From the ninth to the twelfth centuries, the Roman Catholic Church excommunicated almost every type of animal. In 1225, eels were booted out of the church. In 1386, at Falaise, France, a sow was expelled, and in 1389, at Dijon, a horse was ostracized. An ox was banished in 1405. Rats and bloodsuckers were ousted at Bern, Switzerland, in 1451. In Delemont, in 1906, a Swiss dog was one of the last animals to be excommunicated.
Source:
Stephens, John Richard. “Ignorance and Intelligence.” Weird History 101: Tales of Intrigue, Mayhem, and Outrageous Behavior. New York: Barnes & Noble, 2006. 118. Print.
At least they never excommunicated the platypus