Journal of Threatened
Taxa | www.threatenedtaxa.org | 26 December 2023 | 15(12): 24352–24356
ISSN 0974-7907
(Online) | ISSN 0974-7893 (Print)
https://doi.org/10.11609/jott.8505.15.12.24352-24356
#8505 | Received 04
May 2023 | Final received 06 November 2023 | Finally accepted 28 November 2023
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
Sreehari K. Mohan 1, Lathish R. Nath 2, K.S. Subin
3, Sreekumar K. Govindankutty 4 &
P.O. Nameer 5
1–5 Centre for Wildlife Studies,
College of Forestry, Kerala Agricultural University, Vellanikkara,
Thrissur, Kerala 680656, India.
1 Rebuild Kerala Development Programme, Forest Headquarters, Vazhuthakkad,
Thiruvananthapuram, Kerala 695014, India.
2 Government Vocational Higher
Secondary School Wadakkanchery, Thrissur,Kerala, 680582, India.
1 sreeharikmohan007@gmail.com, 2
lathishrnath@gmail.com, 3 subinmanakody@gmail.com, 4 sreenomad123@gmail.com,
5 nameer.po@kau.in (corresponding author)
Editor: Nicole Duplaix,
Oregon State University, Corvallis, USA. Date of publication: 26 December
2023 (online & print)
Citation: Mohan, S.K., L.R. Nath, K.S. Subin, S.K. Govindankutty & P.O. Nameer
(2023). 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. Journal of Threatened Taxa 15(12):
24352–24356. https://doi.org/10.11609/jott.8505.15.12.24352-24356
Copyright: © Mohan et al. 2023. Creative Commons Attribution 4.0 International License. JoTT allows
unrestricted use, reproduction, and distribution of this article in any medium
by providing adequate credit to the author(s) and the source of publication.
Funding: Kerala Agricultural University.
Competing interests: The authors declare no competing interests.
Author details: Sreehari K. Mohan is a wildlife biologist who completed Masters in Forestry with specialization in Wildlife Science, Kerala Agricultural University, Thrissur. His interest lies in studying the ecology of mammals, trees, and birds. He is the co-founder of ‘Myristika’ that aims to promote nature education and sustainable resource sharing. He currently works as Project Manager of Rebuild Kerala Development Programme, Kerala Forest Department, Thiruvananthapuram. Lathish R. Nath is a passionate teacher with fervent enthusiasm for birdwatching, wildlife photography, and curiosity to explore the wonders of nature. Beyond the classroom, he proudly serves as a contributor for travel magazines, sharing compelling articles focused on birds. Subin, K.S. is a wildlife enthusiast who enjoys studying birds, mammals, and odonates. His interest goes beyond observation, as he actively contributes to conservation efforts and engages in citizen science projects to gather data on these creatures, emphasizing the importance of preserving their habitats. Sreekumar K. Govindankutty is not just a businessman; he finds solace and inspiration in birdwatching and bird photography. His curious and nature-loving spirit drives him to explore the wonders of the natural world, blending his entrepreneurial pursuits with a deep appreciation for the beauty and diversity of birds. P.O. Nameer is a professor of Wildlife Science at Kerala Agricultural University. He is a passionate researcher and academician with a keen interest in documenting biodiversity and strives to understand the ecology and biogeography of various taxa and communities, mainly in the Western Ghats region, with a motive to assist with the long-term conservation of the species and the habitats. He is also interested in the socio-economic dimensions of ecology.
Author contributions: SKM—field observation and data collection, manuscript writing, proof reading and referencing. LRN—field observation and data collection. KSS—field observation and data collection. SKG—field observation and data collection. PON—manuscript
writing, editing, proof reading and referencing.
Acknowledgements: We thank the Chief Wildlife Warden, Kerala
Forest Department, for the study permit (BDC1-15371/2018). We thank the
Wildlife Warden, Munnar WL Division, Divisional Forest Officer, Marayoor, Range Forest Officer, Marayoor,
Assistant Wildlife Warden, Chinnar for the logistical
support that enabled us to conduct hassle-free fieldwork in the remote forests
of the sanctuary. We would like to extend our gratitude to the dedicated team
of forest watchers who accompanied us throughout the trek, without whom the
collection of data and observations would not have been possible. The critical
reviews provided by the reviewers have been of immense help in improving the
quality of the manuscript, and we are grateful to the reviewers.
Abstract: 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.
