Warren was born in 1860 in
Waltham,
Massachusetts where attended
Massachusetts Institute of Technology from which he got his bachelor's degree in 1881. He got his second bachelor's degree in 1883 from the
Colorado College where, by 1902, he became full-time naturalist. He was recognised in 1909 for his contributions to
Colorado natural history and was made an honorary director of the
Colorado College Museum. After it he wrote many books; one
Mammals of Colorado was published in 1910, the other
The Beaver: Its Work and Its Ways came out in 1927. He died in 1942. ==References==