Great Hippocampus Question

The Great Hippocampus Question was a 19th-century scientific controversy about the anatomy of apes and human uniqueness. The dispute between Thomas Henry Huxley and Richard Owen became central to the scientific debate on human evolution that followed Charles Darwin's publication of On the Origin of Species. The name comes from the title of a satire the Reverend Charles Kingsley wrote about the arguments, which in modified form appeared as "the great hippopotamus test" in Kingsley's book for children, The Water-Babies, A Fairy Tale for a Land Baby. Together with other humorous skits on the topic, this helped to spread and popularise Darwin's ideas on evolution.

The key point that Owen asserted was that only humans had part of the brain then known as the hippocampus minor (now called the calcar avis), and that this gave us our unique abilities. But careful dissection showed that apes and monkeys also have a hippocampus minor.

In October 1836 Charles Darwin returned from the Beagle voyage with fossil collections which the anatomist Richard Owen described, contributing to the inception of Darwin's theory of natural selection. Darwin outlined his theory in an Essay of 1844, and discussed transmutation with his friend Joseph Dalton Hooker. He did not tell Owen, who as the up-and-coming "English Cuvier" held the conventional belief that every species was uniquely created perfectly adapted. Owen's brilliance and political skills made him a leading figure in the scientific establishment, developing ideas of divine archetypes produced by vague secondary laws similar to a form of theistic evolution, while emphasising the differences separating man from ape. At the end of 1844 the anonymous book Vestiges of the Natural History of Creation brought wide public interest in transmutation of species and the idea that humans were descended from apes, and after a slow initial response, strong condemnation from the scientific establishment.

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