I couldn't tell you if ants are conscious.
However, my pet dog is fully aware that it exists. This is evident when it chases its tail, knows when to communicate that it wants to go outside, knows to obey commands, gets scared when I yell at it for spreading garbage all over the house, tucks its tail between its legs when it anticipates a rolled up news-paper, crawls up into my lap when it wants attention, etc, etc, etc.
Just because my pet does not ponder the origens of existance and the correlation between neural functions and consciousness... does not mean that she doesn't acknowledge her own physical existance; especialy when she's hungry and realizes that by interacting with other intelligent beings, a dish full of food may result as a consequence.
From this I will conclude that monkeys, dolphins, whales, and many other organisms who respond to stimuli requiring somewhat intelligent "decision making skills", are aware. They know they exist; whether they actauly wonder why they exist, is another question.
This brings me to an interesting question...
If I were born blind, deaf, mute, without taste or smell, and numb... but some doctors were obligated to keep my heart pumping... what would life be like? I have been relieved of all my sensory functions, therefore all I may be able to do is think, but about what exactly? I don't know color, voices, emotions of fear, stress, etc. What the heck is there left to sit and think about? Am I conscious? Am I aware that I exist?