Bear, a narcoleptic dog who propelled sleep medicine forward and helped educate visitors about the sleep disorder, has died, reports KQED.

Affectionately called “Bearichon,” the Belgian schipperke was the last member of a storied pack of narcoleptic dogs, assembled by William Dement at the Stanford University Center for Sleep Sciences and Medicine in the 1970’s.

The pack ultimately helped researchers find the gene responsible for narcolepsy, a disease characterized by excessive daytime sleepiness, cataplexy (sudden sleep episodes after experiencing intense emotions) and REM sleep abnormalities.