syntactical arrangements have been described, and current recordings probably do not exhaustively catalog regional repertoires. Asynchrony could
result from either genetic or acoustic isolation, and thus this hypothesis does
not discriminate between these two mechanisms. To our knowledge, no
direct tests of any hypotheses about song sharing or song changes have been
conducted. Direct tests are difficult to accomplish but would certainly be
worthwhile. Comparing available long-term data sets on a larger scale than
has been done in the past to determine to what extent regional repertoires
of elements and themes do overlap would be an interesting first step. More
direct tests of congruence between genetically defined populations and
dialect groups are possible and warranted. The function of dialects and song
sharing in humpbacks is completely unknown. Further playback studies to
investigate responses of male and female whales to their own and foreign
dialects could provide insight into why song sharing is favored and how it
occurs.
4.2.2. Primates—Tamarin Long Calls
Dialects have been studied in several species of tamarins in the genus
Saguinus. Tamarins are distributed throughout the neotropics (Kinzey
1997c) and live in small groups of multiple males and females (Garber et
al. 1993; Savage et al. 1996; Kinzey 1997c) that are not close relatives. The
dominant female gives birth to twins, which are cared for communally by
most adult males in a group (Sussman and Kinzey 1984). Group size correlates with offspring survival (Sussman and Garber 1987) and may reduce
care costs for individuals (Price 1992). Groups travel together through their
large home ranges (Kinzey 1997c) and feed primarily on widely dispersed
insects, fruit, nectar, and exudates from plants (Garber 1993). Home ranges
of tamarin groups overlap extensively, and this overlap centers around
primary food trees. Groups defend food sources aggressively against other
groups to obtain priority access (Garber 1988; Payne and Payne 1997) and
experience costs if such defense is unsuccessful (Pruetz and Garber 1991).
Group defense involves both vocal display and physical combat (Payne and
Payne 1997).
A primary vocalization involved in group defense and group cohesion is
the long call. Long calls are 1–2-sec series of frequency-modulated syllables
(Fig. 4.12). Calls differ among species and have been used to clarify phylogenetic relationships among tamarin species (Hodun et al. 1981; Kinzey
l997b) and the other members of the callitrichidae, including lion tamarins
and marmosets (Snowdon 1993). Long calls also differ between individuals
and sexes within a species (Snowdon and Hodun 1985; Maeda and
Masataka 1987). Although there is no evidence of call sharing among group
members, individuals do respond preferentially to long calls of their own
group mates (Snowdon and Hodun 1985), suggesting that they learn to recognize each other’s calls. Long calls are often given by animals separated
4. Comparative Vocal Learning
195
result from either genetic or acoustic isolation, and thus this hypothesis does
not discriminate between these two mechanisms. To our knowledge, no
direct tests of any hypotheses about song sharing or song changes have been
conducted. Direct tests are difficult to accomplish but would certainly be
worthwhile. Comparing available long-term data sets on a larger scale than
has been done in the past to determine to what extent regional repertoires
of elements and themes do overlap would be an interesting first step. More
direct tests of congruence between genetically defined populations and
dialect groups are possible and warranted. The function of dialects and song
sharing in humpbacks is completely unknown. Further playback studies to
investigate responses of male and female whales to their own and foreign
dialects could provide insight into why song sharing is favored and how it
occurs.
4.2.2. Primates—Tamarin Long Calls
Dialects have been studied in several species of tamarins in the genus
Saguinus. Tamarins are distributed throughout the neotropics (Kinzey
1997c) and live in small groups of multiple males and females (Garber et
al. 1993; Savage et al. 1996; Kinzey 1997c) that are not close relatives. The
dominant female gives birth to twins, which are cared for communally by
most adult males in a group (Sussman and Kinzey 1984). Group size correlates with offspring survival (Sussman and Garber 1987) and may reduce
care costs for individuals (Price 1992). Groups travel together through their
large home ranges (Kinzey 1997c) and feed primarily on widely dispersed
insects, fruit, nectar, and exudates from plants (Garber 1993). Home ranges
of tamarin groups overlap extensively, and this overlap centers around
primary food trees. Groups defend food sources aggressively against other
groups to obtain priority access (Garber 1988; Payne and Payne 1997) and
experience costs if such defense is unsuccessful (Pruetz and Garber 1991).
Group defense involves both vocal display and physical combat (Payne and
Payne 1997).
A primary vocalization involved in group defense and group cohesion is
the long call. Long calls are 1–2-sec series of frequency-modulated syllables
(Fig. 4.12). Calls differ among species and have been used to clarify phylogenetic relationships among tamarin species (Hodun et al. 1981; Kinzey
l997b) and the other members of the callitrichidae, including lion tamarins
and marmosets (Snowdon 1993). Long calls also differ between individuals
and sexes within a species (Snowdon and Hodun 1985; Maeda and
Masataka 1987). Although there is no evidence of call sharing among group
members, individuals do respond preferentially to long calls of their own
group mates (Snowdon and Hodun 1985), suggesting that they learn to recognize each other’s calls. Long calls are often given by animals separated
4. Comparative Vocal Learning
195