Bird watching in a tropical forest is a delightful and engaging activity, with something new and exciting to see at every step. At my field site, the Dehing Patkai Widlife Sanctuary in Upper Assam, I was always distracted with the many joyous birds around: the collective chaos of a mixed flock with brightly coloured, eye-catching minivets moving around like darts of fire; howling laughing-thrushes thronging the understorey; colourful broadbills and magpies throwing surprises in the deeper forest; flocks of brown hornbills following their leader with utmost discipline and their leader in turn squealing his orders; babblers deftly navigating bamboo clumps; scores of pigeons raiding fig trees; bulbuls feasting on tiny berries; and barbets delivering their solo riffs.
However, observing mammals is a different from bird watching. While the calls of the hoolock gibbon would echo through the valley, I didn’t see them very often in this forest. Their neighbour, the capped langur was spotted at select spots, often making acrobatic leaps. To follow them as they manoeuvre effortlessly through the canopy is an arduous task. I occasionally caught a pair of crab-eating mongooses or yellow-throated martens bounding away and I consider those very lucky days. And, I earnestly wished that I be spared encounters with elephants every time I was on foot inside the forest. Squirrels, however, are an exception. I consider them the mammalian supplement to the joy of bird watching!
The tropical forests of South Asia harbour the highest diversity of squirrels in the world, both diurnal tree squirrels and nocturnal flying squirrels. One particular genus, Callosciurus, meaning beautiful squirrels, is a species-rich group in the Indo-Malayan region. Northeast India is home to two such species, the Pallas’s squirrel and the hoary-bellied squirrel.
The Pallas’s squirrel or the red-bellied squirrel, Callosciurus erythraeus, is the quintessential arboreal small mammal, the most common squirrel of these forests. Looking very closely like the bark of a tree when viewed dorsally, and sporting underparts with various shades of red, it is usually mistaken for the orange-bellied squirrel, Dremomys lokriah. At first sight, the Pallas’s squirrel comes across as a completely ordinary, lacklustre animal. Give it a bit of time and attention, however, and it reveals itself to be very amusing; it’s a trickster, the perfect opportunist, and its adaptability as elastic as a rubber band.
Those who have seen dipterocarp seeds, like those of sal (Shorea robusta) with their typical ‘wings’, swirl by with the wind, always reminisce about the joy that the event brings with it. Having witnessed the event in my college campus during the monsoons, I always imagined the event to be grander at my field site, a dipterocarp dominated forest, where the hollong tree (Dipterocarpus macrocarpus), a much bigger cousin of the sal, made up most of the forest. I was absolutely delighted one day when from afar, I saw a pair of seed wings flying by. On closer examination, I realised they were stripped off and were falling devoid of the seed. As high as 35 m or so, sitting on an emergent hollong tree much above the canopy of the forest, was a pair of Pallas’s squirrels feeding on the seeds after stripping the wings off them.
It was quite a contrast with another image where I had seen the squirrel feeding on the dry and hardened seed of Terminalia bellirica, locally called bhomura. It must have procured the seed from the ground, as there were no fruits on the tree at that time. I also saw the squirrel climb down the main trunk onto the understorey several times. I realised that this species uses the entire vertical column to its advantage, chewing off bits and pieces of whatever is available, always working on a try and err basis, which was remarkable in terms of its adaptability. This is quite unlike other squirrels, such as the black giant squirrel (Ratufa bicolor) or the Indian giant squirrel (Ratufa indica) which are restricted to the canopy, or the red-cheeked squirrels of the genus Dremomys which are known to forage on the ground. The Pallas’s squirrel has an eclectic diet comprising of mainly fruits and seeds, also including a substantial proportion of bark, leaves and leaf-buds, flowers, and in all likelihood insects. Given its fleet-footed nature and its active foraging style, it continuously scans the bark while moving up or down the trunk or along branches. This may also explain its occasional associations with mixed flocks (foraging together with bird species).
Like other tree squirrels, the Pallas’s squirrel builds nests using twigs, leaves, and fine strips of bark accumulated after considerable effort. It does not specifically nest in large trees like the black giant squirrel. It also uses smaller trees, climbers, and may even use tree holes, for I sighted a pair emerging from one. This again shows how adaptable the species is, and this can be attributed to its favourable size. Being considerably smaller than the giant squirrel and weighing much less, it does manage to exploit the loopholes that exist in the laws of the jungle. These laws apply rather strictly to its larger counterparts.
Courting and breeding pairs were seen quite often, usually chasing one another. Sometimes they were also accompanied by other squirrels, possibly other males trying their luck. Occasionally, several individuals were seen foraging very close by. Solitary feeders were not uncommon either. The Pallas’s squirrel does not appear to be highly territorial. Its active foraging nature, involving a lot of search and travel may preclude territoriality. But it does indulge in a show of strength. After spending the early morning hours foraging, it stations itself on a branch and starts calling out continuously. Other squirrels close by respond to this call. This soon turns into a melee of several squirrels calling and responding and goes on for a while. This appears to be a passive-aggressive form of territorial defence, turning aggressive when one individual approaches another.
To be able to observe animals in their natural habitat and learn about their way of life is the basic aspiration of wildlife biologists. However, there are only a few mammals whose stories we can reveal quite easily, after walking down a trail and watching them closely with a pair of binoculars. The Pallas’s squirrel stands out beautifully in this aspect, revealing its secrets to those who seek them and winning them over.