The Collaborative International Dictionary of English v.0.48:

bush baby \bush baby\, bushbaby
\bush"ba*by\(b[.u]sh"b[=a]*b[y^]), n.
   1. any of several agile long-tailed nocturnal African
      lemurlike primates of the genus Galago with dense woolly
      fur and large eyes and ears; -- called also galago.
      [WordNet 1.5]

WordNet (r) 3.0 (2006):

bush baby
    n 1: agile long-tailed nocturnal African lemur with dense woolly
         fur and large eyes and ears [syn: galago, bushbaby,
         bush baby]