A ground squirrel will sacrifice itself to an eagle to save other ground squirrels. But, this is more likely to happen when:
a. The nearby ground squirrels push the first ground squifrel into the open for the eagle
b. The nearby ground squirrels are cousins of the first ground squirrel
c. The nearby ground squirrels have a quick escape route
d. The nearby ground squirrels are siblings of the first ground squirrel