switch rapidly between aggressive mimicry and defensive behavior depending on whether they are in the presence of a prey or a potential predator. For example, the sidewinder rattlesnake ceases aggressive behavior upon the arrival of a predatory toad and begins species-typical defensive displays. Host-parasite Host-parasite mimicry is a form of aggressive mimicry in which a parasite mimics its own host. Brood parasitism is a common form of parasitic aggressive mimicry that occurs in vertebrates, with cuckoos being a notable example. Brood parasite mothers will surrender their offspring to be raised by another organism, of either the same or a different species, unbeknownst to the other organism. This allows the progeny to be nurtured without energy expenditure or parental care by the true parent. Cuckoos are brood parasites that lay their eggs to match the color and pattern of their host's own eggs. Different species of cuckoo hatchlings have been known to mimic the acoustic sound, such as during begging, and appearance of the host offspring. Unlike most vertebrates that perform aggressive mimicry, certain brood parasitic birds display signals of two distinct modalities at the same time. For example, Horsfield's bronze cuckoo nestlings have been found to employ both acoustic and visual sensory modalities at the same time to increase efficiency and success of their mimicry. However, host-parasite systems are not always as precise. Great spotted cuckoos are brood parasites that lay eggs that can successfully dupe other birds such as the magpie, pied starling, and black crow, despite having different egg color, egg size, and offspring features. It is hypothesized that these differences in characteristic have evolved after the mimicry system due to genetic isolation, as the appearance of eggs laid by European an African great spotted cuckoos are different. Evidence also exists for other forms of parasitic mimicry in vertebrates. One such form is interspecific social dominance mimicry, a type of social parasitism where a subordinate species (usually determined by size) evolves over time to mimic its dominant ecological competitor, thereby competing with its previously socially dominant opponent. One such example is found in the tyrant flycatcher family, in which different birds of similar appearance exist from six different genera. Smaller-bodied species from four genera have been found to mimic the appearance of the larger species of the other two genera, suggesting that an avian mimicry complex has contributed to convergent evolution, providing a competitive advantage in the same