Primate Factsheets: Dusky titi (Callicebus moloch)
COMMUNICATION
Titi communication has been studied both in captivity and in the wild. Their characteristic
complex vocal behavior has been well documented (e.g. Moynihan 1966; Robinson 1977; 1979b;
Müller 1995; Müller & Anzenberger 2002) and has been said to represent, "the maximum elaboration
and complexity which can be attained by a species specific...language" (Moynihan 1966:125).
Their large repertory of vocalizations can be broadly classified into two types; high-pitched
quiet calls and low-pitched loud calls (Robinson 1977; 1979b). Most loud and quiet vocalizations
are repeated to form phrases and combined into long or short sequences that are used in different
contexts (Robinson 1979b).
Quiet, higher-pitched calls include "squeaks," "whistles," "trills," "chirps," "grunts," "sneezes,"
and distress calls uttered by infants (Robinson 1977). Higher-pitched calls are arranged along a
continuum by type and are not necessarily completely distinct from one another at a discrete point
(Moynihan 1966). Most of these calls are uttered when disturbed, both mildy and significantly.
However, some quiet calls are elicited before and after group calling, while foraging, or when
locating other individuals of the group (Moynihan 1966; Robinson 1977). Specifically, "chirps"
occur while foraging (Robinson 1977; 1979). "Whistles", "squeaks", "sneezes", and "trills" are
presumably uttered in the context of violence or hostility, or in inter- and intra-group conflicts
(Moynihan 1966; Robinson 1977). "Whistles" can also be heard during vigorous social grooming bouts,
vigorous play wrestling, when females resist unwelcome copulation attempts, or when an individual
is lost (Moynihan 1966).
Loud calls include "chirrups", "moans", "pants", "honks", "bellows", "pumps", and "screams", and are
both used in intra- and inter-group long range signaling. "Chirrups", which have been suggested to
contain information on the age and sex of the emitter, are produced in both hostile and non-hostile
situations, such as locating and recognizing group members, and probably fosters group cohesion
(Moynihan 1966; Robinson 1979b). "Moans" can be also heard in a combination of both hostile and
non-hostile circumstances, including during copulation and in greeting or when sympatric primates
pass through the titi's immediate area (Moynihan 1966; Robinson 1979b). Tooth "gnashing" represents
another form of audible communication, and while not vocal, is associated with "moan" vocalizations
and is performed in many of the same circumstances (Moynihan 1966). Screams are uttered in the
context of violence, conflict or hostility, as during fighting between young males (Robinson 1979).
Callicebus cupreus
Photo: Gustl Anzenberger
A key feature of the vocal communication of the titi monkey is the ritualized bout of morning
calling and duetting which helps regulate the spacing of groups and their home ranges (Robinson
1981). Duets are long sequences of loud calls that include "chirrups", "grunts", "moans",
"pants", "honks", "bellows", and "pumps." Males start vocalizing "moans" which lead on to male
"bellows" at the boundary of the group's home range and if a neighboring group approaches, both
the female and male will begin duetting in close proximity to one another (Robinson 1977; 1981;
Müller & Anzenberger 2002). Their calls in the duets are not synchronous and both sexes are
capable of producing the same types of vocalizations including both "bellows-and-pumping" and
"pant-and-pumping" (Müller 1995; Müller & Anzenberger 2002). These calls also tend to provoke
quick responses from other groups of titi monkeys and often begin with "moans" and quickly
increase in intensity, lasting up to and longer than five minutes (Moynihan 1966; Mason 1966).
After the confrontational duetting bouts between groups, a characteristic "gobbling" or "pumping"
vocalization may be uttered and is echoed quickly by neighboring groups within earshot (Mason 1966).
|
