65365
William H. Calvin has suggested that some hand axes could have served as " killer Frisbees " meant to be thrown at a herd of animals at a waterhole so as to stun one of them .
 William H. Calvin
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
Answer:
 William H. Calvin