In almost all layers arthropods are the most abundant and diverse group of fossils in the GPB, followed by sponges.[1] 69.2% of GPB individuals and 63.9% of species lived on the surface of the sea bed; within this group, mobile deposit feeders that extracted food particles from the sediment accounted for 38.2% of the total number of individuals and 16.8% of the total species; the smallest sub-group was mobile hunters and scavengers; and the rest were sessile suspension feeders.[13] Animals that lived in the sediment made up 12.7% of the species and 7.4% of the individuals; the largest sub-group was mobile hunters and scavengers.