8 Main Differences Between Freshwater and Saltwater Crocodiles
So What's the Difference Between Freshwater and Saltwater Crocodiles?
Often known as "freshies" and "salties" to Australian locals, freshwater and saltwater crocodiles are two species that you may encounter if you travel through Australia. It's useful to know the difference between them, mainly because saltwater crocodiles can be very aggressive and be dangerous to humans and should be avoided at all costs. Freshwater crocodiles are less likely to attack.
Note: Always err on the side of caution. If you think that a crocodile might be a saltwater, based on size, keep well away and don't be tempted to take a closer look.
8 ways to tell freshwater and saltwater crocodiles apart:
- Shape of the snout. Freshwater crocodiles have long, thin snouts, compared with saltwater crocodiles, which have broader, more powerful snouts.
- Location. Freshwater crocodiles only live in northern Australia. Saltwater crocodiles live in a much wider area, stretching all the way from the eastern coast of India and throughout most of Southeast Asia, all the way down to and including northern Australia.
- Habitat. As their names suggest, saltwater crocodiles prefer water that is more saline or salty, whereas freshwater crocodiles prefer a freshwater habitat.
- Jawline and teeth. Freshwater crocodiles have straight jawlines and their teeth and fairly evenly sized. Saltwater crocodiles have uneven jawlines and their teeth vary in size.
- Size. A full-grown saltwater crocodile can easily be 3 meters (10 feet) longer than an adult freshwater crocodile.
- Diet. Freshies tend to eat smaller animals that are found near rivers, such as insects, turtles, fish, frogs, snakes, and waterbirds. Salties also eat small animals, but in addition consume larger prey such as wild pigs, and livestock.
- Armored plates. Freshwater crocodiles have closely-knit armored plates on their back, while saltwater crocodiles do not..
- Behavior. In terms of aggression, the saltwater crocodile is a much bigger threat to humans.
Once you understand the differences, it becomes fairly easy to tell them apart. I explore each of these differences in detail below.
1. Different Shaped Snouts
One of the main differences between freshwater and saltwater crocodiles is the snout. The freshwater's is long and relatively thin, whereas the saltwater’s is thicker and more powerful-looking.
The difference in snout shapes has most likely evolved due to the two species eating different diets (see below).
Freshwater crocodiles are peculiar to northern Australia. Saltwater crocodiles inhabit a much broader area - as well as northern Australia, they can be found on the east coat of India, and historically throughout most of Southeast Asia, although their numbers have diminished considerably over time and they are now extinct in countries such as Thailand, Laos, and Vietnam.
Despite being able to tolerate saltwater freshwater crocodiles generally prefer freshwater environments, such as swamps, lakes, billabongs, and the upstream sections of rivers. It is rare for freshwater crocodiles to be found in saltwater.
Saltwater crocodiles, as their name suggests, prefer saline or brackish habitat. They can be found along the coastline and on beaches, as well as in estuaries, rivers, lagoons, and swamps.
4. Jawline and Teeth
Freshwater crocodiles have a straight jawline with teeth of relatively similar size. Saltwater crocodiles have an uneven jawline and their teeth vary in size, with some nearly double the size of others.
5. Salties are Bigger
One of the main differences between a freshwater crocodile and a saltwater crocodile is size. Freshwater crocodiles are much smaller than saltwater crocodiles, growing to approximately two meters (6.5 feet) in length, with males growing to be three meters (10 feet), and a maximum weight of 90kg (200lbs). Saltwater crocodiles, on the other hand, can reach six or seven meters (20 to 23 feet) in length and weigh over 1000kg (2,200lbs).
6. Different Diets
Adult freshwater crocodiles eat birds, fish, reptiles, bats, rodents, and amphibians. The size of the animal dictates the size of the prey, so larger animals will eat larger prey, such as wallabies.
Saltwater hatchlings and juveniles eat small fish, frogs, insects, birds and small reptiles. Adults will also consume larger prey, such as sharks, emu, hares, deer, dingos, gibbons, badgers monkeys, jackals, wallabies, wild pigs, and livestock. They will also eat humans.
7. Armored Plates
Saltwater crocodiles have much fewer armor plates on their neck in comparison to freshwater crocodiles. Freshwater crocodiles have closely-knit armored plates on their back, saltwater crocodiles does not.
Freshwater crocodiles also have large, broad body scales in comparison with saltwater crocodiles.
Did you know?
The saltwater crocodile is the world's largest living reptile. Although the average male is 5m in length, there are reports of individuals measuring more than 8m. Salties have a long lifespan. they can live for over 65 years.
Johnstone's crocodile is another name for the freshwater crocodile. The overall population of freshwater crocodiles is declining, likely due to the invasive species, cane toad, which is extremely poisonous to the freshwater crocodile (salties can tolerate their poison).
Saltwater crocodiles are very territorial and aggressive and, along with Nile crocodiles, are considered the most dangerous crocodiles to humans. The males have large territories and are capable of attacking and eating almost any animal that comes into their area, including people. Encounters with salties should be avoided at all costs.
Freshwater crocodiles, on the other hand, are less territorial and aggressive. They are not known as man-eaters and rarely kill people, although they will bite in self-defense if they are cornered. Freshies should be respected and people should keep their distance, even if the chances of being attacked are generally much smaller.
Staying Safe Around Crocodiles
- Avoid swimming in the same waters as saltwater crocodiles. They consider the area around them to be their territory. Stay away if you sight a saltwater crocodile on land.
- Areas around crocodile nests should always be avoided. These are typically found by the banks of a swamp, river, or estuary. Females will be extremely aggressive around their nests.
- Although freshwater crocodiles are generally less aggressive, they should be avoided during the months of July and August, as this is when they breed. Females become much more territorial and aggressive at this time.
- There is plenty of official travel advice available from the Australian government on which areas that have high numbers of saltwater crocodiles, so that you know where to avoid.
- "Crocodylus porosus". Animal Diversity Web
- "Saltwater Crocodile facts". Aquaticcommunity.com
- "Crocodylus porosus (Saltwater Crocodile). DIET". Herpetological Review
- Kar, S. K.; Bustard, H. R. (1983). "Saltwater crocodile attacks on man". Biological Conservation. doi:10.1016/0006-3207(83)90071-X
- Adam Britton. "Crocodylus johnstoni". Florida Museum of Natural History
- "Crocodiles falling victim to cane toads". ABC News
- Crocodile Specialist Group (1996). "Crocodylus johnsoni". IUCN Red List of Threatened Species
© 2018 Paul Goodman