IUCN/SSC Otter Specialist Group Bulletin
©IUCN/SCC Otter Specialist Group
Volume 42 Issue 4 (August 2025)
Abstracts
Hematological Profile of Neotropical Otters (Lontra longicaudis)
Pages 163 - 178 (Article)
Oldemar De Oliveira Carvalho-Junior, Pricila S. Esteves, and Marcelo Tosatti
This study aimed to establish reference values for the haematological profile of Lontra longicaudis maintained in captivity, contributing to clinical evaluation, health monitoring, and conservation strategies for this endangered species. Blood samples were collected from 18 individuals of varying ages (from pups to adults) and both sexes, allowing for an initial assessment of physiological variability. The results revealed mean erythrocyte counts of 6.30 million/μl, haematocrit of 51.94%, and haemoglobin concentration of 16.39 g/dl, all within expected ranges for wild carnivores. Haematometric indices indicated a normocytic and normochromic pattern across most individuals. Leukocyte counts averaged 5.91 x10³/μl, with neutrophils as the predominant cell type, suggesting a stable immune status in the majority of animals. However, some individuals exhibited notable deviations, such as Otter 14, which showed leucocytosis, neutrophilia, monocytosis, and eosinophilia, possibly indicating an inflammatory or infectious process. Platelet counts and total protein levels were generally within normal limits, though isolated cases of thrombocytosis and hypoalbuminemia were observed. These findings provide baseline data for future comparative studies between captive and free-ranging populations. Despite the limited sample size, this research fills a critical gap in the literature and supports the development of targeted health management protocols for Lontra longicaudis. The establishment of these reference values enhances the capacity for early disease detection, improves veterinary care, and strengthens conservation initiatives for this key aquatic species in neotropical ecosystems..
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First Video Evidence of Interaction Between Introduced American Mink (Neogale vison) and Endangered Native Southern River Otter (Lontra provocax)
Pages 179 - 185 (Report)
Gonzalo Medina-Vogel, Carla Soto-Ampuero, Nicole Delgado-Parada, Gabriela Molina-Maldonado, and Carlos Calvo-Mac
The introduction of the American mink (Neogale vison) in southern Chile is a significant concern for the conservation of the southern river otter (Lontra provocax), especially in Patagonia, where both species overlap. This study provides the first documentation of close interaction between the two species, recorded by camera traps in the locality of Tarahuín, Chonchi municipality, Chiloé Island, Chile (South America). The encounter was characterized by aggressive behavior at close range and for a brief period of time, which may facilitate the indirect transmission of pathogens such as canine distemper virus (CDV) and canine parvovirus (CPV), especially around a latrine shared by wild carnivores. These findings indicate that American mink could act as a bridge host between domestic dogs and otters, and underscore the need to implement conservation strategies to mitigate their ecological and health effects.
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Relative Abundance and Habitat Use of the Neotropical Otter (Lontra annectens) in the Cuichat River, Central México
Pages 186 - 193 (Report)
Paola Moreno Barrera, Osvaldo Eric Ramírez-Bravo, Pablo Hernandez-Romero, and Bernardo Garabana Quintana
The eastern-central region of Mexico has very few reports on the presence of the northern neotropical otter (Lontra annectens). In this work, we determined the relative abundance and habitat use of L. annectens in the Cuichat River in Cuetzalan, Puebla. We followed a 16 km river branch that we traveled once a month from September 2012 to February 2013. In each descent, we identified sites with otter presence, signs of presence such as feces, latrines, tracks, feeding places, and dens. We estimated the density of usage of latrines along the river. We analyzed seven habitat variables that were evaluated using a χ2 analysis for habitat use. We obtained 31 sites with otter presence, with a relative abundance of 0.32 otters/km. When anthropogenic activity was absent, we found that otters were more active and occupied more shelters regardless of whether the site presented steeper slopes or abundant tree cover. Knowing the variables preferred by otters will allow us to make informed decisions to generate conservation programs related to the species in the Cuichat River, which can be applied to other areas occupied by the species.
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