, mainly due to poaching, now has a population of only 4, Predators of adult crocodiles, ironically, are other adult crocodiles if food sources are scarce, but also big sharks and big cats such as jaguars and leopards will hunt them, and sometimes huge snakes such as anacondas and pythons.
Best Management Practices for Crocodilian Farming. The sale of their skins is more profitable than their meat; which is seen as a by-product. Due to poaching and habitat destruction, the wild crocodile population declined in the s and s and it was this that led to crocodile farms gaining popularity.
With the flourishing demand of the crocodile skin trade in the s and s, many species, including the Australian saltwater crocodile Crocodylus porosus were hunted to the brink of extinction. It is estimated that between , and , Australian saltwater crocodiles were killed between and — 45, of which were hatchlings, destined for the curio trade.
Today, there are 13 crocodile farms in Australia alone and the majority of skins and meat are exported. Live crocodiles are captured and removed from their natural habitat and it is perfectly legal as long as the animals are taken in accordance with a management programme.
Crocodiles are not widely farmed in the UK but in , a farmer from Cambridge made headlines as the first person in the country to farm them.
Crocodile meat for Fenland farm. The farmer uses fallen chickens and pigs and other animal waste from intensive factory farms as food for the animals, who are slaughtered and sold commercially. Thailand is the world leader in crocodile farming, with around one million animals on 20 mega farms and around 1, farms in total.
The biggest farm has around , animals 5 Reuters, One of these huge farms is only a two hour drive from Bangkok.
After 45 days the eggs start to hatch, with the big farms hatching around 20, baby crocodiles each year. While crocodile farming is growing around the world, there have never been so few in the wild and they have now been listed as an endangered species. On crocodile farms, animals live in small enclosures crammed in with dozens of others. There may be a water pool for swimming but the overcrowding ensures that only the highest ranking crocodiles will get to fulfil their natural need for water.
Farmed crocodiles may look calm and content but the practised eye of a reptile scientist can see the signs of severe distress which the animals display and have to endure for several years until they reach slaughter age. But many locals illegally enter the forest areas to collect honey, wood, fish and crab. The department has erected barricades on the banks of about 50 ponds and rivers in the park and its nearby areas to prevent the crocodiles from attacking human beings. The exact number of crocodile attacks is unavailable in the forest department.
But locals believe that at least six to ten persons are killed or maimed by crocodiles each year. In , the ministry of forest and environment, in collaboration with the United Nations Development Programme, had started a crocodile breeding and rearing project in Dangamala within the Bhitarkanika Nationa Park.
Between then and now there have been 33 crocodile attacks in Queensland, 11 of them fatal. The department's data shows there has been one attack every year over the year period, and one death every three years. While this is nowhere near Mr Katter's claim of a person being torn to pieces every three months, the data does show an increase in the rate of both attacks and fatalities over recent years.
According to the register there were 16 attacks in Queensland in the 20 years from to , four of them fatal. The statistics do not support Mr Katter's claim, whatever time period is selected.
The rate of crocodile attacks over the past decade is one every 10 months, and the rate of fatalities is one every 20 months. Looking at the figures from the past five years, the rates are the same. Over the past three years, the rate of attacks is one every six months, and the rate of fatalities is one every year. In there have been three attacks, two of them fatal. These most recent fatal attacks occurred seven months apart, in March and October.
In a statement, a spokesperson for the ABS told Fact Check that according to its Causes of Death data there were nine crocodile attack deaths in Queensland between and This is the same number as shown on the department's register for that period. The register's total of 11 deaths since includes two deaths in A research paper published by the CSIRO, Patterns of human-crocodile conflict in Queensland: a review of historical estuarine crocodile management , contains earlier figures.
The paper, whose authors include four staff from the Queensland Department of Environment and Heritage Protection, said estuarine crocodile attacks on humans non-fatal and fatal have been reliably recorded by the State Government since It found that between and , there were 35 recorded crocodile attacks, 12 of which were fatal.
While confirming that attacks have risen in recent years, the paper said a far greater proportion of attacks were fatal between and than between and The department's figures show that since , there have been a further four attacks, three of them fatal, giving a total of 39 attacks and 15 fatalities since , at a rate of an attack every 14 months and a death every three years. A non-fatal attack occurred at Cape Tribulation in far north Queensland on November 28, Fact Check assesses claims based on information available at the time the claim is made, and as this attack happened after Mr Katter's claim it has not been taken into account.
According to the CSIRO paper, the human populations of the two largest cities in north Queensland, Townsville and Cairns, increased by 25 per cent between and The report also noted the population of estuarine crocodiles in Queensland had increased since becoming protected in , though experts told Fact Check there had been limited crocodile population surveys for a number of years.
The CSIRO researchers found increasing human and crocodile populations in the Northern Territory to be related to an increase in attacks. The Queensland Department of Environment and Heritage Protection also commented on the issue of population changes when it made a submission to a parliamentary inquiry into the May Safer Waterways Bill introduced by Katter's Australian Party.
Crocodiles do not necessarily set out to hunt humans, but they are opportunistic killers. In Africa alone there are several hundred crocodile attacks on humans per year, between a third to half of which are fatal, depending on the species.
Many take place in small communities and are not widely reported. Worldwide, crocodiles are estimated to kill about 1, humans per year, many more than sharks. Alligators, which only occur in the wild in the US and China, are less aggressive than crocodiles but can still be dangerous.
In the US state of Florida, 22 people have been killed by alligators since , the state authorities say. Read more: Why do crocodiles attack humans? Ungainly as it is, the hippopotamus is the world's deadliest large land mammal, killing an estimated people per year in Africa.
Hippos are aggressive creatures, and they have very sharp teeth. And you would not want to get stuck under one; at up to 2,kg they can crush a human to death. The beautiful creatures with a deadly streak. The slow and deadly dzud in Mongolia. The amazing science behind fatal snake bites. Image source, AFP.
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