A feeding trip?

Most Australian Fur Seals undertake their feeding dives during the day when it is light. While others do most of their feeding at night, and some don’t seem to mind if it is day or night.

Below is a graph of one feeding trip by one seal, her name is Cassie. The scale on the side of the graph shows how deep the dives were and the scale at the bottom shows the number of days. Her trip lasted seven days. In the graph, each black line represents one dive. So most of her dives went below 50 m and her deepest dives went to about 100 m.

The wavy green line indicates light level. When the green line was up it was day time, when it was down it was night time. The purple line is temperature, which we wont worry about here.

Cassie undertook most of her diving when the green line was up. This means she was feeding mostly during the day time. She did some night time diving as well, but at night she mostly stayed near the surface. She was possibly trying to rest at these times.