Asian Small-clawed Otters Aonyx Cinereus Research Articles

Recent record of Eurasian Otter Lutra lutra (Linnaeus, 1758) (Mammalia: Carnivora: Mustellidae) from Kerala part of the Western Ghats, India and an insight into the behaviour and habitat preferences

We report a recent record of the elusive Eurasian Otter Lutra lutra from Kerala, through a direct observation in the higher reaches of the Chinnar Wildlife Sanctuary within the Western Ghats, southern India. Field observation involved the sighting of two Eurasian Otters in a rocky-torrential stream in March 2020. The otters displayed a hyperactive foraging behaviour, searching among submerged rocks and crevices, followed by occasional dives. They seemed particularly interested in areas where water rushed with force, avoiding locations with low water flow or shallow pools. The observation site, at 1,275 m altitude in Chinnar Wildlife Sanctuary, located in the Western Ghats of Kerala region, featured wet evergreen vegetation, transitional sholas (stunted evergreen forests), and riparian patches along a stream characterised by rapid water flow, boulders, and fallen trees. This habitat, as observed by others, was also indicative of Asian Small-clawed Otter Aonyx cinereus suitability, suggesting potential resource partitioning between the two otter species. This discovery challenges previous assumptions about the preferred habitat of Eurasian Otters in the Western Ghats and emphasizes the need for comprehensive research on the taxonomy, distribution, population status, and behaviour of these possibly sympatric species of otters, the Asian Small-clawed Otter and the Eurasian Otter. Such studies are crucial for the conservation of both these species, which face threats from habitat loss, sand mining, hunting, and population decline. Preserving and restoring riparian vegetation in the higher reaches of the Western Ghats is essential for their protection within this biodiversity hotspot.

Camera trap survey of mammals in Cleopatra’s Needle Critical Habitat in Puerto Princesa City, Palawan, Philippines

A camera trap survey was conducted in the recently protected Cleopatra’s Needle Critical Habitat (CNCH) in Puerto Princesa City, Palawan, Philippines from February to May 2015 at 39 camera trap sites. A bait of common pig’s blood was used at 36 sites, while the three remaining sites were surveyed without a bait and monitored a stream with a latrine site or mud bath with tracks. Seven native species were detected and three of these species were endemic to the island province. Species included: Common Palm Civet Paradoxurus philippinensis, Palawan Porcupine Hystrix pumila, Collared Mongoose Urva semitorquata, Palawan Stink Badger Mydaus marchei, Palawan Leopard Cat Prionailurus bengalensis heaneyi, Asian Small-clawed Otter Aonyx cinereus, and Malay Civet Viverra tangalunga. Analysis of the activity patterns of the three most commonly captured species revealed predominantly nocturnal activity for the Common Palm Civet, Palawan Porcupine, and Palawan Stink Badger. The Philippine Palm Civet showed occasional diurnal activity. The seven photo-captured species appeared most common, or were at the least recorded, below 750m. Five species (the Philippine Palm Civet, Palawan Porcupine, Collared Mongoose, Palawan Stink Badger, and Palawan Leopard Cat) were also recorded above 1000m. The CNCH supports two threatened species, the Palawan Porcupine and the Asian Small-clawed Otter, which are listed as Vulnerable by the IUCN, and the Collared Mongoose is listed as Near Threatened. The Palawan Leopard Cat is considered Vulnerable within the Philippines, although it has yet to be assessed by the IUCN. This documentation highlights the biodiversity significance within the newly protected critical habitat and the need to support ongoing conservation efforts within the critical habitat. 

Morphological and molecular characterization of Cystoisospora sp. from Asian small-clawed otters Aonyx cinereus.

