[hhjinks]

> intelligence + longlivety does not provide immediate advantage

You gotta wonder what sort of environmental pressures make intelligent animals less fit for survival by creating communities. Few predators? Very simple environments that don't require passing on information to future generations? High competition for resources?

[nabla9]

Energy and nutritional requirements, longer time before reaching adulthood. For humans one of the limiting factor is the female pelvis. Births become more difficult.