A comparison of the salt water crocodile and fresh water crocodile| ||
Figure 1 – Saltwater CrocodileFigure 2 – Freshwater Crocodile
I declare that the work submitted is my own with no part written/produced for me by any other person. I have acknowledged the people who have provided assistance and the materials referred to in developing my ideas have been acknowledged according to the school referencing system.
Table of contents
Summary of adaptations| 3|
Annotated Bibliography| 9|
The fresh water crocodile (Crocodylus johnstoni) and the salt water crocodile (Crocodylus porosus) are two Australian species that have evolved from their ancient ancestors 80 million years ago. These prehistoric reptiles come from the Crocodylidae family and are one of the most intelligent reptiles. From 1940 – 1970, salt water crocodiles were hunted for their hides which resulted in reduced numbers in the population. In the 1950’s, the hunting of fresh water crocodiles increased due to advances made in tanning processes. This meant they could use the skin of the fresh water crocodile instead of salt water crocodiles for leather, which caused a decrease in their population. In 1962, crocodiles were protected by law in Western Australia and then in the Northern Territory in 1964. They weren’t protected in Queensland until 1974. Illegal hunting of crocodile skins still continues but their main threat is destruction of habitat. Both of these species have had to adapt to Australia’s changing climate to survive. The adaptations of these species including their similarities and differences will be discussed and compared, along with a prediction of which species is more likely to survive in Australia.
Summary of adaptations
These tables show the structural, behavioural and functional adaptations of the Salt water crocodile (Table 1) and the freshwater crocodile (Table 2).
Table 1: adaptations of the Salt water crocodile
Structural| Behavioural | Functional|
Strong jaw muscles| Will attack humans if threatened| Salt glands on tongue| Eyes and nose on top of head| Lunge at prey and eat underwater| Metabolism | Broad skull and uneven jaw line| | Acidic stomach|
Table 2: adaptations of the Fresh water crocodile
Structural| Behavioural| Functional|
Narrow skull and even jaw line| Generally shy and flee from humans| Salt glands on tongue| Eyes and nose on top of head| ‘high walk’| Metabolism| | Fast gallop| Acidic stomach|
| ‘sit-and-wait’ method for prey| |
There are many similarities between the salt water crocodile and the fresh water crocodile. The Salt Water Crocodile and the Fresh water Crocodile are both carnivores and have a variety of prey within their Australian habitat. They also have few predators when mature; other crocodiles and the cane toad. They both possess structural, functional and behavioural adaptations to help them survive. They are tough creatures with permanent bony plates that cover most of their body and strong jaw muscles. Both these structural features help the crocodiles to defend themselves from predators and survive. Both the salt water crocodile and the fresh water crocodile have their eyes and nose on the top of their head, which enables the rest of their body to stay underwater. These are structural adaptations that help them to survive and kill their prey. Both crocodiles have special glands on their tongue that excrete salt, which enables them to live in salty waters, and they can both live in fresh water (Australian Museum, n.d.).
Figure 3 – Eyes and nose on top of head – Salt water crocodile