The slow loris is a small, distinctive primate found exclusively in the forests of South and Southeast Asia. This nocturnal animal is known for its large eyes and deliberately slow movements as it navigates the high forest canopy. While they may appear gentle, this group of primates holds a unique distinction, possessing a specialized defense mechanism unlike any other primate species.
Identification and Natural Habitat
Slow lorises belong to the Strepsirrhine suborder of primates, characterized by wet noses and a reliance on scent marking. There are several recognized species within the genus Nycticebus, all sharing a compact body plan and lacking a substantial tail. Their large, round eyes are an adaptation for hunting and moving in the low light of their nocturnal world.
They possess dense, woolly fur, a short snout, and typically range from 20 to 37 centimeters in body length. A dark stripe often runs down the animal’s back, contrasting with its lighter fur. These primates are native to a wide geographical range spanning from Northeast India, through Southeast Asia, and extending to the islands of the Philippines and Java. They spend nearly their entire lives in the dense canopy of tropical and subtropical forests.
The Unique Venom
The slow loris produces a potent toxin, making it the only known venomous primate. The defense mechanism involves a specialized patch of tissue called the brachial gland, located on the inside of its elbows. This gland secretes an oil, known as the brachial gland exudate, which the loris licks and mixes with its saliva.
The resulting complex venom is delivered through a bite using a specialized set of lower front teeth called a toothcomb. The brachial gland exudate contains a protein that is a variant of the Fel D-1 protein, commonly known as the major cat allergen in humans. This protein contributes to the venom’s toxicity, which is used primarily for defense against predators and in aggressive encounters with other slow lorises.
When threatened, a loris raises its arms above its head to access the gland, creating a defensive posture while preparing to bite. The animal also smears the venom onto its fur, particularly on infants, to protect them. For humans, a slow loris bite can result in immediate, intense pain and swelling. In rare cases, the venom can trigger a severe allergic reaction, including anaphylactic shock.
Behavior and Diet
The slow loris is strictly nocturnal, beginning activity around sunset and spending its days curled up asleep in tree hollows or dense vegetation. Their movement is a characteristic form of slow, deliberate quadrupedal locomotion, keeping three of their four limbs in contact with a branch at all times. This cautious movement helps them conserve energy and allows them to move silently when hunting or avoiding detection.
A specialized network of blood vessels in their hands and feet allows them to maintain a strong grip and cling to branches for extended periods without fatigue. The loris has an omnivorous diet that consistently includes tree gum, or sap, which they gouge from bark using their toothcomb. Their diet is supplemented with nectar, fruits, and small animal prey, such as insects and occasionally small vertebrates.
Conservation Status
All slow loris species face severe threats and are categorized by the International Union for Conservation of Nature (IUCN) as either “Vulnerable” or “Endangered.” A significant factor in their decline is the rapid loss and fragmentation of their forest habitat due to deforestation and the expansion of agriculture. Their reliance on the forest canopy makes them acutely vulnerable to these changes, as they are unable to travel long distances across the ground.
The primary threat stems from the illegal wildlife trade, driven by demand for the exotic pet market and traditional medicine. The loris’s large eyes and seemingly docile nature have made them popular in the illegal pet trade, especially through social media. To prevent the animal from inflicting its venomous bite, traffickers cruelly remove the loris’s teeth, often using crude tools without anesthesia.
This brutal procedure frequently results in severe infection, pain, and death due to blood loss or sepsis, contributing to the high mortality rate of captured animals. Those that survive the tooth removal cannot be returned to the wild, as they are unable to feed or defend themselves. Because of these threats, all slow loris species are listed in CITES Appendix I, which prohibits all international commercial trade.