Saltwater Crocodile
by Luke Harvell
Description and Rationale
The Saltwater Crocodile, also known as the Crocodylus porosus, lives in most parts of Southeast Asia and Australia. It is the largest species of crocodile, with some recorded around 25-27 feet long; females being smaller than males. When Saltwater Crocodiles are still young, their skin is a pale tan color but as they mature the skin color begins to go darker. At one point, the Saltwater Crocodile was nearly extinct in the 1970’s but laws were made by the Australian Government, and later on by the Philippine Government and several other countries, protecting them. Now there are around 200,000 to 300,000 crocodiles in the wild today.
What is so important about the Saltwater Crocodile and how does it affect the ecology of the Philippines? Is its skin in such demand that people are hunting and killing these animals to make shoes and other everyday items? Are their teeth such a popular accessory that people hunt them for a simple necklace? What can we do to save the crocodiles from going back into that state of near extinction?
Can we find new uses for the crocodile other than killing them for their skins? Even with a law restricting poaching of these animals in the Philippines, could we create a task force or patrol unit that enforced the law? Is there any place in the Philippines where we could create a sanctuary for these crocodiles to live in peace? Could more zoos look after these Saltwater Crocodiles and ensure their safety, while making money from viewing visitors?
The main purpose of this project will be to research the biology and ecology of the Saltwater Crocodile. There will be research done through the use of the Internet and other sources such as books and videos, there will hopefully be interviews with local zoo experts about the Saltwater Crocodile and its habitat. Also, there will be information distributed to the public through brochures to help increase awareness about this species extinction. Hopefully, one of these days, the Saltwater Crocodile will be permanently kept off the endangered species list and once again thrive in parts of the Philippines.
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Biology
Common Names and Synonyms
The Saltwater Crocodile, also known as Crocodylus porosus or as the native Filipino people call it Buwaya. Other names given to the crocodile from around the world include Gatta Kimbula, Gorekeya, Kone huala, Jara Kaenumken, Pita Gatteya, Pukpuk (Aboriginal name), Rawing crocodile, Semmukhan Muthlelei, Sea-going crocodile, Subwater crocodile and Man-eating crocodile.
Classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia (reptile)
Order: Crocodylia (crocodiles; alligators; caimans; gavials.)
Family: Crocodylidae (true crocodile)
Genus: Crocodylus (pebble worm)
Species: C. Porosus (pebble worm masculine)
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Morphology and Physical Description
External Anatomy
The crocodile can grow up to 15-20 feet long, with some reports of crocodiles being anywhere from 25 to 30 feet long. This species has a large head with a heavy set of jaws. Two ridges run from the center of the snout to the eye, these become more distinct with age. The upper surface of the top jaw becomes very wrinkled in large male crocodiles. Unlike other species scales on the flanks are more oval, although belly scales are rectangular, even and small. Osteoderms (bony deposits forming scales, plates or other structures) are only on the back and a small cluster on the neck. Young crocodiles are usually pale tan in colour with black stripes and spots on the body and tail.
Internal Anatomy
Crocodiles do not have a vomeronasal organ (is an auxiliary olfactory sense organ that is found in many animals) except in the embryonic stage or a urinary bladder. Unlike other reptiles, but similar to birds and mammals, crocodiles have a four-chambered heart; but, unlike mammals, oxygenated and deoxygenated bloods are mixed because they have the left aortic arch which makes this possible.
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Getting Food
Young crocodiles can only eat smaller animals such as insects, amphibians, crustaceans, small reptiles and fish. The bigger the animal grows, the greater the variety of animals it includes in the diet, although small prey make up an important part of the diet even in adults. Large adult saltwater crocodiles can eat monkeys, kangaroos, wild boars, dingoes, goannas, birds, domestic livestock, pets, water buffalo, gaurs, sharks, and humans, among other large animals as well. Domestic cattle, horse, water buffalo and gaur, all of which may weigh over a ton, are considered the largest prey that can be eaten by a male crocodiles. The typical crocodile feeding technique is to wait close to the shore of the water and ambush preys that come to close. Larger crocodiles follow or stalk potential prey, but in most cases the animal hides itself until just before the attack. The only threats to adult saltwater crocodiles are other crocodiles and humans. Crocodiles can last a month without food.
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Reproduction
Female crocodiles lay 40 to 60 eggs in mound nests made from vegetation and mud. The mound keep the eggs temperature the same, hides them from predators, keeps them hydrated, and also keeps the eggs off the ground to keep them from flooding. In saltwater crocodiles flooding is the main cause of embryo death, not destruction by predators. Although the mother stays near the nest, eggs do fall prey to predators (e.g. monitor lizards, feral wild pigs in Australia) and human egg collectors. Juveniles normally hatch 80 to 90 days after they are layed but this varies with temperature. When the young crocodiles start chirping and hatch from their shells, the mom carefully helps them down to the water in her mouth. A lot of research has been carried out into TSD (Temperature-dependant Sex Determination) in this species, which is important for captive breeding programs to influence the sex ratio, and to produce faster growing males for farming purposes. The highest percentage of males are produced around 31.6°C, with more females a few degrees above and below this. It is said that less than 1% of hatchlings will survive to reach maturity, due to flooding, predation, competition for resources, and social pressures.