Keywords: Chinnar,
conservation, small carnivores, montane forest, population decline, shola
forests, riparian forests, Small-clawed Otter.
Eurasian
Otter Lutra lutra
has been described as having one of the widest distributions of all
Palearctic mammals (Conroy et al. 1998). They are opportunistic and
have high foraging plasticity (Smiroldo et al. 2009)
and their diets are mainly composed of aquatic invertebrates, crabs, fishes,
and tetrapods (Almeida et al. 2012). In India, the
species is restricted to the Himalayan foothills up to Sikkim, north of the
Ganges, Assam in the north-east and to southern India (Wroughton
1920; Pocock 1941). They are considered to be absent from central India until
photographic records appeared from Madhya Pradesh and Chhattisgarh (Joshi et
al. 2016; Suraj et al. 2022). Despite extensive research on otters in the
Western Ghats (Basnet et al. 2020), including many recent sightings and
observations of Smooth-coated and Small-clawed Otters, there was no documented
evidence, such as photographs or genetic studies, of Eurasian Otters in the
region until recently. This could probably be because of the shy, often
nocturnal and elusive habit of the Eurasian Otters, making it difficult to
study in the wild by direct observations. Historical records indicate that
Eurasian Otters were previously documented in the Coorg hills of Karnataka, Ooty in the Nilgiris, Palani
hills, Pambar river in Kodaikanal,
Tamil Nadu within the Western Ghats (Ryley 1913; Wroughton
& Davidson 1920; Lindsay 1926; Pocock 1941; Prater 1971). Blanford (1888) examined a specimen that came from
Pondicherry, southern India while Lutra indica Gray was originally described from Madras
(Hinton & Fry 1923). Museum specimens in the British Museum of Natural
History (BMNH) were misidentified in the past, making it extremely difficult to
identify the Lutra lutra
to the subspecies (Nicole Duplaix in litt. September, 2023). Molecular
analysis has now made this straightforward, as evidenced by Mudappa
et al. (2018), who made a significant rediscovery of this species in the
Western Ghats, specifically in the Anamalai hills of
Tamil Nadu, after an absence of nearly seven decades. Their identification was
based on detailed morphological and molecular analyses of a carcass found as
roadkill.
Three
species of otters—Eurasian Lutra lutra, Smooth-coated Lutrogale
perspicillata and Asian Small-clawed Aonyx cinereus—are
known to occur in Western Ghats mountain ranges (Hussain 1999), Eurasian Otter
is mostly confined to small rivers in elevations ranging 450–950 m (Raha & Hussain 2016). The Smooth-coated Otter occurs in
large water bodies (Anoop & Hussain 2005). The Asian Small-clawed Otter is
the smallest of the otters and seems to prefer lower-order streams above 500 m
altitude in the Western Ghats (Perinchery et al.
2011; Mudappa et al. 2018).
Previous
records of Eurasian Otters in the Western Ghats were primarily based on surveys
that relied on identifying spraints and tracks, conducted by Raha & Hussain (2015) in five protected areas within
the southern Western Ghats. In their study, Eurasian Otters were identified in Periyar Tiger Reserve, Kerala based on track signs.
However, it is important to note that precisely distinguishing between
Smooth-coated Otters and Eurasian Otters based solely on tracks can be
challenging, and confirmation through camera trap images is recommended (Conroy
et al. 1998; Mudappa et al. 2018). This was further
validated by Nameer (2015) where Eurasian Otter was
not included in the checklist of mammals of Kerala. Some earlier studies
mistakenly identified Smooth-coated Otters as Eurasian Otters in the coastal
plains, leading to incorrect records of the species in peninsular India (Umapathy & Durairaj 1995; Umapathy 2000; Mudappa et al.
2018).
Previous
research concentrating on small carnivores within Western Ghats’ protected
areas consistently documented the presence of Asian Small-clawed Otters in Eravikulam National Park (Perinchery
et al. 2011; Nikhil & Nameer 2017), Silent Valley
National Park (Sanghamitra & Nameer
2018), and Wayanad Wildlife Sanctuary (Sreekumar & Nameer
2018); and despite extensive camera trap sampling, none of these studies
reported any Eurasian Otters in the region. However, in this paper, we present
a remarkable observation of live Eurasian Otters from Chinnar
Wildlife Sanctuary, southern Western Ghats of Kerala. This observation marks
the first-ever direct sighting of live Eurasian Otters in the Western Ghats
after an absence of nearly 70 years and represents an unmatched record for the
state of Kerala.
