Kangaroo leather

Key takeaways

Kangaroo leather belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Kangaroo leather to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Kangaroo leather from memory before moving on to harder problems.

Reference excerpt

Kangaroo leather is a strong, lightweight leather derived from the hide of the kangaroo. Kangaroos are harvested. Both the meat and the hides are sold. Although hunting most species of macropod is prohibited, a small number of the large-sized species with high populations can be hunted by commercial hunters. This policy has been criticised by some wildlife activists.

Applications

The leather is used in a wide variety of shoes. The unique structure of kangaroo leather allows it to be cut down to be very thin, but still retain strength. Kangaroo leather is also popular in the manufacture of motorbike leathers and is used for many other applications such as car upholstery, military, football and American football boots, and fashion accessories. Kangaroo leather is the material of choice for making whips, as the strips can be cut thin to keep the whip flexible, without sacrificing durability.

Properties Studies conducted by the Australian Commonwealth Scientific and Industrial Research Organisation (CSIRO) confirm that kangaroo is one of the strongest leathers of similar substance available. When split thinly, kangaroo leather retains considerably more of the original tensile strength of the unsplit leather than does calf leather. When split to 20% of original thickness kangaroo retains 30 to 60% of the tensile strength of the unsplit hide. Calf split to 20% of original thickness, on the other hand, retains only 1–4% of original strength. Kangaroo leather is lighter and stronger than the hide of a cow or goat. It has 10 times the tensile strength of cowhide and is 50% stronger than goatskin. Studies of the morphology of kangaroo leather help explain its particular properties. The collagen fibre bundles in cattle hide are arranged in a complex weaving pattern. The fibres are often at angles as much as 90 degrees to the skin surface. Cattle hide also contains sweat glands, erector pili muscles and a distinct gradation in elastin levels, concentrated in the upper part of the skin. Kangaroo hide on the other hand has been shown to have a highly uniform orientation of fibre bundles in parallel with the skin surface. It does not contain sweat glands or erector pili muscles, and elastin is evenly distributed throughout the skin thickness. This structural uniformity explains both the greater tensile strength of the whole leather and the greater retention of strength in splits. Bovine skin is much more complex in cross-section; in whole section it has many more weak points from which tears can start when placed under tension. In addition, when split the collagen fibres running at significant angles to the skin surface will be cut, becoming weak points.

Environmental aspects The Australian kangaroo industry produces a range of meat and leather products from animals harvested from the wild under strict government-controlled management plans intended to ensure that the harvest is sustainable and humane. A wide cross section of Australian ecologists support the kangaroo industry as being both sustainable and environmentally wise. Many argue that kangaroos, native to Australia, are a more environmentally friendly livestock option than introduced sheep and cattle. The two most important facets of kangaroos' better ecological fit than European agricultural animals relate to their adaptation to Australia's aridity. Kangaroos have small chest development and so require less water to breathe than placental mammals, which usually must expand a diaphragm, losing more moisture in respiration. Kangaroos just make small pants while immobile, and in motion expand and contract their lungs effectively using their leg muscles. The belly flops up, contracting the lungs, and down, expanding them. The kangaroo's paws are softer and do not compact the ground as hoofed cattle and sheep do. Instead, its hopping leaves very small bowl-shaped depressions in the surface of even dry clay soil, which let native grass seeds carried on the wind settle into them. The bowl shape concentrates any moisture that may fall into it into a wet point that the grass seed can use to germinate. Thus, kangaroos deplete the water table more slowly than cattle or sheep, and would even be viable in the absence of any bore water. The ecological arguments for kangaroos replacing sheep and cattle as arid land livestock are compelling, though they must be set against objections of kangaroos' lack of domestication and breeding rate. Kangaroos are eaten in most states.

Worked examples

Example 1 — a first encounter with Kangaroo leather

Start with the simplest possible case. Write down what Kangaroo leather claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Kangaroo leather before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Kangaroo leather ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Kangaroo leather

In research: Kangaroo leather appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Kangaroo leather in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Kangaroo leather is common in secondary-school and first-year university syllabi. It links to neighbouring topics Kangaroos and wallabies and humans, Leather, Leathermaking, so understanding it makes those chapters shorter.
In everyday life: Look for Kangaroo leather outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study Kangaroo leather in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Kangaroo leather means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Kangaroo leather out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Kangaroo leather in simple terms?

Kangaroo leather is a strong, lightweight leather derived from the hide of the kangaroo. Kangaroos are harvested.

Why does Kangaroo leather matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Kangaroo leather?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Kangaroo leather.