Nurse shark

Photo: Luis P. B. · CC BY-NC

Tawny nurse sharks rest motionless in aggregations under coral ledges at the deeper steps of Mpunguti ya Juu, their barbels probing the substrate even at rest. They are obligate suction feeders, capable of creating enormous negative pressure to extract crustaceans and molluscs from crevices. Unlike most sharks they can pump water over their gills without swimming, which is why they can rest on the bottom for hours.