During the
‘Kerala Bird Atlas’ project (Praveen et al. 2022) fieldwork near Olikkudy (10.33180N, 77.14000E) in Chinnar Wildlife Sanctuary, Idukki district, Kerala, on 07
March 2020, at 1800 h we observed a remarkable behavior of Eurasian Otters in
the rocky-torrential streams of the Chinnar river.
Two otters, one female and one of unidentified sex, were actively searching for
food, demonstrating heightened activity among submerged rocks and crevices.
Their dives lasted between 5–20 seconds, and they exhibited a clear preference
for areas with strong water flow. While we did not witness them feeding above
the water’s surface, they consistently chewed on smaller prey-items after each
dive, suggesting they obtained their food directly from underwater. After
approximately 8–10 minutes of feeding, they left spraints on a nearby rock
(Image 1) before resting on another rock located about half a meter away. This
entire behavior was also captured on video (Video 1 & Video 2).
The
individuals were confirmed as Eurasian Otter Lutra
lutra after careful examination by the experts
from the IUCN Otter Specialist Group (Jason Palmer in litt.
September 2023; Nicole Duplaix in litt. September
2023; Anna Loy in
litt.
September 2023) and referring Hwang & Lariviere
(2005), Larivière & Jennings (2009), Hung &
Law (2016) and Menon (2023). The morphological features such as the flattened
head shape, nasal arrangement with double ridged rhinarium, webbed feet with
visible claws and structure of the tail are definite for Lutra
lutra. According to Larivière
& Jennings (2009) and Hung & Law (2016), the morphometric details are
as follows, head-to-body length: 50–82 cm, tail length: 33–50 cm, weight: 5–14
kg.
During the
sighting, the otters were spotted at an altitude of 1,275 m on the western
slopes of Chinnar Wildlife Sanctuary, amid wet
evergreen vegetation, transitional sholas, and riparian patches (Image 4). The
stream, ranging 0.2–1.2 m in depth, was nestled between two hill ranges adorned
with montane sub-tropical forests and grasslands. Riparian vegetation included
various tree species such as Elaeocarpus tuberculatus, Elaeocarpus munronii, Litsea spp., Acronychia pedunculata,
Actinodaphne spp., Meliosma
simplicifolia, Oreocnide integrifolia, and Schefflera
spp., along with dominant ferns of the Cyathea
genus. The swiftly flowing stream was characterized by boulders and fallen
trees (Image 4). Perinchery et al. (2011) noted this
habitat as suitable for Asian Small-clawed Otters, suggesting potential
resource partitioning between these two otter
species in the area. It is worth noting here that these observations are
counter-intuitive to the previously suggested idea by Raha
& Hussain (2015), where it has been claimed that the species prefers
moderate to slow-flowing rivers or dams in the Western Ghats. We could also
find multiple spraints of the otters upstream in the subsequent days. The
spraints dominated with finely macerated crabs, fishes and other fresh-water
crustaceans laid over rocks or sand bars.
The
Eurasian Otter has been listed in Appendix-I of CITES, Near Threatened as per
IUCN Red list of Threatened Species (Loy et al. 2022) and largely depleted as
per the IUCN Green status due to a decline in population (Loy et al. 2021).
Within the Western Ghats, there is a notable lack of data regarding both the
distribution and population status of the Eurasian Otter. Hung & Law (2016)
reports 12 subspecies of Lutra lutra and the subspecies seen in southern India is Lutra lutra nair. Phylogenetic studies are needed to find out
the exact taxonomic status of this otherwise wide-ranging species in the
Western Ghats.
Conserving
this otter species necessitates prioritizing efforts like preserving and
restoring riparian vegetation, and mitigating threats such as habitat loss,
sand mining, and hunting (Yoxon & Yoxon 2019; Basnet et al. 2020; Suraj et al. 2022). This
observation highlights the need for comprehensive research on Eurasian Otters
and other small carnivores in the Western Ghats, focusing on taxonomy,
distribution, population status, habitat characterization, resource
partitioning, and behavior. Such studies are integral to the conservation of
these lesser-known mammal species in the biodiverse Western Ghats region.
For figure
& images - - click here for full PDF
Video 1. Euresian Otter Lutra lutra actively foraging. © Sreehari
K Mohan.
Video 2.
Eurasian Otter Lutra lutra
depositing spraints. © Sreehari K Mohan
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