4 ms·

My personal favourite is the hypothesis that human ancestors had for an extended period lived wading in shallow water, which protected them from climate (i.e. e

My personal favourite is the hypothesis that human ancestors had for an extended period lived wading in shallow water, which protected them from climate (i.e. either warm springs in cold climate, or regular water in warm ones; we can see similar behaviour among modern monkeys and apes in some circumstances [0]) and possibly from natural predators. They were not constrained to the water, often leaving it to forage for food and possibly hunt, but regularly returning to its safety. Eventually the climate changes forced them to leave the wading lifestyle and adapt to steppes and other habitats, using their growing intellect to devise adaptations like clothes, tools and at some point mastery of fire. This would, in my mind, explain a number of specific development present in humans in a very rare combination: - nearly complete loss of body hair, except on the head (which is consistent with wading) - adaptations for both swimming/diving and two-legged walk - development of speech and facial expressions as communication tools, which work the best when the rest of the body cannot be used - importance of fish in human diet - increased brain in children, which causes more difficult births, which are offset but giving birth in water This is a variant of what used to be known as "aquatic ape hypothesis" and widely ridiculed, but more resent research has supported some of its elements [1]. [0] https://www.seejapan.co.uk/where-to-go/outdoors/hot-springs/snow-monkeys-hot-springs https://www.seejapan.co.uk/where-to-go/outdoors/hot-springs/... [1] https://en.wikipedia.org/wiki/Aquatic_ape_hypothesis#Related_academic_and_independent_research https://en.wikipedia.org/wiki/Aquatic_ape_hypothesis#Related...

Swizec 8y ago
> - nearly complete loss of body hair, except on the head (which is consistent with wading) It's also consistent with running. Running creates a lot of energy. Like a lot. You know when it's sub 10 celsius out and everyone is freezing their butts off? You go for a run in tiny tiny shorts and a tiny little t-shirt and yes it's freezing your nips off but 3 miles later you're sweating balls and wishing the t-shirt was smaller and the shorts even tinier. They say the perfect temperature for a marathon is around 4 celsius. That's because when you're fast enough, heat dissipation is pretty much the only limiting factor to how fast you can run. Even an amateur runner like me can see huuuuuge gains in speed just from running in temperate winter instead of during summer.
- BerislavLopac 8y ago
  Many animals run and still retain their fur. Pretty much all of the known mammals that have lost most of their fur/hair are either aquatic (whales, dolphins, dugongs...) or regular waders (pigs, hippos, elephants...); the only exceptions live underground or in crevices.

Swizec 8y ago

> - nearly complete loss of body hair, except on the head (which is consistent with wading) It's also consistent with running. Running creates a lot of energy. Like a lot. You know when it's sub 10 celsius out and everyone is freezing their butts off? You go for a run in tiny tiny shorts and a tiny little t-shirt and yes it's freezing your nips off but 3 miles later you're sweating balls and wishing the t-shirt was smaller and the shorts even tinier. They say the perfect temperature for a marathon is around 4 celsius. That's because when you're fast enough, heat dissipation is pretty much the only limiting factor to how fast you can run. Even an amateur runner like me can see huuuuuge gains in speed just from running in temperate winter instead of during summer.

BerislavLopac 8y ago
Many animals run and still retain their fur. Pretty much all of the known mammals that have lost most of their fur/hair are either aquatic (whales, dolphins, dugongs...) or regular waders (pigs, hippos, elephants...); the only exceptions live underground or in crevices.