Blood relatives are married children are born with genetic disorders why?

[peter4]

When Blood relatives marry each other for 2 - 3 generations, the offsprings are often born with genetic disorders. Why this is not happening in pack animals such as Cheetah, Lions, Wolfs etc. where offsprings are often born out of brother & sisters, mother & son, father and daughter?

 

[Asguard]

they often are, except that the offspring normally die before breeding unlike with humans. Look at the cheetah population, all the remaining members ARE blood relitives.

 

[Fraggle Rocker]

Humans go to great lengths to keep the weak and unhealthy alive. It's one of the things that defines our humanity.

Other animals let them die. Carnivores will eat their own offspring if they sense something wrong with them. This is an effective way to clean up the gene pool.