436
At the same time that in the core area, the Abrolhos Bank, male arenas would be
much more competitive, then causing younger males to move northwards and search
for new areas to aggregate, through singing, and then maximize mate.
Furthermore, reflecting on the multi faced hypothesis of a mating system, would
be important to analyze that the humpback whale population using the Brazilian
breeding ground have a sex-ratio of 1.2:1, similar to the expected rate of 1:1,
determined genetically by Cypriano-Souza et al. (2010). Baracho-Neto et al. (2012)
also support the site fidelity similarity between genders through a long term photoidentification study in Praia do Forte, same than the present study.
All these pieces together may help to create a scenario suggesting a mating system more complex than previously reported, with more fluidity of individuals,
females and males, along a broad area in the Brazilian coast and ideal breeding sites
possibly influenced by some environmental features as the extent of the continental
shelf, consequently depth gradient.
Furthermore, the diversity in singer male occurrence and behavior between different group compositions could be related to the complex communicative system
in humpback whales, as recently described by Freeberg et al. (2012). Future studies
should include environmental and whale occurrence data in a broader temporal
scale to test specifically each one of these factors and their influence in the acoustic
ecology and behavior of humpback whales.
15.5 Conclusions
This study contributed in the understanding of ecological mechanisms involved in
the humpback whale song behavior. In a social context, about one third of the sighted
groups presented at least one singer male, but also identifying groups with two to
four individuals, plus groups with female-calf pairs with one to two escort males.
The narrow continental shelf associated with the coastal distribution of the whales
in the study area may influence in the group compositions containing singer males.
We present an ecological perspective, including environmental features such as
depth, tides and moon, of the singing behavior in this species, and also show the
expansion of the acoustic activity, during the Brazilian breeding season.
References
Alcock J (1993) Animal behavior: an evolutionary approach. Sinauer Associates, Sunderland, 625 p
Andriolo A, Martins CCA, Engel MH, Pizzorno JLA, Más-Rosa S, Freitas A, Morete ME, Kinas
PG (2006) The first aerial survey to estimate abundance of humpback whale (Megaptera
novaeangliae) in the breeding ground off Brazil. J Cet Res Manag 8(3):307–311
Andriolo A, Kinas PG, Engel MH, Martins CCA, Rufino AM (2010) Humpback whale population
estimates and distribution along the Brazilian breeding ground. Endanger Spec Res 11:233–243
M.R. Rossi-Santos
At the same time that in the core area, the Abrolhos Bank, male arenas would be
much more competitive, then causing younger males to move northwards and search
for new areas to aggregate, through singing, and then maximize mate.
Furthermore, reflecting on the multi faced hypothesis of a mating system, would
be important to analyze that the humpback whale population using the Brazilian
breeding ground have a sex-ratio of 1.2:1, similar to the expected rate of 1:1,
determined genetically by Cypriano-Souza et al. (2010). Baracho-Neto et al. (2012)
also support the site fidelity similarity between genders through a long term photoidentification study in Praia do Forte, same than the present study.
All these pieces together may help to create a scenario suggesting a mating system more complex than previously reported, with more fluidity of individuals,
females and males, along a broad area in the Brazilian coast and ideal breeding sites
possibly influenced by some environmental features as the extent of the continental
shelf, consequently depth gradient.
Furthermore, the diversity in singer male occurrence and behavior between different group compositions could be related to the complex communicative system
in humpback whales, as recently described by Freeberg et al. (2012). Future studies
should include environmental and whale occurrence data in a broader temporal
scale to test specifically each one of these factors and their influence in the acoustic
ecology and behavior of humpback whales.
15.5 Conclusions
This study contributed in the understanding of ecological mechanisms involved in
the humpback whale song behavior. In a social context, about one third of the sighted
groups presented at least one singer male, but also identifying groups with two to
four individuals, plus groups with female-calf pairs with one to two escort males.
The narrow continental shelf associated with the coastal distribution of the whales
in the study area may influence in the group compositions containing singer males.
We present an ecological perspective, including environmental features such as
depth, tides and moon, of the singing behavior in this species, and also show the
expansion of the acoustic activity, during the Brazilian breeding season.
References
Alcock J (1993) Animal behavior: an evolutionary approach. Sinauer Associates, Sunderland, 625 p
Andriolo A, Martins CCA, Engel MH, Pizzorno JLA, Más-Rosa S, Freitas A, Morete ME, Kinas
PG (2006) The first aerial survey to estimate abundance of humpback whale (Megaptera
novaeangliae) in the breeding ground off Brazil. J Cet Res Manag 8(3):307–311
Andriolo A, Kinas PG, Engel MH, Martins CCA, Rufino AM (2010) Humpback whale population
estimates and distribution along the Brazilian breeding ground. Endanger Spec Res 11:233–243
M.R. Rossi-Santos