Home > Aquatic ape hypothesis

holds that the immediate ape ancestors of humans and other hominids lived for a significant time in a semi-aquatic setting on the African seacoast, that they gathered most of their food from the seashore and shallow offshore waters before their hominid descendants returned to a more land-based existence, and that adaptations to this marine Environment of Evolutionary Adaptedness can be identified in the modern human phenotype.

This is a minority position not widely held in biology. The conventional view of human evolution is that the first hominids evolved in terrestrial environments.

The hypothesis was originally suggested in 1960 by the marine biologist Sir Alister Hardy (1896-1985). The feminist writer Elaine Morgan developed and promoted it, publishing her first book on the subject, The Descent of Woman , in 1972. Her later books on the subject are: The Aquatic Ape (1982), The Scars of Evolution (1990), and The Aquatic Ape Hypothesis (1997).

1 Outline

The aquatic ape hypothesis puts forward these main arguments:

• Nakedness: Of the hundreds of primate species, humans are the only species in which hair does not cover almost the entire body. The only environments known to give rise to naked mammals are aquatic and subterranean. Other naked mammals are totally subterranean ( naked mole rat), swim ( whaleWhales are the largest species of exclusively aquatic placental mammals, dfsgRSFNjg A complete up-to-date taxonomical listing of all cetacean species, including all whales is maintained at the Cetacea article. Anatomy Like all mammals, whales breathe air, dolphinThis article is about the dolphin mammal. For other uses of the term, please see dolphin (disambiguation). See article below. Dolphins are certain aquatic mammals related to whales and porpoises. The word is used in a few different ways. It can mean: #any, walrusrosmarus rosmarus ''O. rosmarus divergens Walruses are large semi-aquatic mammals that live in the cold Arctic seas of the Northern Hemisphere. The two subspecies are the Atlantic, Odobenus rosmarus rosmarus and the Pacific, Odobenus rosmarus divergens''. and manateeTrichechus inunguis ''Trichechus manatus ''Trichechus senegalensis Manatees ( family Trichechidae genus Trichechus are large aquatic mammals sometimes known as sea cows . The Trichechidae differ from the Dugongidae in the shape of the skull and the shape), wallow ( hippopotamusThe Hippopotamus Hippopotamus amphibius is a large, plant-eating African mammal, one of only two living and three (or four) recently extinct species in the family Hippopotamidae. Hippopotamuses ('hippopotami' is also accepted as a plural form by the OED),, pigThe domestic pig is usually given the scientific name Sus scrofa though some authors call it S. domesticus reserving S. scrofa for the wild boar. It has been a domesticated animal for approximately 5,000 to 7,000 years. The animal is found across Europe, and tapirTapirus bairdii Baird's Tapir Tapirus indicus Malayan Tapir Tapirus pinchaque Mountain Tapir Tapirus terrestris Brazilian Tapir A tapir is a large, browsing animal, roughly the shape of an over-sized pig but with a short, prehensile trunk. Size varies wit) or seek mud and water regularly ( rhinoceros and elephant).

• Bipedalism: Humans are the only surviving bipedal mammal. Although it gives us the ability to use tools whilst walking or running, it directly causes the following problems: back problems, knee problems, varicose veins, hemorrhoids, hernias and problems with childbirth.

Since evolution works in small steps, it is hard to see how bipedalism could have evolved on the savanna: the mass of the torso makes bipedalism inherently unstable and inefficient. Bipedalism is not observed in other savanna animals. Water, however, supports the body, and non-human primates such as bonobos and proboscis monkeys have been observed wading bipedally in their occasionally flooded habitats.

• Breathing: With the exception of humans and a few other outstanding animals (many of which had aquatic ancestry like the elephant), land mammals have no conscious control over their breathing. The voluntary control humans have over their respiratory system is similar to that of aquatic mammals which inhale as much air as they need for a dive, then return to the surface for air.

• Fat: Humans have ten times as much fat in our bodies as is normal in an animal of our size. We are by far the fattest primates. Mammals which hibernate have seasonal fat: aquatic mammals, like humans, retain fat throughout the year.

• Childbirth: Dramatic increase in the size of the cranium is a prominent theme in human evolution, making childbirth difficult and dangerous. Water birthing is known to facilitate childbirth and to reduce risks to mother and infant. Human infants are born covered in vernix caseosa, a waterproof coating, and continue to draw oxygen through the umbilical cord while underwater.

• Nutrition: Human brain tissue requires comparatively large amounts of omega-3 fatty acids, which are uncommon in the land food chain but prevalent in the marine food chain.

• Tears and excessive sweating, prevalent in humans but not in other primates, are considered further evidence to support the hypothesis, insofar as they are vectors for the removal of excess salts from the body, as might result from the ingestion of saltwater. Other marine animals, such as the marine turtle , secrete tears for this purpose, although these tears are of higher salinity than human tears.

• Supporters of the hypothesis also mention the webbing between the human thumb and fore finger, which has no apparent value on land.

One difficulty in evaluating this hypothesis is that the places it suggests fossils might be found are mostly below sea level at the present epoch.