Prior to the 1970s, estuarine crocodiles were hunted extensively for their skins — as a result their number were drastically reduced. After three decades of unregulated hunting, numbers across the Kimberley and the Northern Territory (NT) fell to less than 8000 individuals. Scientists have been collecting data to assess the distribution and abundance of crocodiles to gain an understanding of the extent to which the populations are recovering.
Representing the Traditional owners of north-west Australia, the Kimberley Ranger Network provides the frontline in current management practices in the region. Using a combination of traditional knowledge, Western science and modern technologies to improve marine conservation and management outcomes, the Rangers are tasked with protecting the unique biodiversity values of this beautiful region.
This lesson focuses on the analysis of a dataset that records scientific data collected about the crocodile population in the Kimberley region during 2015. The lesson follows an inquiry process where students use the dataset to answer relevant questions about the crocodile population. It also provides an opportunity for students to learn about Aboriginal and Torres Strait Islander histories and cultures, and sustainability. It also provides suggestions to be gender-responsive, with Girls in Focus tips.
2015 Crocodile Survey results plotted on Google Maps
Map data © 2019 Google
Use a relevant hook to engage students to discover more about saltwater crocodiles. You could introduce a dilemma to encourage students to consider a range of issues and concerns where they need to balance social, ethical, economic, conservation and cultural perspectives. In the student task we have used the dilemma: ‘Should crocodile trophy hunting be permitted in the Kimberley?’
To support students use the inquiry questions and sample answers guide.
Research has shown that girls are interested in careers that have a positive social impact. This topic shines a spotlight on a contemporary issue that requires a balance of social, ethical, economic, conservation and cultural perspectives.
Some students may be interested in the link between crocodile farming and fashion (see: AgriFutures: Crocodiles). This approach to combining business with conservation has interesting similarities to trophy hunting.
Research has shown that girls value interaction and collaboration. Promote collaboration and recognition of the varied skills within the team, ensuring that all students are given the opportunity to manipulate the data set.
Research has shown that when girls are exposed to positive STEM role models, their interest increases, along with an improved self-concept related to STEM fields. When showing scientists in action and use of technology, provide a balanced representation of males and females.
Girls often have a poor self-concept as mathematicians, believing commonly-held stereotypes that boys are naturally better than girls at maths. If you observe a number of girls showing reluctance or a lack of confidence with using spreadsheets, consider offering an additional session to practise and improve their skills. Support a growth mindset by praising their effort, strategies and behaviours.
The inquiry provides a useful opportunity to include a cultural perspective. Aboriginal people have been managing their land and sea country in north-west Australia for more than 40,000 years. With spiritual beliefs and way of life closely linked to country, Aboriginal people have an intimate knowledge of their environment deeply embedded in their culture, language, traditions and stories. Recognise the work of the Kimberley Ranger Network, who provide the frontline in current management practices in the region. Discuss the use of a combination of traditional knowledge, Western science and modern technologies to improve marine conservation and management outcomes.
Provide guidance and support for students to use data overlays using online mapping software. The overlays show Indigenous Land Use Agreements and Indigenous Protected Areas. Discuss what this data demonstrates and how it may be used in their inquiry. Refer to the crocodile data displayed in the North West Atlas.
Image: Distribution, abundance, critical habitat and population growth rates of saltwater crocodile populations in the Kimberley region
Add Overlay layers, which can be found by clicking the green '+' icon in the 'Overlays' section, selecting 'Overlay layers', and then searching in the folder North West Atlas and WAMSI sub folder.
Research suggests that girls are motivated when they are given opportunities to approach projects their own way, exercising their personal preferences and creativity. Engaging with creative problem solving also encourages students to embrace failure as part of the learning process, building resilience.
Inquiry questions with possible sample answers guide.
