Why Evolution Made Humans The Biggest Primate Down There (Gorillas Have It Way Worse)

Why did evolution make humans the biggest primate down there, while a 400-pound silverback gorilla gets an inch or two? The answer runs through muscle, rivals, standing up and two things our DNA threw away. This video breaks down why the weakest great ape ended up with the boldest anatomy, and what it cost us. This video covers: • Gorilla vs chimpanzee vs human anatomy compared • Why gorillas compete with muscle and chimps with sperm volume • How walking upright and losing body hair put us on display • The 2013 study of 343 life-size figures and female mate choice • The Stanford study of lost DNA switches and penile spines • Why humans lost the baculum, the bone other apes still have • The honest-signal idea and why biologists still debate it Gorilla, chimp or human: if you had to pick one setup for life, which would you choose? Subscribe for more strange stories of human evolution. ────────── Sources: Harcourt, Harvey, Larson & Short — Testis weight, body weight and breeding system in primates, Nature, 1981 McLean, Kingsley et al. — Human-specific loss of regulatory DNA and the evolution of human-specific traits, Nature, 2011 Mautz, Wong, Peters & Jennions — Penis size interacts with body shape and height to influence male attractiveness, PNAS, 2013 Brindle & Opie — Postcopulatory sexual selection influences baculum evolution in primates and carnivores, Proceedings of the Royal Society B, 2016 Veale et al. — Am I normal? Nomograms for flaccid and erect penis length and circumference, BJU International, 2015 Dixson & Mundy — Sexual behavior, sexual swelling, and penile evolution in chimpanzees, Archives of Sexual Behavior, 1994 Toups et al. — Origin of clothing lice indicates early clothing use by anatomically modern humans in Africa, Molecular Biology and Evolution, 2011 Waldinger et al. — A multinational population survey of intravaginal ejaculation latency time, Journal of Sexual Medicine, 2005 Stanford Medicine News — Differences in mammalian brain structure and genitalia linked to specific DNA regions, 2011 Berggorilla & Regenwald Direkthilfe — What do a silverback's genitals look like? Mark Maslin, The Conversation — Why did humans evolve big penises but small testicles?, 2017 CARTA Matrix of Comparative Anthropogeny — Penis Size and Morphology Disclaimer: For educational and entertainment purposes. Some interpretations are actively debated among researchers and may change as new evidence emerges. Not professional advice. #HumanEvolution #EvolutionaryBiology #Gorilla #Primates #Anthropology #Chimpanzee