"Cassytha" fruits are ecologically valuable to some fruit-eating birds. The birds either regurgitate the seeds or pass them through their guts. Mammals, for example Australian macropods, also transport the seeds in their guts. The bony endocarp that protects the seed in its passage through animal guts also prevents the seed from immediate germination even if conditions are favourable. Instead, the seeds survive on or in the ground till decay weakens the endocarp sufficiently to permit moisture to enter and germination to begin. This process is not deterministic, so some of the seeds might remain inactive in the soil seed bank for many years before they germinate at unpredictable intervals. Accordingly, once soil is infested with large numbers of seeds, eradication of the population generally takes a long time. On germination, the seedlings behave as aggressive parasites; they twist about till they find a host, and those that fail to locate hosts soon die, typically in a matter of months.