The Only Poisonous Primate: Slow Loris Facts, Habitat, Diet & Dangerous Bite Explained

When we think of primates, gorillas and chimpanzees usually come to mind. However, the primate family is much more diverse—and one of its lesser-known members, the slow loris, stands out for a very peculiar reason: it’s the only known venomous primate in the world.

Is the slow loris dangerous? Where does it live? What does it eat? In this article, we’ll explore the physical characteristics, habitat, diet, and reproductive behavior of the slow loris, along with its venomous defense mechanism and why it’s endangered.

What Does a Slow Loris Look Like?

Physical Characteristics

• Body Size: Slow lorises are small primates, measuring between 26 and 38 cm in length.

• Head & Eyes: They have a round head, small ears, and large forward-facing eyes, adapted for night vision. Their eyes are surrounded by dark rings, giving them an adorable—but deceptive—look.

• Fur: Their dense coat ranges from white to brown, and coloration can vary between individuals.

• Limbs: They have equal-length forelimbs and hindlimbs, with opposable thumbs for gripping branches. Unlike monkeys, they cannot jump but climb slowly and carefully through trees.

• Tail: Short and barely visible.

Behavioral Traits

• Nocturnal: Slow lorises are night-active creatures with exceptional low-light vision, thanks to a special reflective eye tissue called tapetum lucidum.

• Arboreal: They spend their lives in trees and rarely descend to the ground.

• Solitary & Stealthy: Timid and quiet, they lead solitary lives, only interacting during mating seasons.

• Very Slow Movers: Their movements are so slow and deliberate that they're often mistaken for being lethargic.

Is the Slow Loris Dangerous? Yes—And Here's Why

How Does Its Venom Work?

The slow loris has a unique venom delivery system among mammals:

• Venom Source: Not in their saliva—but in a gland on the inside of their elbows called the brachial gland.

• Activation: They lick this gland, mixing the secretion with their saliva to make it venomous before biting.

• Effects on Victims: The venom can be lethal to small animals and cause severe symptoms in humans.

Symptoms of a Slow Loris Bite

If bitten by a venomous slow loris, symptoms can include:

• Drop in blood pressure

• Burning sensation in the mouth and throat

• Involuntary muscle contractions

• Breathing difficulties

• Cardiac irregularities

• Loss of consciousness

• In rare cases, death from anaphylactic shock

Treatment: Seek immediate medical attention. Doctors typically administer tetanus shots, antibiotics, and monitor for allergic reactions.

Where Do Slow Lorises Live?

Slow lorises are native to Southeast Asia’s tropical rainforests, primarily found in:

• Vietnam

• Indonesia

• Malaysia

• The Philippines

• India

• Bangladesh

They are strictly arboreal and require dense jungle canopies to survive. Deforestation and habitat loss have severely impacted their population.

What Do Slow Lorises Eat?

Omnivorous Diet

Slow lorises eat both plant and animal matter:

• Fruits & Nectar

• Insects

• Bird eggs

• Small reptiles

• Snails and mollusks

Interestingly, they can consume some toxic plants that are harmful to humans.

Slow Metabolism

Despite their diverse and nutritious diet, slow lorises have an unusually slow metabolism, similar to sloths. Scientists believe this helps them digest complex food items, including those containing toxins.

Slow Loris Reproduction and Lifecycle

Mating Behavior

• Males compete for females and may use their venom in fights.

• Females signal readiness through vocalizations and urine marking.

• Internal fertilization occurs in the trees, and males may deposit a copulatory plug to prevent other males from mating with the same female.

Reproduction Cycle

• Polygamous: One female may mate with multiple males.

• Multiple heat cycles: Females go into estrus several times a year, each lasting about 30 days.

• Gestation period: Approximately 188 days.

• Litter size: Typically one baby, though twins are possible.

• Parental care: Females are highly protective and may use their venom defensively.

• Weaning: Offspring are weaned between 3–6 months.

• Sexual maturity: Reached at about 20 months.

Why You Shouldn’t Keep a Slow Loris as a Pet

Despite their cute appearance, slow lorises are wild animals and not suitable as pets. Here’s why:

• Illegal Wildlife Trade: Many are captured from the wild, and their venom glands are cruelly removed—often improperly.

• High Mortality: Captivity causes stress, reproductive issues, and early death.

• Ethical Concerns: Keeping wild animals as pets fuels extinction by reducing wild populations and encouraging poaching.

Note: The slow loris has been listed as an endangered species since 2012 and is protected under international law.

Final Thoughts: Protecting the World’s Only Venomous Primate

The slow loris is one of nature’s most fascinating yet vulnerable creatures. With their wide eyes, stealthy movements, and venomous bite, they remind us how diverse and complex the primate world can be.

If you care about wildlife, say no to exotic pet ownership and help raise awareness of conservation efforts. Let these animals live safely in their natural rainforest homes.

Bibliography

Dodd, T., Ankel-Simons, F., Berkowitz, B., et al. (2018) Nycticebus- an overview. Available at: https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/nycticebus

Peña, P. (2013) “Nycticebus coucang” Available at: https://animaldiversity.org/accounts/Nycticebus_coucang/

Beatty, R., Beer, A., & Deeming, C. (2010). The book of nature. Great Britain: Dorling Kindersley.

animal tags： slow loris