The loris, a captivating primate found across South and Southeast Asia, is unique as the world’s only known venomous primate. These arboreal mammals are recognized by their distinctive large eyes and nocturnal habits. Their intriguing biology makes them subjects of considerable interest.
Defining the Loris
Lorises are strepsirrhine primates belonging to the subfamily Lorisinae. They share ancestry with African pottos and angwantibos, and are distantly related to lemurs. Physically, lorises are characterized by short or absent tails, dense gray or brown fur, and large eyes, often encircled by dark patches. Their short index fingers assist in their slow movements through tree branches.
Approximately 11 recognized species are categorized into three main genera: Loris (slender lorises), Nycticebus (slow lorises), and Xanthonycticebus (pygmy slow lorises). Slender lorises typically measure 8 to 10 inches and weigh around half a pound. Slow lorises are more robust, ranging from 11 to 15 inches and weighing up to 4.6 pounds, with the Bengal slow loris being the largest.
Unique Adaptations and Behavior
Lorises are nocturnal and arboreal, moving slowly and clinging to branches for extended periods. Their omnivorous diet primarily consists of insects, fruits, and tree saps or gums, though some species also consume small animals and vegetation.
Their venomous bite is a notable adaptation, unique to primates. The toxin originates from a brachial gland on their upper arm. When threatened, a loris licks this gland, mixing the secretion with saliva to activate the venom, delivered through specialized lower front teeth called a toothcomb. While it can cause painful swelling and anaphylactic shock in humans, its primary use is for defense against predators and in territorial disputes. Female lorises may also coat their young with this venom as a protective measure.
Habitat and Conservation Status
Lorises inhabit diverse environments across Southeast Asia, India, and Sri Lanka. Their preferred habitats include tropical rainforests, bamboo groves, and mangrove forests, though they can also be found in scrub forests and agricultural plantations.
All loris species face threats and are listed as vulnerable, endangered, or critically endangered. For instance, the Javan and Bangka slow lorises are critically endangered, while the Bengal, Sunda, Sumatran, and pygmy slow lorises are endangered. Primary pressures include habitat loss due to deforestation, forest fragmentation, and fires, along with the illegal wildlife trade.
Lorises and Human Interaction
Human interaction with lorises is often detrimental to them. The illegal wildlife trade is a major threat, as lorises are frequently targeted for the exotic pet trade, driven by their “cute” appearance and viral social media videos. They are also captured for traditional medicine and tourist photo opportunities.
Lorises are unsuitable as pets. Their nocturnal nature causes stress and discomfort in brightly lit environments. They require a specialized diet rarely met in captivity, leading to health issues like obesity, diabetes, and kidney failure. To prevent bites, traffickers often brutally remove their teeth without anesthesia, a procedure that often results in infection, pain, and death, making them unable to survive in the wild. Most lorises in the pet trade are poached from the wild, not bred in captivity.