71984
He studied the developmental and anatomical differences between different breeds of many domestic animals , became actively involved in fancy pigeon breeding , and experimented ( with the help of his son Francis ) on ways that plant seeds and animals might disperse across oceans to colonise distant islands .
 fancy pigeon, Francis
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:
 fancy pigeon, Francis