Now, I had read Psalm 36 many, many times and had not picked up on the inclusion of animals. Then I read John H. Hayes' contribution to Preaching Through the Christian Year C.
What may initially strike us as odd in such a comparison or classification might not appear so if we give it some thought. The beast receives its blessings, its food, its livelihood witout setting out to please God or anybody; it makes no effort to measure up to any standard; it simply drinks in the benfits that come its way from the created order controlled by God. The writer is suggesting something similar is the case with humans.
Lectio Divina: Psalm 36:9