Jan 03 2022. views 44
As dusk set in at Sigiriya, a naturalist and team of guests got ready for their nature trail. A head torch with a red light, boots to keep the leeches away and extra torches to be used if the need arose were all that we had to take. We stepped into the terrain seldom frequented by humans and followed the naturalist, focusing the red light on treetops, bush-like trees, and almost every tree possible. Every false alarm sent a gush of adrenaline and sometimes, we just stood still, waiting for what we wanted to see. After about a half hour’s walk into the thick jungles, the naturalist pointed out two tiny red eyes, reflecting the light from our torches, looking directly at us! Hence, the mission to spot the Grey Slender Loris was a success.
A threatened primate
The Grey Slender Loris is one of the five other primates found in Sri Lanka. A primate is any mammal of the biological order Primates, the group that includes all species related to lemurs, lorises, tarsiers, monkeys, and apes, with the latter category including humans. Non-human primates are found mostly in Central and South America, Africa, and South Asia.
What makes primates different from other mammals is that their brains are larger than that of other terrestrial animals. Primates have flat nails while all other animals have claws or hooves on their digits. Although some primates have claws they have a flat nail on their hallux. The eyes face forward in all primates so that the eye’s visual fields overlap.
Sri Lanka is home to five out of 625 recognized species of primates found across the globe. These include Toque Macaques, Gray or Hanuman Langurs, Purple-Faced Langur, Red Slender Loris, and Grey Slender Loris. However, all these primates are now listed as endangered in the IUCN Red List.
Spotting the Loris
Lorises are an evolutionary conservative group that represents the family of pre-monkeys (prosimians) from which other primates evolved. In Sri Lanka, they occur as two species along with subspecies.
Red Slender Loris (Loris tardigrades)
n Loris tardigradus tardigradus – found in the island’s southwest region, mainly in lowland forests
n Loris tardigradus nycticeboidese – found in the hill zone
Grey Slender Loris (Loris lydekkerianus)
n Loris lydekkerianus nordicus – found in the lowland dry-zone forest and scrub jungle of the North
n Loris lydekkerianus grandis – found in the Central hills
While there are 10 distinct species and more subspecies of Loris distributed in the tropical jungles of Sri Lanka, India, and other parts of South East Asia, many of them are similar in appearance.
The lifestyle of a Loris
Lorises prey on insects including ants, termites, or even arthropods such as beetles, mollusks, and spiders. Diet plays a key role in the population density of primates. Hence there’s a positive correlation between the density of Grey Slender Lorises and the density of insect populations. This shows that rather than travelling long distances to hunt for food, they nest or stay closer to areas with more insects.
Lorises are nocturnal and arboreal and their movements are slow, fluid, and silent. They spend their day foraging and travelling but most of the time they’re inactive. Research done on sleeping groups of Lorises suggests that they live in multi-male social systems. Therefore more than one male is present in each group. Hence, a group is made up of about seven Lorises including offspring, at least one female, and at least a pair of adult males.
They socialize with repeated calls throughout the night. These calls range from steady-pitched ‘whoops’ to low-pitched ‘growls’. It is said that these calls are social in nature and are meant to gauge location and strengthen social bonds. Researchers suggest that their communications systems are intelligent and complex when analyzing vocalizations and specific meanings of certain calls.
Many nocturnal primates rely on olfactory senses and cues. According to researchers, the Grey Slender Loris uses brachial gland secretions to mark home territory and travel routes.
However, the Loris too has faced threats of extinction with habitat loss and fragmentation, encroachments for agriculture, setting up of power lines, and construction of highways. With habitat destruction, their habitats are cleared and therefore predators such as eagles could easily spot them. Apart from that Lorises are hunted for their meat and illegal pet trade and even for voodoo medicine where it is believed that Loris meat treats Leprosy and eye ailments. On the other hand, the use of pesticides in agriculture leads to a decline in insect populations which can result in the declining population density of Lorises.
Many of you may have wondered why we wore red lights during our trail. It is said the bright lights disturb their visual field and therefore Lorises tend to hide from sunlight and bright lights. With red lights, they could be spotted easily. Naturalists also advise wildlife photographers to refrain from using flash photography when capturing these tiny creatures in their habitats.
We spent some time trying to capture the Loris in the best angle, but it was too shy to pose for photographs. As the sound of crickets and an occasional nightjar blended into the soirée, we decided to leave their terrain, to let them enjoy their nightlife.