An alarm vocalization was identified in the pygmy rabbit. The call was composed of from one to seven syllables uttered in rapid succession. The syllables were complex tones with many overlying frequencies; the strongest occurred close to harmonic intervals at 4000 and 6000 Hz. In both laboratory and field conditions, the call seemed to be elicited by a potential predator and its use may be unique among leporids.
Green, Jeffrey S. and Flinders, Jerran T.
"Alarm call of the pygmy rabbit (Brachylagus idahoensis),"
Great Basin Naturalist: Vol. 41
, Article 9.
Available at: http://scholarsarchive.byu.edu/gbn/vol41/iss1/9