A reliable method for sexing giant otters (Pteronura brasiliensis) in the wild
Keywords:Giant Otter, Pteronura brasiliensis, Sexing, Gender
Sexing of giant otters under field conditions is only possible when individuals are entirely out of the water, usually when basking or grooming. Body size is not indicative of gender, and the breeding pair does not necessarily consist of the largest animals in the group. Sexing is facilitated by the presence, in adult, parous females, of four permanently elongated teats (due to repeated and prolonged lactation) and, in mature males, of a visible scrotum. Identification of the breeding male is sometimes assisted his behaviour, specifically that of marking, and by his year-on-year permanence in the group. However, sexing is more difficult in adult females that have not lactated, or in sub-adults, juveniles, and cubs of both sexes. Here, we present a reliable method of sexing wild Giant otters of all ages and sexual status, tested with known sex individuals.
Carter, S.K. and Rosas, F.C.W. (1997) Biology and conservation of the giant otter Pteronura brasiliensis. Mammal Review 27: 1-26. http://dx.doi.org/10.1111/j.1365-2907.1997.tb00370.x
Duplaix, N. (1980) Observations of the ecology and behaviour of the giant river otter Pteronura brasiliensis in Suriname. Revue Écologique (Terre et Vie) 34: 495-620.
Groenendijk, J. and Hajek, F. (2006) Giants of the Madre de Dios. Ayuda para Vida Silvestre Amenazada – Sociedad Zoológica de Francfort, Peru. ISBN: 9972-2585-1-3. 160 pp.
Groenendijk, J., Hajek, F., Duplaix, N., Reuther, C., Van Damme, P., Schenck, C., Staib, E., Wallace, R., Waldemarin, H., Notin, R., Marmontel, M., Rosas, F., De Mattos, G.E., Evangelista, E., Utreras, V., Lasso, G., Jacques, H., Matos, K., Roopsind, I. and Botello, J.C. (2005) Surveying and Monitoring Distribution and Population Trends of the Giant Otter (Pteronura brasiliensis) – Guidelines for a Standardisation of Survey Methods as Recommended by the Giant Otter Section of the IUCN/SSC Otter Specialist Group. Habitat 16: 1-100.
Kalpers, J., Williamson, E.A., Robbins, M.M., McNeilage, A., Nzamurambaho, A., Lola, N. and Mugiri, G. (2003) Gorillas in the crossfire: population dynamics of the Virunga mountain gorillas over the past three decades. Oryx 37(3): 326-337. http://dx.doi.org/10.1017/S0030605303000589
Kelly, M.T., Laurenson, M.K., FitzGibbon, C.D., Collins, D.A., Durant, S.M., Frame, G.W., Bertram, B.C. and Caro, T.M. (1998) Demography of the Serengeti cheetah (Acinonyx jubatus) population: the first 25 years. Journal of Zoology 244(4): 437-488. http://dx.doi.org/10.1111/j.1469-7998.1998.tb00053.x
Rosas, F.C.W., Da Rocha, C.S., De Mattos, G.E. and Lazzarini, S.M. (2009) Body weight-length relationships in giant otters (Pteronura brasiliensis) (Carnivora, Mustelidae). Brazilian Archives of Biology and Technology 52: 587-591. http://dx.doi.org/10.1590/S1516-89132009000300010
Schenck, C. (1999) Lobo de Río (Pteronura brasiliensis) – Presencia, uso del hábitat y protección en el Perú. GTZ / INRENA, Lima, Peru; 176 pp. Spanish translation of German Ph.D. Thesis: Vorkommen, Habitatnutzung und Schutz des Riesenotters (Pteronura brasiliensis) in Peru (1996), Munich.
Schenck, C., Groenendijk, J., Hajek, F., Staib, E. and Frank, K. (2003) Giant Otters in the Peruvian Rainforest: Linking Protected Area Conditions to Species Needs. Pages 341-357 in Bissonette, J.A. and Storch, I. (Eds) Landscape Ecology and Resource Management – Linking Theory with Practice. Island Press, Washington, USA.
Staib, E. (2005) Eco-Etología del Lobo de Río (Pteronura brasiliensis)en el Sureste del Perú. Spanish translation of German Ph.D. Thesis. Ayuda para Vida Silvestre Amenazada – Sociedad Zoológica de Francfort Perú, Lima, Peru. 195 pp.
Sykes-Gatz, S. (2004) International Giant Otter Studbook Husbandry and Management Information and Guidelines (2005). Husbandry and Management of the Giant Otter (Pteronura brasiliensis). 2.ed. Zoologischer Garten Dortmund, Dortmund, Germany.
LicenseAuthors who publish with this journal agree to the following terms:
- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).