The Secret Lives of Otters
Otters play an integral role in preserving the integrity of aquatic, particularly riverine ecosystems, of which they form an essential part. Our contributor, a research scholar at the Wildlife Institute of India, has spent many moons observing these mammals at close quarters. She shares with us her learnings from the field about the behavioural ecologies, habitats requirements, and threats to the continued existence of otters, on the occasion of World Otter Day.
On a misty winter morning, a pair of pied kingfishers perched on a low-hanging Jamun branch, wait patiently for a catch. Not bothering the pair, I, along with my field assistants, move ahead with the task at hand – searching for otters in the rivers of Rajaji-Corbett landscape, nestled in the lap of Siwalik. We had taken only a few steps, when a couple of glimmering grey bodies, almost like moving boulders in appearance, caught our attention. It was a pod of Smooth-coated otters engaged in foraging. The serendipitous moment called for serious observation, as one does not come across these elusive and shy mustelids very often. Other than the Smooth-coated otter, India is also home to the Eurasian otter and Asian small-clawed otter. The three species occur sympatrically in some regions of Northeast India and the Western Ghats. While the Eurasian otter is mostly solitary, the Smooth-coated and Asian small-clawed otters are social animals, living in family groups comprising of an adult female and her offspring, often joined by the breeding male and siblings from the previous breeding season. The pod I observed consisted of four individuals, an adult male and female pair and two sub-adult males. The female had conspicuously swollen nipples, an indication that she was lactating and had suckling pups. The survey time also coincided with the breeding period of the species, ranging from August to December, thus corroborating my observation. Although moving in groups, hunting seemed to be more of an individual effort rather than a group task. Spending a few seconds, or sometimes up to a minute or two underwater, the otter emerged victorious with a catch in its mouth. One by one, all the pod members finished off their morning feast and gathered on the dry sandy bank for grooming. “The otter uses its back as the principal towel, and lies upon it while executing a series of vigorous, eel-like wriggles. In a surprisingly short space of time the otter is quite dry except for the last four inches of its tail” – an excerpt describing the grooming behaviour of otters penned down by Gavin Maxwell in his book, “The Ring of Bright Water”. Unaware of our presence, the otters continued their bouts of fishing and grooming for another half an hour and later swam downstream, probably to find other foraging spots.
A trio of Smooth-coated otters grooming on a sandy bank in the Palain river, Corbett National Park. Notice the flattened paddle-like tails, that otters use to propel themselves, for steering and maintaining balance while swimming.
The emerald waters of the Palain river, replete with a diverse array of fish species, deep pools, sandy and rocky banks, with adequate riparian vegetation and no human disturbance, provide the critical habitat components necessary for the survival of Smooth-coated otters. As a narrow-niche species residing along a narrow strip of the riparian zone, otters require large extents of interconnected networks of rivers with intact vegetation, which necessitates that conservation actions are directed towards maintaining the hydrological regime as well as the connectivity among rivers, streams, and riparian corridor. Another river, with abundant otter signs and sightings in the Corbett landscape, was the Mandal river. A network of streams, rivers, and rivulets spread across the Rajaji-Corbett landscape make it a stronghold of the Smooth-coated otter population. The river Kolhu, in Lansdowne Forest Division, a crucial wildlife corridor between Rajaji and Corbett National Parks, is an absolute “otter heaven”. Here, I witnessed multiple otter sightings and the sandy banks bore abundant pieces of otter evidence, including spraints (a name specific for otter scat), tracks and grooming signs.
Surveying the Khoh river, which runs parallel to the NH 534 Delhi-Kotdwar Highway, was an altogether different experience as at the first glance, it seems prone to disturbance and uninhabitable by the sensitive otters; however, at stretches where the river was inaccessible to humans and therefore the least disturbed, there were many signs, including active dens. Rocky stretches and vegetation cover serve as denning sites and escape cover for otters. At the slightest hint of disturbance, they scurry into the dense vegetation.
Crevices under rocks and tree roots, and holes dug up in clayey banks, at an elevated level from the shoreline are used by otters for denning, crucial for rearing pups and resting. Females usually have shorter home ranges than males, especially during the breeding season when travelling far away from the holts becomes energetically expensive and risky for females. Otters mark the entrances of dens by sprainting and a glandular secretion known as “anal jelly”. Sprainting is also used as an act of territory marking and a form of communicating with conspecifics. Several tracks going in and out also indicate the usage of dens. When disturbed, otters abandon their dens and search for safer locations. Tracking otter signs along the Kolhu river, I found that otters also shifted their denning sites during the winter season, when water levels dipped and shoals of fishes migrated upstream in search of pools. Post rains, when water level increased and fishes were abundant throughout the river, the old denning sites were again laden with otter signs.