A table of results sorted and a count for each length
|1 foot (0.3 m)||219||Most common|
|2 foot (0.61 m)||22|
|3 foot (0.91 m)||206|
|4 foot (1.22 m)||124|
|5 foot (1.52 m)||199|
|6 foot (1.83 m)||142|
|7 foot (2.13 m)||117|
|8 foot (2. 44 m)||39|
|9 foot (2.74 m)||25|
|10 foot (3.05 m)||22|
|11 foot (3.35 m)||5|
|12 foot (3.66 m)||6|
|13 foot (3.96 m)||1|
|14 foot (4.27 m)||2||Largest|
Map data © 2019 Google
Crocodiles by size, sighted in Prince Regent River system during three studies (1978, 1985 and 2015)
|up to 0.6m||56||5||82|
|0.6 up to 0.9 m||14||12||6|
|0.9 up to 1.2 m||18||26||88|
|1.2 up to 1.5 m||24||29||67|
|1.5 up to 1.8 m||20||29||118|
|1.8 up to 2.1 m||20||55||84|
Encourage students to recognise that there is overlap of crocodile data points and shaded areas on the Indigenous Land Use Agreements 2017 and Indigenous Protected Areas 2017 maps. This indicates that the Traditional land owners are a significant stakeholder and must be part of any discussions and proposed management strategy.
Digital Technology focus
GPS enables researchers to plot an accurate location for each individual crocodile. Digital systems such as laptop, tablet or similar with a data entry app enable immediate data entry and uploading of data using cloud technology for sharing and collaboration.
Location data (longitude and latitude) enables accurate plotting of animal location on a map using mapping software.
Once the data is cleaned up, it can be sorted and filtered according to the question being answered. Typically the data is sorted by columns based on the cell’s value or text. Sorting allows for grouping entries by a common attribute, which helps identify patterns or trends in data.
Discrete or continuous data.
Eggs may not survive to hatching due to predation of goannas and feral pigs or issues to do with the eggs themselves or nesting site conditions. Hatchlings are often taken by predators before they mature. Smaller crocodiles may be attacked by larger crocodiles. Many crocodiles are still killed accidently in fishing nets. Some eggs and crocodiles are taken from the wild for commercial crocodile farms. Occasionally crocodiles are removed from an area.
The length of the animal is proportional to its age. Crocodiles measuring < 0.6 m are considered hatchlings of that year. Juvenile crocodiles are > 0.6 to < 1.5 m. A 1.5–2 m crocodile is considered a young adult. Crocodiles larger than 2 m are considered adult.
Surveys are conducted by boat travelling upstream at night when most crocs are on shore or relatively stationary. Based on the speed of the vessel, direction of travel and that it’s at night time, it’s unlikely crocs would be moving around and past the vessel to be counted again (though not impossible).
Consider the available and emerging technology, safety, staff required and skills, ethical collection techniques and links to historical data.
To ensure meaningful comparisons can be made from historical data, it is important that the same methodology be used and consistent data is collected using the same parameters.
Acquire data examines how we collect and access data from a variety of sources.
Students can generate data of various types through their own experiments and investigations.
Record data in a format that allows it to be easily accessed or obtained. Students can describe how the data they have acquired can be stored in different ways using different representations and/or software, and select the most suitable representation is important.
Organise data explores the ways we order, sort and arrange data to assist us with interpretation in different contexts.
Use data and its characteristics, properties and patterns to form a conclusion or derive meaning from it. Students can work with data that requires some simple processing using software. This could be in the form of things such as simple spreadsheet calculations or using data in code. They draw conclusions about the data as a result of this processing.
Saltwater crocodiles: WAMSI Project information: distribution, abundance, critical habitat and population growth rates of saltwater crocodile populations in the Kimberley region. Includes fact sheet and video that explains scientific sampling of crocodiles.
Crocs get it on: An ABC News article about saltwater crocodiles which provides useful background information.
Estuarine Crocodile: An Australian Museum article about saltwater crocodiles which provides useful background information.
Dozens of saltwater crocodiles so dangerous they've been plucked from the wild to live out their days at Western Australia's only crocodile park.
Refer to the crocodile data displayed in the North West Atlas.
Plotting spatial data (longitude and latitude) using Google Maps: My Maps.
Andrew Halford, Daniel Barrow: Saltwater crocodiles (Crocodylus porosus) in the northwest Kimberley
WAMSI 2 – Kimberley Node – 1.2.3 – Distribution, abundance, critical habitat and population growth rates of saltwater crocodile populations in the Kimberley region: Metadata for Andrew Halford, Daniel Barrow article
Crocodile tagging in Kakadu. Watch this video for an example of scientists (male and female) tagging crocodiles.