1986
Blue whales have been recorded making 180 ° rolls during lunge-feeding , allowing them to engulf krill patches while inverted ; and they rolled while searching for prey between lunges , which has been hypothesized as allowing them to visually process the prey field to find the densest prey patches .
 animal: krill
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
Answer:
 animal: krill