In the mid 1970s there were around 200 sheep in the refuge;[3] however, in 1979, a scabies mite epizootic reduced the population from 200 to 75.[3] Subsequent years brought further declines from scabies and other causes until the population consisted of one ewe in 1997. Reintroduction of desert bighorn sheep occurred in 2002 and the herd has now about 80 members.[5]