SSH remote log-in without private key

[Joe San]

I used ssh-keygen to generate key value pairs, and uploaded the public key to the remote server to which I would log-on to. Now I moved the private key from the $HOME_FOLDER/.ssh/ to another location. Closed the terminal on my Mac and tried to re-login again. I was assuming that the log-in would fail because the private key is not to be found. But to my surprise it logged in successfully. Why is this?

[Joe San]

Is the log-in credentials checked every time I make an SSH connection? I'm getting a bit confused here. I deleted the private key id_rsa from my /home/user/.ssh/ folder, but still I'm able to ssh log-in to my remote machine. Why is this?

[Joe San]

I got to know why!

http://superuser.com/questions/245635/why-does-rsa-authentication-work-after-deleting-private-key

Did an ssh-add -L and I get to see the key which is added to the ssh agent running on my machine. Now I need to figure that out to not cache it and check for the private key everytime I ssh to my remote machine.