Making a sweeping generalization suggesting no other living thing on the planet has a conscience is a fairly bold statement. I can point to the way some animals learn and change their behavior as an example of a form of conscience.
I agree with this. I also think that not everybody has a conscience...think sociopath. Lastly, I have known some animals to be kinder and more loving to their young (and any animal peers they have) than some humans I've known, as well as I've known animals to defend their young viciously. So I seriously concur with some animals having a type of inner moral compass, or a form of conscience.
WHAT? are you serious? Pretty much anything with enough higher brain capacity to have a social structure has some sort of psychology similar to a conscience.
The word conscience means con/with, science, from Latin scientia, meaning "knowledge". Why are we with knowledge? Perhaps because want to know. We come to this world seeking initially curious about light, then wondering where the food at and at some point wonder hey babe wanna get together leading to let's say the carnal estate.
Some people I wonder....and feel.... and my favorite line is straight from my mom's mouth.....one of her great quotes.... "If they had a conscience, it would bother them...."