The intangible Soul...
If it can be said that humans have a Soul, then indeed that is a quality which ALL living things possess.
It is simply not true that having a Soul in some way requires "intelligence" (however that may be measured or defined) or some other uniquely "human" factor. Perhaps people can not accept that other life forms, be they bugs or our next meal, might also have that thing which we call a "Soul".
Fact of the matter is that All living things have "it". We All "look out" through the eyes of the physical form we have and perceive the world to the best of our physical abilities. That some life forms may have limited ability to perceive their existence, much less understand it, does not mean they have no Soul. Nor does that necessarily imply you should not eat other living things... but it Does deserve more thought and even "thanks" to those that perish before us... or For us.