IUCN/SSC Otter Specialist Group Bulletin
©IUCN/SCC Otter Specialist Group
Volume 38 Issue 1 (January 2021)
Abstracts
Outdoor Enclosure Use and Behaviour of Adult and Cub Asian Small Clawed Otters Aonyx cinereus in Summer and Winter
Pages 3 - 27 (Article)
Mirela Cuculescu-Santana, James Mason, Kristian Purchase, and Rhys Mckie
The behaviour and outdoor enclosure use of a family of Aonyx cinereus otters were investigated in summer and winter at the Wildfowl and Wetland Trust Washington center, UK. In summer, swimming and paddling (adults and cubs) and diving (adults) were recorded significantly more frequently than in winter, correlated with significantly higher frequencies of use of the water features. For the cubs, the relative frequency of diving was significantly lower compared to winter, as the cubs were still learning to swim and forage underwater. The levels of activity and the diversity of behaviours were higher around feeding times in both seasons. The cubs were already swimming in shallow water at 3.5 months-old and in deeper water at 4.5 months-old, mostly as a family group. At 3.5-6 months-old they were out of sight in the den significantly more frequently than the adults and displayed more play-fighting. By 8-9.5 months-old they moved around independently, foraging or playing and their behavioural budget was similar to that of the adults. Object juggling and vigilance standing were displayed from around 4 months-old, when weaning also occurred. The introduction of additional structural enrichment (logs, holt, nest-box) in early autumn increased the frequency of use of ground areas in winter, when the water temperatures were below 10 °C. The feeding and structural enrichment strategies used were effective for keeping the otters active outdoors and maintaining their high display value in the cold season (day time summer air temperatures 15-27 °C > winter 3.5-10 °C), emphasizing the importance of enrichment for good welfare.
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New Scent Marking Behavior of Neotropical Otter (Lontra longicaudis) in the Eastern Brazilian Amazon
Pages 28 - 37 (Report)
Fernanda Michalski, Cassiano Bueno Martins, Marcelo Lopes Rheingantz and Darren Norris
Scent marking behavior in mammals is related with both inter and intra-specific communication. Several otter species are known to communicate via scent marking, but a couple scent marking has not been documented in the Neotropical Otter (Lontra longicaudis). We obtained field observations of scent marking behavior in Neotropical Otters over two years using camera traps along waterways in the eastern Brazilian Amazon. Our results reveal the use of sandy substrates on islands and river margins for intra-specific communication between otters. Most records (62.5%) were from solitary adults. We document multiple independent records of adult otters digging to scent mark with urine and couple behavior of males urinating on top of female’s fresh urine in newly dug shallow craters. We also demonstrate behavioral plasticity of this species evidenced by camera traps recording terrestrial activity during both day and night. Our results contribute to improve the knowledge of the behavior of this otter species in the wild and can potentially be applied to improve ex-situ welfare of captive otters.
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Incidental Sightings of the Vulnerable Asian Small-Clawed Otter (Aonyx cinereus) in Assam, India: Current and Future Threats
Pages 38 - 44 (Short Communication)
Rohan K. Menzies And Megha Rao
The Asian Small-clawed Otter (Aonyx cinereus) is the smallest otter species in the world and is listed as Vulnerable due to the large number of threats they face, ranging from habitat loss to hunting. This report highlights the importance of Asian Small-clawed Otter habitats in Assam, India, through four incidental sightings; two with photographic records.
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Assessing the Occurrence and Resource Use Pattern of Smooth-Coated Otters Lutrogale Perspicillata Geoffroy (Carnivora, Mustelidae) in the Moyar River of the Western Ghats Biodiversity Hotspot
Pages 45 - 58 (Short Communication)
Kannadasan Narasimmarajan, Matt W. Hayward andManu Thomas Mathai
Understanding the factors affecting presence and habitat requirements of threatened species is fundamental to their conservation. Patterns of occurrence and resource use by the vulnerable Smooth-coated otter were examined by sampling Moyar River in the Western Ghats biodiversity hotspot of India between 2015 and 2017 for otter spraints, tracks, dens and grooming sites. An occurrence-based framework was used to determine the influence of environmental covariates on otter detectability. Information on environmental parameters was recorded every 400 meters along the riverbanks in post-monsoon, winter, and summer seasons. Smooth-coated otter occurrence was high before the summer but waned drastically after monsoon when increased water levels reduce detectability of otters by washing away signs of their presence. Otter occurrence and resource use patterns were influenced by river substrate, habitat characteristics, riverbank traits and forest types. Otters prefer wider rivers, but avoided rocky areas with shallow water. Resource use patterns were determined by habitat traits and disturbance in all three seasons. Various forms of disturbances adversely affected the otter occurrence. Restoration of degraded habitats is necessary to improve the long-term conservation prospects of otters. Regional otter conservation plans need to be species-specific to help maintain the ecological balance of Moyar River ecosystem.
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