---
title: "Aquatic ape hypothesis"
chunk: 1/4
source: "https://en.wikipedia.org/wiki/Aquatic_ape_hypothesis"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T03:37:25.340882+00:00"
instance: "kb-cron"
---

The aquatic ape hypothesis (AAH), also referred to as aquatic ape theory (AAT) or the waterside hypothesis of human evolution, postulates that the ancestors of modern humans took a divergent evolutionary pathway from the other great apes by becoming adapted to a more aquatic habitat. While the hypothesis has some popularity with the lay public, it is generally ignored or classified as pseudoscience by anthropologists.
The theory developed before major discoveries of ancient hominin fossils in East Africa. The hypothesis was initially proposed by the English marine biologist Alister Hardy in 1960, who argued that a branch of apes was forced by competition over terrestrial habitats to hunt for food such as shellfish on the coast and seabed, leading to adaptations that explained distinctive characteristics of modern humans such as functional hairlessness and bipedalism. The popular science writer Elaine Morgan supported this hypothesis in her 1972 book The Descent of Woman. In it, she contrasted the theory with zoologist and ethologist Desmond Morris's theories of sexuality, which she believed to be rooted in sexism.
Anthropologists do not take the hypothesis seriously: John Langdon characterized it as an "umbrella hypothesis" (a hypothesis that tries to explain many separate traits of humans as a result of a single adaptive pressure) that was not consistent with the fossil record, and said that its claim that it was simpler and therefore more likely to be true than traditional explanations of human evolution was not true. According to anthropologist John Hawkes, the AAH is not consistent with the fossil record. Traits that the hypothesis tries to explain evolved at vastly different times, and distributions of soft tissue the hypothesis alleges are unique to humans are common among other primates.

== History ==
In 1942 the German pathologist Max Westenhöfer (1871–1957) discussed various human characteristics (hairlessness, subcutaneous fat, the regression of the olfactory organ, webbed fingers, direction of the body hair etc.) that could have derived from an aquatic past, quoting several other authors who had made similar speculations. As he did not believe human beings were apes, he believed this might have been during the Cretaceous, contrary to what is possible given the geologic and evolutionary biology evidence available at the time. He stated: "The postulation of an aquatic mode of life during an early stage of human evolution is a tenable hypothesis, for which further inquiry may produce additional supporting evidence." He later abandoned the concept.
Independently of Westenhöfer's writings, the marine biologist Alister Hardy had since 1930 also hypothesized that humans may have had ancestors more aquatic than previously imagined, although his work, unlike Westenhöfer's, was rooted in the Darwinian consensus. On the advice of his colleagues, Hardy delayed presenting the hypothesis for approximately thirty years. After he had become a respected academic and knighted for contributions to marine biology, Hardy finally voiced his thoughts in a speech to the British Sub-Aqua Club in Brighton on 5 March 1960. Several national newspapers reported sensational presentations of Hardy's ideas, which he countered by explaining them more fully in an article in New Scientist on 17 March 1960: "My thesis is that a branch of this primitive ape-stock was forced by competition from life in the trees to feed on the sea-shores and to hunt for food, shellfish, sea-urchins etc., in the shallow waters off the coast."
The idea was generally ignored by the scientific community after the article was published. Some interest was received, notably from the geographer Carl Sauer whose views on the role of the seashore in human evolution "stimulated tremendous progress in the study of coastal and aquatic adaptations" inside marine archaeology. In 1967, the hypothesis was mentioned in The Naked Ape, a popular book by the zoologist Desmond Morris, who reduced Hardy's phrase "more aquatic ape-like ancestors" to the bare "aquatic ape", commenting that "despite its most appealing indirect evidence, the aquatic theory lacks solid support".
While traditional descriptions of 'savage' existence identified three common sources of sustenance: gathering of fruit and nuts, fishing, and hunting, in the 1950s, the anthropologist Raymond Dart focused on hunting and gathering as the likely organizing concept of human society in prehistory, and hunting was the focus of the screenwriter Robert Ardrey's 1961 best-seller African Genesis. Another screenwriter, Elaine Morgan, responded to this focus in her 1972 Descent of Woman, which parodied the conventional picture of "the Tarzanlike figure of the prehominid who came down from the trees, saw a grassland teeming with game, picked up a weapon and became a Mighty Hunter," and pictured a more peaceful scene of humans by the seashore. She took her lead from a section in Morris's 1967 book which referred to the possibility of an Aquatic Ape period in evolution, his name for the speculation by the biologist Alister Hardy in 1960. When it aroused no reaction in the academic community, she dropped the feminist criticism and wrote a series of books–The Aquatic Ape (1982), The Scars of Evolution (1990), The Descent of the Child (1994), The Aquatic Ape Hypothesis (1997) and The Naked Darwinist (2008)–which explored the issues in more detail. Books published on the topic since then have avoided the contentious term aquatic and used waterside instead.

== The Hardy/Morgan hypothesis ==
Hardy's hypothesis as outlined in New Scientist was: