• the wolf -- and why wolves make good fathers and dogs don't
  
• the beaver, who encourages his young to cling to his tail as he navigates through ponds
  
• the sea horse, the only male animal that gives birth to its young
  
• the marmoset, the South American monkey who carries his babies for the first two years of their lives wherever he goes.
  

Masson also examines nature's worst fathers: lions, langurs, bears -- and humans. He shows that when a father does care for his young, as with the beaver, we immediately look for a biological and not an emotional explanation. But Masson demonstrates that for these animals, as with humans, fatherhood is a profound, all-encompassing experience.