The crocodile which attacked a Kiwi woman in north Queensland was almost certainly striking out of hunger, says an Australian crocodile expert.
John Lever has been working with crocodiles for more than 40 years and owns Koorana Crocodile Farm in Coowonga, Queensland.
He told the Herald crocs could be extremely territorial when they were mating or protecting their young, but at this time of year it was highly unlikely this was the reason a crocodile attacked Kiwi expat Cindy Waldron, 46.
"They're very territorial animals, especially when they're producing sexual or parental hormones and that's when they become dangerous to us normally.
"But at this time of the year we couldn't say it was a female defending her young," he said.
"This would be a hunger attack and that's all there is to it."
Cindy Waldron was swimming with her childhood friend, Leeann Mitchell, 47, at Thornton Beach, in the Daintree Rainforest - 112km north of where Ms Mitchell lived at Trinity Beach in Cairns - at about 10pm on Sunday when they felt a nudge.
Then Ms Waldron screamed: "A croc has got me!"
Ms Mitchell tried in vain to drag her friend away. Ms Waldron has not been seen since.
Over the decades Mr Lever had heard of a few people escaping crocodile attacks but, he said, unless the croc was very young most people wouldn't stand a chance once one got hold of them.
"If it's a large crocodile you can kiss the world goodbye."
Crocodiles were extremely sensitive, with their eyes, ears and noses finely attuned to seek out prey.
"Ten percent of their brain is for sense of smell," Mr Lever said.
"Their sense of vibrations, which is what would have been happening in this case, is quite extreme. They can feel vibrations through the land and through the water."
Crocodiles have pits of skin around their teeth which pick up vibrations of nearby prey.
"Even in pitch black night when they can't see anything they can feel when food is close."
Saltwater crocodile facts
1. Male crocodiles are much larger than females. Males can measure up to 7m, and weigh up to 1000kg, while females rarely grow beyond 3m.
2. Their jaws have between 64 to 68 sharp teeth, they are driven by powerful muscles which in a single bite can crush the skull of a cow.
3. The saltwater crocodile or estuarine crocodile (Crocodylus porosus) is the largest reptile existing nowadays, and can be extremely dangerous to humans.
4. Saltwater crocodiles are found all over northern Australia and in many Asian countries as well as on several Pacific islands.
5. Life expectancy is generally accepted to be upwards of 70 years with some crocs living for more than 100 years.
6. Their eyes have a special clear eyelid which protects the eye while they are underwater
7. Female crocodiles typically lay between 40-60 eggs at a time. If the eggs are incubated below 30C they will be female. Above 32C and they will become males.
Freshwater crocodile facts
1. Freshwater crocodiles (Crocodylus johnstoni) are only native to northern Australia. They are found in inland freshwater areas of the Australia including rivers, freshwater wetlands, creeks, lagoons, swamps, and billabongs. However, they can be found in some of the same areas as saltwater crocs as they are somewhat tolerant of saltwater.
2. Male freshwater crocodiles can measure up to 3m in length, however females are much smaller, and rarely grow more than 2m long. It can take 30 years for a crocodile to grow to its full size.
3. Freshwater crocodiles have a lifespan of 50 or more years, with most of their growth occurring in the first 20 years.
4. They are capable of moving at an incredible speed on land reaching up to 17km/h, which they do that by galloping.
5. They are preyed on by saltwater crocodiles.
6. They are a shy species, and aren't considered dangerous to humans, like their bigger relative the saltwater or estuarine crocodile. However they can deliver a very nasty bite, if provoked or disturbed.
7. All the females in a certain area will usually nest within three weeks of each other in the breeding season.
Source: Roberto Lapinski, animal and exhibits manager at Butterfly Creek.