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Environmental Factors
Saltwater crocodiles normally spend the tropical wet season in freshwater swamps and rivers, swimming downstream to estuaries in the dry season, and even travelling far out to sea. Crocodiles compete fiercely with each other for territory, with more mature males living along the best parts of freshwater creeks and streams; their only competitors being bigger crocodiles and humans. Young crocodiles are pushed into the smaller rivers and even into the ocean. This is why some crocodiles have been found swimming from the east coast of India to northern Australia, or even being found in the Japan Sea.
The saltwater crocodile helps keep the balance in the web of life in both freshwater and saltwater ecosystems. Being an apex predator they are the top predators on the food chain, and eat a lot of different types of prey. When young they are also prey to animals like feral pigs, goannas, turtles, barramundi, sea eagles and even other larger crocodiles. Since they are both predator and prey, they give a good balance to the ecosystem. When a wetland habitat is doing well, then the fishery is also doing well.
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Origin and Distribution
The saltwater crocodile spans many different countries including Australia, Bangladesh, Brunei, Myanmar (Burma), Cambodia, China, India, Indonesia, Malaysia, Palau, Papua New Guinea, Philippines, Singapore, Sri Lanka, Solomon Islands, Thailand, Vanuatu, Vietnam. Some crocodiles have been found as far as the Japan Sea or the Indian Ocean, which are more than a thousand kilometres away. Because of this ability they are able to be very wide spread.
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Importance to People
The skin of the saltwater crocodile is very valuable. Many people pay thousands of dollars to own crocodile products, while the saltwater crocodile products are the most valuable. In farms, the crocodile is raised until it is old enough, then it is killed and skinned. Many people do not like this idea, due to the fact that very little of the crocodile is actually used. But in some countries such as Australia, Thailand and the Philippines the meat of the animal is eaten. The meat is white and has high nutritional values, but higher cholesterol levels. Crocodile meat has a unique flavour; people said it to be a mix of chicken and crab. Also the crocodile oil has been used for centuries as a natural healing skin lotion. Crocodile teeth and claws also serve as jewellery or accessories to some of the more rugged people. Uses for the crocodile remains are still being researched and tested yearly. How could we make better use of the full crocodile instead of just killing it for one patch of skin?
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Survivability and Endangered Status
On average, the saltwater crocodile will live up to 70 years with some living as long as 100 years. The saltwater crocodile used to be thriving and wider spread in population, but due to over hunting the population was near extinction during the 1970’s. Seeing a need to intervene, the Australian Government banned hunting of the crocodile, along with many other national governments. Due to this protection, the population of crocodiles jumped from near extinction to around 200,000 to 300,000 in the wild today. That is why the IUCN has it rated at Least Concern. While in the Philippines, due to few to no sightings the animal is rated as At Risk.
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Potential Solutions
The extinction of species is a very real threat to animals all over the world, especially with the rapidly increasing population of humans. It has been estimated that around 137 species go extinct every day, and because of that, the biodiversity of the entire world is being affected. One animal almost extinct is the Saltwater Crocodile, which lives in Southeast Asia and Northern Australia. In the Philippines the endangered level of the species is At Risk, but there seems to be hope on the horizon. Filipinos are beginning to become aware of the problem and some places are even doing something about it. Like in Palawan, Philippines there is a crocodile farm where young crocodiles are rescued and harvested. Below are 3 different possibilities of what can be done to help the Saltwater Crocodile get off the endangered species list, along with the advantages and disadvantages of each possibility.
Possibility 1 - Avilon Zoo
While researching, I remembered the name of a zoo I once visited a few years back. Vaguely I remembered seeing in the zoo a 14 foot Saltwater Crocodile. I looked up the contact information for the zoo and was able to call the office; I planned an appointment with one of the tour guides, Mark Coliseto, who was in charge of the reptiles. On the day that we were scheduled to meet, there was a huge rain storm and he called and said that today would be a bad day because most of the exhibits, including the crocodiles was closed. This put a damper on me collecting information but I was able to talk to him for around 15 minutes on the phone asking him questions.
Advantages:
1. If I could have gone to the zoo I could have seen they way that they are fed or taken care of, instead of just hearing about it.
2. If the tour was good, or full of information and helpful then I could have recommended it to other people who are also curious about the Saltwater Crocodile.
Disadvantages:
1. That Saturday was my only chance to go to Avilon Zoo and due to poor weather conditions that was cancelled, maybe sometime in the future I will visit.
