Like cats, crocodiles spit hairballs. However, cats spit out their own hair, while crocodiles may spit out hair from animals such as wild boars, poultry, kangaroos, and even some of them are human hair.
鳄鱼毛球。 图片来源：NQ Dry Tropics NRM
After a full meal, crocodiles can easily digest the meat and bones of their prey, because they secrete stomach acid very quickly, and stomach acid is very acidic. However, the hair of some prey animals is difficult to digest because the hair is made up of strong, non-soluble keratin. Although crocodiles also eat stones to grind food to improve digestion, there are still some hairs that accumulate in its stomach and form a ball of hair, which eventually vomits out.
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In Queensland, Australia, Mark Norman, who has been a crocodile safari guide on a river for decades, has only seen crocodile hairballs in a display case before, and he's always wanted to find one for himself. The hard work paid off, and after a long period of tracking a 4.5-meter-long male crocodile, he finally witnessed the crocodile coughing up several fluffy black balls on the riverbank.
图片来源：Mark Norman
Norman found that the crocodile had also coughed up two plastic coffee bottles. "When I looked closely, the bottle was full of pig hair". And just a few days ago, the crocodile was found to have eaten a wild boar.
图片来源：Mark Norman
In Papua New Guinea, across the sea from the Australian state of Queensland, a similar hairball was found and sent to the university for testing. The test results showed that the hair inside the hairball came from wild boars, kangaroos, wild dogs, possums, flying foxes (Australia's largest bats...... and Caucasian and Melanesian hair.
John Lever, who picked up the hairball, said it was like a list of foods that crocodiles have eaten over the past few decades. "This crocodile has been around for quite some time...... And as an opportunistic predator, it has also eaten several people. ”
In Queensland, Lever actually owns a crocodile farm, but there are no crocodile hairballs because the crocodiles on the farm have a short lifespan and the wild boars they eat are skinned. "Our crocodiles are caught when they reach the age of three or four, so they don't have time to accumulate a lot of hair," Leaf said.
A hairball found inside a crocodile that was killed by a car. Image credit: Dave Edwards
In addition to the complex and diverse composition of the hair, the size of the crocodile hair bulb also varies. Marc McConnell, who works with drought, initially saw a hair ball on the ground and thought it was the carcass of a small mammal, only to discover that it was a crocodile hairball made of wild boar and kangaroo hairs tightly intertwined. The furball he picked up was about the size of a softball. And in Kakadu, Australia's Northern Territory, a furball the size of a football was found in the decomposing carcass of a crocodile.
The texture of the crocodile hairball is also interesting. "You can throw it at the wall, catch it, and it will still stick together. McConnell said. Some crocodile hairballs are hard, and some discoverers have tried to cut them with knives, but the knives have bounced off. The Queensland Museum has a very smooth crocodile hairball that looks like a sourdough bread from a distance.
Andrew Amey, head of the Queensland Museum's collection of amphibians, reptiles and reptiles, believes the difference in texture may be due to the fact that the hairballs have been in the digestive tract for different periods of time, smoother hairballs may have stayed in the crocodile's stomach longer, and the prey fur is ground smooth.
Crocodile hairballs come in different sizes, colors, shapes, and textures. Image credit: Queensland Museum
Adam Rosenblatt, an ecologist who focuses on apex predators such as crocodiles, said that crocodiles do ruminate things that they eat but can't digest. And they don't just spit out tightly packed hairballs. A study tracked 140 baby crocodiles wearing radio collars, and 23 crocodiles were eaten by other crocodiles during the study.
"Eventually radio collars were found lying on the ground, some of them covered in hair and tooth marks. Rosenblatt said. He examined the stomach contents of many crocodiles, and although he himself never found hairballs inside or outside the crocodile, when he lavaged a crocodile, he found that the crocodile that had eaten a dead horse had a large amount of horse hair in the stomach.
图片来源：Mark Norman
Brian Coulter, former head of the Australian Zoo's International Crocodile Rescue Team, noted that saltwater crocodiles are more likely to cough up hair balls because they tend to feed on larger prey such as mammals. The saltwater crocodile is the largest reptile in the world today, with adult males reaching up to 6 meters in length.
Saltwater crocodiles have sharp nail-like teeth and a strong bite that allows them to bite their prey with ease. Crocodiles ambush most of their prey, small ones are swallowed whole, and larger animals are dragged into deep water to drown. Through the "death roll", the crocodile is able to twist the large prey into several large pieces, or tear it to pieces.
A 4.7-metre saltwater crocodile, estimated to be 60 years old, took 8 years for the Australian Wildlife Service to capture. Image courtesy of AFP
Humans are also potential prey for these massive hunters. There are about 30,000 crocodiles in Queensland, and in addition to saltwater crocodiles, there are also smaller freshwater crocodiles (which tend to only attack humans if they feel threatened). Queensland authorities often warn people to be on the lookout for crocodiles, even in a freshwater creek without warning signs, saltwater crocodiles can appear. Although they prefer saltwater environments, they can also survive in freshwater environments. Most crocodile attacks occur to swimmers, canoeing, or people bending over at the water's edge.
In April last year, a 65-year-old man in Queensland went missing while fishing. During the search operation, the police found two crocodiles with a length of 4.1 meters and 2.8 meters near the place of disappearance. Through a follow-up investigation, they found the remains of the missing man in the stomach of the crocodile.
Australia's Northern Territory has more saltwater crocodiles, with an average density of 5.3 crocodiles per kilometre, three times that of Queensland. Image credit: animalspot
Although human hair has also been detected in crocodile hairballs, the most commonly cited source of hair is by far the wild boar. In Australia, wild boars are a devastating invasive alien species. The study found that over the past half-century, saltwater crocodiles' fish-based diet has slowly added more terrestrial animals, including wild boars.
If you look at it this way, those crocodile hairballs full of pig hair can be said to be the crystallization of crocodiles protecting the local ecological environment?
图片来源：VM Reptile Story
bibliography
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[2] Of course everybody wonders what a crocodile hairball looks like! Or do they? (2021, June 25). Retrieved from https://blog.qm.qld.gov.au/2021/06/11/of-course-everybody-wonders-what-a-crocodile-hairball-looks-like-or-do-they
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[5] Dawson, B. (2023). Australia: Remains of missing man found in the stomach of crocodile. Business Insider. Retrieved from https://www.businessinsider.com/australia-remains-of-missing-man-found-in-the-stomach-of-crocodile-2023-5
[6] Fiorillo, C. (2020). Giant crocodile sends helpless pig flying through the air before ripping it in HALF in brutal ambush... Sun. Retrieved from https://www.thesun.co.uk/news/12247900/crocodile-devours-feral-pig-darwin-australia
[7] Ritchie, E. (2024, April 18). Crocs love feral pigs and quolls have a taste for rabbit – but it doesn’t solve the invasive species problem. Retrieved from https://theconversation.com/crocs-love-feral-pigs-and-quolls-have-a-taste-for-rabbit-but-it-doesnt-solve-the-invasive-species-problem-211904
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