Can you name an animal whose killing cannot be performed without spilling your own blood?

Using Only Five 5's and any mathematical operator make sum as 37

John has eleven friends. He has a bowl containing eleven apples. Now He wants to divide the eleven apples among his friends, in such a way that an apple should remain in his bowl.
How can He do it?

Move four matchsticks to the below square to form three squares?

I go up and I go down.
I go up towards the beautiful sky and down toward the green ground.
I am present tense.
I am past tense too
Children love me.

Who Am I?

In the city of Brain Teasers, 5% of people do not list their phone numbers. Now if we select random 100 people from the phone directory, then how many people selected will have unlisted phone numbers?

When it is alive we sing, when it is dead we clap our hands. What is it?

Irene killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

Can you count the number of squares in the given picture?

This is a classy optical illusion puzzle. What more you can find except bricks in the image below?