2. He said that the trip for me would take around 1:30 to 2 hours, which would make a round trip 4 hours. You would end up spending a whole day.
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Possibility 2 - A Wildlife Animal Zoo
What better way to ensure the survival of the Saltwater Crocodile then to put them in a zoo. This would ensure breeding, a safe environment and food daily to the animal. No longer would it have to compete for its next meal or be hunted by humans. Also Saltwater Crocodiles are the largest reptile in the world, what better way to attract all kind of audiences to your zoo.
Advantages:
1. Also in the zoo, the crocodile would be such an attraction that zoo keepers could talk to the children about the crocodile, and the importance of taking care of the environment.
2. The crocodile wouldn’t face the risks of living in the wild, lack of food and humans hunting.
3. One of the biggest advantages would be the income that the zoo would make with the Saltwater Crocodile and the other animals. The money could then be used for research, building better environments for the animals, or also increasing the size of the zoo which could also lead to more income.
Disadvantages:
1. One possible problem would be that the Saltwater Crocodile would not adjust or adapt well to its created environment. If this happened the crocodile would not reproduce or eat, this would only hurt the species instead of helping it.
2. The enormous cost of building an entire zoo, bringing in the animals, attracting attention of the public would be incredibly costly. To do all of this would take some sort of outside connections with people who have money, and at this moment I have no such connections.
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Possibility 3 - Create a Brochure to Distribute (action step)
It has been scientifically proven that more people learn visually then any of the other learning styles. I used this to my advantage. Not only would it be attractive and draw the reader’s attention, but they were easy to make and distribute. On the slips of paper I put down the important information along with how an average person could help.
I created 20 brochures, then went around my neighborhood and the neighborhood next to ours and passed them out. A lot of people took the brochure and truly seemed to care, and this being the Philippines, I was invited in to several houses and given meriendas. Overall the response I received from the 20 different houses was good, and this made me feel better about my cause.
Advantages:
1. The fact that I know the native language of Tagalog, this was a great tool in being an icebreaker to some of the houses I visited. Also I had Caleb join me in my adventures to be my photographer. I had Caleb come along because he was young and the people in the houses would not be intimidated or feel threatened.
2. Unlike communication, the further it gets passed on the more mixed up the words become, with a brochure the message can be spread to many all the while the message staying the same. Who knows, some of the house owners may have even passed on the brochure to a friend or another family member.
Disadvantages:
1. Once again money becomes the issue, while it was easy to print off 20 copies to mass produce would take more money and I don’t have that kind of money.
2. The handing out of the brochures was a quite easy, but the real task was getting the people in the houses to listen. Some were more ready to listen then others, while on the other hand some seemed to pay close attention.
POSSIBLE FUTURE DIRECTIONS
While talking to Mark he seemed eager to have more participation from the outside world within the zoo. If my research was to continue in this I would probably meet back up with Mark or have him lead a group of us through the reptile exhibits.
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Bibliography
Britton, Adam. "Crocodylus porosus." Kingsnake.com - the information portal for reptile and amphibian hobbyists. not given. 04 May 2009 http://www.kingsnake.com/oz/crocs/porosus.htm.
Coliseto, John. "The Saltwater Crocodile." Telephone interview.
"Crocodilian Species - Australian Saltwater Crocodile (Crocodylus porosus)." Florida Museum of Natural History. 2003. 04 May 2009 http://www.flmnh.ufl.edu/cnhc/csp_cpor.htm.
"Ecotourism - Puerto Princesa Philippines - Puerto Princesa City Travel Destination Guides, Informations, Travel Tips, Travel Flights, Hotels and Resorts, Recreations and Activites, Travel and Tour Packages." Puerto Princesa Philippines - Ecotourism Capital Of The Philippines - Puerto Princesa City Travel Destination Guides, Informations, Travel Tips, Travel Flights, Hotels and Resorts, Recreations and Activites, Travel and Tour Packages. 2000. DotCom International Marketing. 04 May 2009 http://www.puertoprincesaphilippines.com/ecotourism.html.
"Saltwater Crocodile -." Wikipedia, the free encyclopedia. not given. 04 May 2009 http://en.wikipedia.org/wiki/Saltwater_Crocodile.
"Saltwater Crocodile, Saltwater Crocodile Profile, Facts, Information, Photos, Pictures, Sounds, Habitats, Reports, News - National Geographic." Animals - Facts, Information, Photos, Pictures, Sounds, Habitats, Reports, News - National Geographic. 2008. National Geographic. 04 May 2009 http://animals.nationalgeographic.com/animals/reptiles/saltwater-crocodile.html.
"Saltwater Crocodile:." The Animal Files. not given. 04 May 2009 http://www.theanimalfiles.com/reptiles/crocodiles_alligators/saltwater_crocodile.html
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