I think Hobbes and Darwin would both object to being grouped in with Rand. Hobbes would say the world is violent therefore we should take measures to protect ourselves (with a neutral external force or Leviathan). Darwin would say that ruthless competition has driven genetic change, but would never say that this ruthless competition was intrinsically good or should be encouraged. Rand, on the other hand, showed casual disregard for human suffering and would glorify in winner take all competition (even though that’s not how societies best organize themselves nor how evolution plays out in the real world where cooperation is usually a winning strategy)