The work of the ethologists showed the strong genetic basis for most animal behaviors. Of course, most animals are insects and other invertebrates, and even among the vertebrates most are not mammals, let alone primates. So even though the controversy over the relative influences of nature versus nurture in human behavior has raged for many years, the dominant role played by genes in shaping behavior is amply documented by research on other species. Genetically determined complex behaviors such as the web spinning of spiders or the mating behaviors of dabbling ducks mentioned above must surely depend on many genes. Yet with the rapid development of genomic analytical technologies, comparisons of genomes of animals with different behavioral phenotypes are producing many examples of single gene alterations that produce behavioral differences.