When you walk along a long path, you often think. For instance, you know where you are coming from, but you ask where I am going, you think to conduct yourself through the paths under your feet the best possible way you can, you think and remind yourself of your purpose of being on that path, taking up that journey. You think of the length of the journey: how far you have come and how far is still there to go. Shall I continue, shall I sit down by the wayside and take some rest. While your head is busy thinking, vacillating, feeling hopeful or dependant, going up and down, the feet under you keep moving, one step after another, despite the trepidations of a loathing and questioning mind, with a hiatus, hesitation or break. What gets you there are your feet, what made you go there is the mind.
The animals are like the footprints of our evolutionary past. There they stand behind us on the evolutionary timeline, the way they almost always did. Once formed, however through millions of years of evolutionary process, animals are done forever.
Animals, therefore, are what they are, what they were and what they will always be, and the meaning of their life exactly the life they live: when hungry meanings is food, when thirsty it means water, when sleepy it is sleep and when in danger it is the escape, without a hesitation or thought. Since animals have their life so exactly natural, they do not need anything more meaningfulness.