North Pacific right whale
In 2000, Rosenbaum et al. disagreed, based on data from their genetic study of DNA samples from each of the whale populations. Genetic evidence now clearly demonstrates that the northern and southern populations of right whale have not interbred for between 3 million and 12 million years, confirming the southern right whale as a distinct species. The northern Pacific and Atlantic populations are also distinct, with the North Pacific right whale being more closely related to the "southern" right whale than to the North Atlantic right whale. Genetic differences between "E. japonica" (north pacific) and "E. australis" (south pacific) are much smaller than other baleen whales represent among different ocean basins.