Otters show site fidelity, i.e., they return to the same foraging and denning spots, of course, depending on the availability of resources, especially food. As apex carnivores of riverine ecosystems, otters are dependent on a well-stocked fish population, thereby serving as a crucial element in the food web, governing prey-predator dynamics. Opportunistic hunters, otters also consume secondary prey such as crabs, molluscs, birds, reptiles and amphibians, although fishes are their favourite. The fact that Kolhu, Palain, Mandal and Khoh (to some extent), offer such excellent habitats to otters can be attributed to a large extent of the rivers falling within the boundaries of protected areas, which has granted them some degree of protection and offer a safe recluse for otters. The forests from where these rivers and streams originate are the soul of the ecosystem. The intactness of these forests dictates the perennial nature of the water bodies and the survival of biodiversity and local communities dependent on them for fulfilling their water requirements.
The snow-fed Ganga was my next destination to look for otters. Walking downstream, I surveyed around 20km of the Ganga from the Rishikesh Barrage to the Bhimgoda Barrage. Traversing through the Rajaji National Park, the riverscape would occasionally greet us with a splash of activities – a herd of grazing Chital, and an occasional Sambar stag, striking an alert pose upon our intrusion. A Pallas’s fish eagle, hovering in the sky, would periodically dive in the swift waters, often rewarded with a silvery catch. After two days of intensive searching, I came across the first otter signs – a few pugmarks and some spraint, around 2km upstream of the Bhimgoda Barrage. The river here is wide with sand bars, dense bankside vegetation consisting of mixed grassland and deciduous forests – an ideal habitat for otters. In this zone, the otters were relatively safe thanks to the river falling within the ambit of the Rajaji National Park. The vegetation and sandbars provide refuge to the otters in the event of disturbance by straying humans, as only a few kilometres away from their habitat was the bustling city of Haridwar, teeming with people wishing to cleanse their sins by taking a dip in the holy waters, the same waters that serve as the source of sewers and effluents eliminated by the rapidly growing population. The scenario downstream of Bhimgoda Barrage appeared grim. The cascading turquoise waters, where once gharials, otters, and dolphins were plentiful, had transformed into a dry riverbed. Hydrological alterations caused by dams and barrages may push a well-functioning ecosystem to its ecological limits, the brunt of which is borne by both biodiversity and humans.
Both otters and their freshwater habitats are highly threatened. The Smooth-coated otter is a vulnerable species according to the IUCN Red List, undergoing a continuous declining population trend owing mostly to the loss and degradation of its habitat. Direct persecution and illegal trade for pelt and body parts are a serious threat to the survival of the species, that challenge the effectiveness of the existing protection measures. For the conservation of otters, it is pertinent that the riverine habitats they are dependent upon are prioritised for conservation. Also known as “Ambassadors of Wetlands”, otters may serve as a flagship species for riverine ecosystems, ensuring the protection of both the predator and its prey. The critical Rajaji-Corbett landscape is under tremendous pressure due to a surge in developmental activities that have jeopardized the connectivity of the forests. The linear nature of rivers and streams make them especially vulnerable to any disruption in their natural flow regime and pollution, the effects of which manifest across the entire ecosystem and are not restricted to the source area. The pollutant I came across most frequently was the pervasive plastic. The Ganga is infamous for being one of the major rivers responsible for 90% of the plastic pollution of our oceans. Improper waste management system, failure of policies and improper execution of river conservation initiatives, and the growing dependence of humans on riverine resources are pushing many rivers to the verge of ecological collapse. On top of the pre-existing hurdles in the path of conservation, the second wave of the Covid-19 pandemic has hit India the hardest. While hundreds of dead bodies wash ashore of the Ganga and its many tributaries, it is unfathomable how the decomposing bodies would affect the riverine biota and human population dependent on it for water usage for day-to-day activities.
The framework of protected areas in India is mainly centered around terrestrial ecosystems, and wetlands and rivers are seldom offered the status of a protected area, with a few exceptions like the Chambal National Sanctuary (Chambal river), Vikramshila Gangetic Dolphin Sanctuary (Ganga river), Tungabhadra Otter Conservation Reserve (Tungabhadra river), and a few others. One reason might be the massively interconnected network and hierarchical nature of these ecosystems making their inclusion into the protected area network cumbersome. While designing effective freshwater protected area networks, one needs to consider the lateral, longitudinal and groundwater connectivity of these ecosystems. There is an urgent need for effective policies based on sound ecological knowledge that also take human dependencies into account for the conservation and restoration of the ecological integrity of these fragile habitats. Declaration of community reserves, a grassroots-style conservation mechanism, might be a solution to the herculean task of protecting riverine ecosystems. The fact that people can conserve large tracts of pristine forests using traditional conservation techniques has long withstood the test of time, as exemplified by the communities of northeast India. For community reserves to be effective, it is understandable that the forest department and local communities need to work in synergy. If the people are ensured security, their collective actions will automatically help the cause of river conservation. For otters to survive in the Anthropocene – the age of humans, our rivers must survive too.
Image Credits (for all images): Sayanti Basak