Why are there no Penguins in North Pole?

 We always see penguins only in South Pole but not in North Pole, though both of the pole's geographical conditions are same. 

Ever wondered why ???

Penguins are evolved to breed , nest , incubate and raise their chicks at ground level. 

Penguins are flightless birds and if they are in north pole , they are easily vulnerable to foxes , wolves , Polar Bears found in North Pole.

But humans tried to bring Penguins to North Pole from South Pole but penguins are short lived in north pole . No one knows the reason why .

But some theory states that penguins have failed to reproduce in environment of North Pole . Maybe they have fallen prey to land predators as they are flightless birds.