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 10 hard defenses DHJanzen100249.jpg high resolution
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| This not a secondary compound defense. In some ways it is an analogue to the cellulose of the tree trunk, and the lignin and stone cells of hard-walled nuts and hard seed coats. But, aside from molluscs in the sea where calcium carbonate is not exactly hard to come by, bundling up in a coat of truly hard armour - as does the turtle - is no substitute for the escape and defense behavior so common in animals. It leads to immobility (not much of a concern to a tree) and can be overcome by simply more power. In Africa, where big carnivores abound, there is even a quite sprightly turtle with a soft shell, expert at escaping by running to a crack in the soil or between rocks and squeezing in. | ||
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