Many years ago, I was lucky enough to find an old (copyright 1955)
book at a garage sale all about Exterminator. It's called "Old
Bones, the Wonder Horse" by Mildred Mastin Pace.
In it I learned all about Exterminator. His sire was McGee and his
dam was Fair Empress, by Jim Gore. He was actually bought as a
workout partner for another horse, Sun Briar, who was the "star" of
owner W.S. Kilmer's stable. Exterminator was a 3 year old unknown
gelding when he was bought 2 weeks before the 1918 Kentucky Derby.
Sun Briar didn't make it to the Derby but Exterminator did and won
as the longest shot in the race at 29-1!!!
Exterminator did not race undefeated, but he had quite a career. He
raced over 8 years, ran in 100 starts, and won 50 of them (was also
second or third in 34 more!). At the time, he was America's top
winner of cup races. He was retired in 1924 at the age of 9, when he
pulled up lame in his 100th race. He later died of a heart attack at
age 30. I hope this is of interest to you!
p.s. Aurora Borealis is a wonderful name for a racehorse!
David F. Adcock