Iowa State University Veterinarian Records, RS 22/6/0/9, University Archives, Special Collections Department, Iowa State University, http://www.add.lib.iastate.edu/spcl/arch/rgrp/22-6-0-9.html
Today many species of animals are threatened or endangered. The primary threat to their numbers is loss of habitat in the face of a rapidly growing human population. No real wilderness areas remain. There are only islands of rainforest or grasslands surrounded by grazing pastures~ roads~ and cities. These isolated breeding populations face the deleterious effects of inbreeding. As popular public attractions, species of the family felidae have become a center point for promoting conservation efforts. There are thirty-seven species in the family felidae. Only the domestic cat is not threatened or endangered.
Wilwerding, Lee D. and Evans, Lawrence E.
"Assisted Reproduction in Captive Wild Felids,"
Iowa State University Veterinarian: Vol. 56
, Article 12.
Available at: https://lib.dr.iastate.edu/iowastate_veterinarian/vol56/iss2/12