The squid has two gills and the ink sac empties into the water. The gills are feathery structures that may be hidden and there are two on each side. The colossal squid has 2 large gills with 20-80 gill filaments on each side. Squids have 3 hearts, two of which are located at the base of each gill. They are used to pump blood to the gills. They also have the ability to obtain oxygen from the water through their gills.