The tough, nutrient-poor leaves of fynbos are indigestible to most animals, apart from some highly adapted browsers like klipspringer and grysbok. Tortoises are probably the best adapted nibblers, as they can eat plants that are not only unpalatable, but are positively poisonous to other animals.
To counteract these clever adaptations by animals, many plants have devised ways of protecting themselves against being eaten. This might be by the use of spikes and prickles, as in the gorse family. Others use chemical weapons to make their leaves very unpleasant, and are sometimes poisonous enough to stop the heart, liver and other major organs of the unfortunate grazer. These toxins can be potent enough to kill an animal the size of a cow. The virginal-white arum lily has developed shards of crystals to keep animals from eating it, although some caterpillars still manage to avoid the consequences and nibble perfectly round holes in the exquisite flowers.
Sub-Saharan molerats are very large compared to European moles and the Dune molerat is the largest of all subterranean rodents. It weighs up to 1.5 kilograms and creates mole hills half a metre high – much to the chagrin of gardeners. Molerats have developed tolerance to several toxins in bulbs, some of which contain enough poison to kill a horse. These molerats play an important part in dispersion of bulbs, because they store some in burrows which then sprout and grow to the surface. This explains the occurrence of bulbs in dense clumps.
Read this post on how birds have learnt to survive.