“…Regular cathemeral activity, defined by significant amounts of activity during both the dark and light phases of the 24-hr cycle [Tattersall, 1987], has been described for Aotus azarae [Wright, 1989] and the lemur genera Eulemur [Tattersall & Sussman, 1975;Sussman & Tattersall, 1976;Tattersall, 1977Tattersall, , 1979Overdorff, 1988, Wilson et al, 1989Colquhoun, 1993Colquhoun, , 1998Overdorff & Rasmussen, 1995;Andrews & Birkinshaw, 1998;Birkinshaw & Colquhoun, 1998;Curtis et al, 1999;Donati et al, 1999;Rasmussen, 1999] and Hapalemur [Mutschler, 1999]. Observations of cathemeral activity in Hapalemur simus, Varecia variegata variegata [Wright, 1999] and the anthropoid Alouatta pigra [Dahl & Hemingway, 1988] were also reported.…”