Loris

Like all lorises, slow loris has a cute wide-eyed look, but it also has a venomous sting that can rot human flesh. 

CONSERVATION STATUS

The International Union for Conservation of Nature (IUCN) considers all loris species (except the gray slender loris) threatened. The conservation status of relatively common lorises is as follows:

• Loris lydekkerianus (Gray slender loris) — Near Threatened 
• Nycticebus coucang (Slow loris), Nycticebus bengalensis (Bengal slow loris), Loris tardigradus (Red slender loris), and Xanthonycticebus pygmaeus (Pygmy slow loris) — Endangered
• Nycetibus menagensis (Phillipine slow loris) — Vulnerable
• Nycticebus bancanus (Bangka slow loris) — Critically Endangered

Summary

Lorises are arboreal and nocturnal creatures with soft gray fur and prominent eyes encircled by dark patches. This group of small primates inhabit the Southern Asia area. There are ten different species of lorises which researchers divide into 3 genera. Lorises are adept at moving through trees. They often hang by the trees with their feet, freeing their hands to grasp food from the branches. The Javan slow loris found on the Indonesian island of Java is one of the only handful of venomous mammals. It has advanced specialized glands under its armpits that produce a toxic venom when mixed with saliva and deliver what is called a necrotic bite. The bite causes flesh to rot.

Loris Facts 

• The eyes of a loris are like binoculars. They have excellent vision coupled with a special reflective layer across the outside that makes them see clearly at night.
• Lorises sleep during the day and hunt at night.
• Their lifespan runs between 15 and 20 years.
• The loris walks on all four legs.
• Despite their fearsome reputation, not all species of lorises are venomous. Only slow lorises can secrete venom, and the venom is not toxic in all species. 

Scientific Name

Loris refers to any of the 10 species of short-tailed or tailless primates in the subfamily Lorisinae. They are native to the forests of south and southeast Asia. Their common name is from the old Dutch word “loeris” which means “clown.” Lorises belong to the Lorisidae family, in which there are more than 16 species divided into 5 genera. Lorises are close relatives of the Lemurs (family Lemuroidea). Some of the most notable genera in the subfamily Lorisinae include: 

• Loris lydekkerianus — Gray slender loris 
• Loris tardigradus — Red slender loris 
• Xanthonycticebus — Pygmy slow loris 
• Nycticebus — Slow loris 

Loris — Appearance & Behavior 

While there are many different species of lorises, they’re all quite similar in shape and size. They have round faces, large eyes, and colored patches of fur around their eyes. As opposed to monkeys and many other primates, they do not have long tails but short stubs that serve as tails. They have short legs in comparison to other primates. All have strong hands and toes. They move with slow and deliberate hand-over-hand movements. 

Lorises vary in size from one genus to the other. Slender lorises, for instance, are about 8–10 inches long and may weigh as much as 0.55 pounds. The slow lorises are more robust. They’re typically about 11–15 inches long. They may weigh as much as 2 pounds, with the Bengal slow loris weighing up to 4 pounds. 

Behavior 

If alarmed, lorises can move quickly, but they hardly jump or leap. Their vampire-looking teeth are filled with grooves and are very sharp. Lorises know how to use the sharpness of their teeth to their advantage. They bite extremely hard, whether biting into flesh, the bark of a tree, or even a bone.

While their social behavior ranges from species to species, all lorises are arboreal and spend most of their time in trees. Some species live in small groups but forage alone. Those that live together generally like to congregate during the day when they sleep. All species are nocturnal. Lorises do not like to be separated from their kin. In the wild, they live together in family units, where parents and older ones care for the young ones who stay in the care of their parents for at most three years.

One defensive feature of slender and slow lorises is to freeze when they’re in danger until the danger passes. If this doesn’t work, they will stare brazenly at the attacker and growl while oozing a foul, offensive stench from scent glands under their arms. Before going off to forage, mothers park their babies in trees, lick their brachial glands, and then groom their young so that the venom is transferred to the fur of their infants. This is a deterrent against predators like leopards and bears.

Loris — Habitat 

Each loris species has different preferences when it comes to choosing a habitat. However, tropical rainforests are a popular favorite due to the abundance of trees on which they live. Some species prefer areas with less rainfall. Lorises can also be found in agricultural regions like plantations. Slender lorises have been found in India and on the Island nation of Sri Lanka at 15 degrees latitude.

Lorises are well suited to exploring and exploiting different types of habitats. They are often found in low swampy areas, humid tropical rainforests, and drier areas like fairly deciduous forests. The Sunda slow loris inhabits Peninsular Malaysia and the Indonesian island of Sumatra. The Javan loris is limited to the Indonesian island of Java. During cold nights, pygmy slow lorises that inhabit Vietnam, Eastern Cambodia, and Yunnan, China, are capable of entering a state of inactivity known as torpor. In this state, they reduce metabolism and body temperature for days.

Loris — Threats and Predators

A loris is a predator itself, feeding on insects, small birds, and reptiles. However, their diet is more accurately described as omnivores since they eat eggs, fruits, nectar, gums, and vegetation. Some species are known to be venomous. This group of lorises uses their venom mostly for defense and internal fights over territory or mates. 

Humans are the biggest threat to the population of lorises. Even though it is illegal to capture, sell, or own a loris in all the countries where their population is prominent, they are still caught for their use in traditional Asian medicine and the pet trade. The trade of lorises involves pulling their teeth and subjecting them to critical situations that are cruel, unfair, and in violation of animal welfare. Many of them die while being transported. Besides humans, snakes, hawk-eagles, orangutans, cats, and sun bears are also major predators of the lorises. 

Loris — Reproduction, Babies, and Lifespan 

Breeding, gestation, and infant care range from species to species. Most species have a gestation period that is about six months long, and then they give birth to about one or two babies. A young female loris cannot breed until it is about two years old. For a slender loris, the reproductive behavior is quite different. 

The slender loris breeds all year round in captivity. Mating seasons find the female in estrus for 29-40 days. During mating, females tend to hang on a branch and support the male’s weight along with their own. Gestation ranges from 166 to 169 days for the slender loris. They have a higher percentage of twin births compared to other members of the subfamily.

Newborns are usually pink and furless at the time of their birth, and they cling to their mother’s fur until their infancy fades away. At 10 and 18 months, they reach sexual maturity, but this duration is much slower in males. Their lives span a total of 15 or even 25 years.

Loris — Population

Over the course of the last century, the population of the lorises has been on a steady decline, with as much as a 50% fall in population. Poaching for the exotic pet trade is among the main factors responsible for their sharp decline. Despite government protections guarding lorises, their population continues to drop because wildlife protection laws are weakly enforced locally. The highland slender loris has less than 2,500 individuals surviving across South Western and Central Sri Lanka. Their conservation status is critically endangered. Most of the other species are endangered or threatened. The gray slender loris is near threatened.

Related Animals 

• Lemur
• Tarsier
• Squirrel Monkey

1. Britannica, Available here: https://www.britannica.com/animal/loris-primate-subfamily
2. New England Primate Conservancy , Available here: https://neprimateconservancy.org/lorises
3. Science Direct / Primate Anatomy (Third Edition) / Friderun Ankel-Simons, Available here: https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/lorisidae
4. Active Wild, Available here: https://www.activewild.com/loris-facts-and-information-for-kids/