Why are some Animals born Blind?

Question

If an animal is born blind, is it because the animal is an offspring of a mother that gives birth to multiple offspring?
Which Genus/Species give birth to blind offspring? Do animals which give birth to Litters have more blind offspring?
Is Blindness at Birth a form of Genetic Preservation (IE: Survival of the Fittest)?

Answer 1

Animals that are born blind (with their eyes closed) like dogs,cats, mice, and many birds) are the animals that need to stay in the nest until they are more developed. Many of these animals will start walking around once their eyes open. The fact that their eyes are closed keeps them from leaving the nest.
A remarkable illustration of the difference between the infancies of two similar-looking animals is the rabbit and the hare. Rabbits are born hairless, with eyes and ears closed, totally helpless. They remain in a hidden nest; their mother leaves them to eat and drink, then returns to feed them. Hares are born with fur, and their eyes and ears are open. They can move about from the beginning, and are generally able to escape if frightened.
It would be difficult to frighten a newborn rabbit, as it is totally dependent on its mother for safety and care, and has no need for the fear instinct yet.
So yes, blindness at birth does serve to preserve the young who are dependent on their parents. If they could see, they would probably wander off. They generally start to do this as soon as their eyes open; while most animals born with their eyes open are able to move around as well.
Newborn humans are an interesting case. They are born helpless, and though their eyes can open at birth, they keep them shut most of the time. Apparently they have little need to see.

Answer 2

Because they don't need their eyes to "see". I know there is a type of mole that is blind and obviously you don't need eyes to dig. For what ever reason an animal has or doesn't have something there is always a reason. Mostly its survival.

Answer 3

I know of animals/fish born in caves without sight because they don´t need to have vision in their environment