In this study, we provide the first description of Cystoisospora infection in Asian small-clawed otters (Aonyx cinereus). In July 2017, three juvenile otters recently imported from the Republic of Indonesia showed severe diarrhea and were diagnosed with coccidial infection; two of them eventually died. Fecal examination revealed the presence of numerous oocysts. Sporulated oocysts showed typical Cystoisospora features, measuring 24.6 ± 1.6 (22.0–27.0) × 21.8 ± 1.4 (19.0–25.0) μm, with an oocyst length/width ratio of 1.1 ± 0.1 (1.0–1.3). Each sporocyst contained four sporozoites in a head-to-tail arrangement. The Stieda body was absent, and the sporocyst residuum was present. These morphological characteristics differentiated this species from the other valid Cystoisospora species described from mustelids. Molecular analysis was conducted at two loci: the nuclear 18S ribosomal RNA and mitochondrial cytochrome c oxidase subunit I genes. The 18S sequence showed high similarity with canine Cystoisispora ohioensis (1-bp difference, 1422/1423 [99.9%]). At the cytochrome c oxidase subunit I gene locus, the sequence from otters was identical to that of feline Cystoisospora rivolta (847/847 [100%]). Phylogenetic analyses using concatenated data demonstrated that Cystoisospora sp. from otters and C. rivolta grouped together in the same Cystoisospora clade. Based on these data, we concluded that Cystoisospora sp. detected from otters appeared to be highly similar to C. rivolta.

<b>Small carnivores of Wayanad Wildlife Sanctuary, the southern Western Ghats, India</b>

The small carnivores of Wayanad Wildlife Sanctuary were surveyed using camera traps. The study was conducted between November 2016 and February 2017 at 111 camera trap locations. Twenty-five mammal species were recorded, including nine small carnivores from the Mustelidae, Viverridae, Herpestidae and Felidae families. Species included the Asian Small-clawed Otter Aonyx cinereus, Brown Palm Civet Paradoxurus jerdoni, Common Palm Civet Paradoxurus hermaphroditus, Small Indian Civet Viverricula indica, Indian Grey Mongoose Herpestes edwardsii, Ruddy Mongoose Herpestes smithii, Stripe-necked Mongoose Herpestes vitticollis, Jungle Cat Felis chaus and Leopard Cat Prionailurus bengalensis. The most common small carnivore was Viverricula indica, followed by Herpestes vitticollis and Paradoxurus hermaphroditus. Time activity patterns revealed that the viverrids were nocturnal while the herpestids were diurnal. The sanctuary supports one endemic species of small carnivore, Paradoxurus jerdoni, and one threatened species, Aonyx cinereus, which is Vulnerable according to the IUCN Red List of Threatened Species. This documentation highlights the biodiversity significance of Wayanad Wildlife Sanctuary and the Nilgiri mountain range in the Western Ghats.

<b>Small carnivores of the montane forests of Eravikulam National Park in the Western Ghats, India</b>

The study of small carnivores of the montane forests of Eravikulam National Park in the southern Western Ghats, India recorded nine species of small carnivores using the camera trapping technique. These include three species of Mongoose (Herpestidae), two species each of lesser cats (Felidae) and civets (Viverridae), one species each of Otter and Marten (Mustelidae). They are Stripe-necked Mongoose Herpestes vitticollis, Brown Mongoose Herpestes fuscus, Indian Grey Mongoose Herpestes edwardsii, Jungle Cat Felis chaus, Leopard Cat Prionailurus bengalensis, Common Palm Civet Paradoxurus hermaphrodites, Small Indian Civet Viverricula indica, Asian Small-clawed Otter Aonyx cinereus, and Nilgiri Marten Martes gwatkinsii. It is interesting to note that the felines (lesser cats) are the more common small carnivores in the montane forests. Felis chaus was the most abundant small carnivore, which is followed by Prionailurus bengalensis and Herpestes vitticollis. Two species are Vulnerable as per the IUCN Red List, viz., Martes gwatkinsii and Aonyx cinereus.

Past and present: the status and distribution of otters (Carnivora: Lutrinae) in China

AbstractThree species of otters are known from China; the Eurasian otter Lutra lutra is widespread throughout the country and the smooth-coated Lutrogale perspicillata and Asian small-clawed otters Aonyx cinereus occur in tropical and subtropical regions. We summarize the past status and distribution of otters in China, and provide an update based on a literature review, interviews and field surveys. Otter populations have undergone a dramatic countrywide decline, and are extirpated over much of their former ranges. Relict populations persist, however, in well-protected nature reserves, in sparsely populated headwaters of the Qinghai–Tibetan Plateau, at remote sites along international borders, and in densely populated deltas and floodplains. Recent records were mostly of the Eurasian otter, and we could find no confirmed recent record of the smooth-coated otter. The otters that survive in certain well-protected sites could act as source populations for recolonization if adequate conservation interventions are implemented. Urgent, focused action is needed to protect the remaining populations, and to study the taxonomy and ecology of China's otters.