Heterometrus silenus
Heterometrus silenus is an Asian forest scorpion native to Vietnam and widely distributed across Southeast Asia, including Thailand, Malaysia, and neighboring regions. It is among the most common Heterometrus species in the hobby. Previously often confused with H. petersii, its taxonomy and Indochinese range have been clarified through recent revisions.

HABITAT
🌍 Geographic Range:
Heterometrus silenus is native to parts of Southeast Asia, primarily within the Indochinese region. It has been documented in Vietnam and adjacent areas of Cambodia, with records also extending into eastern Thailand.
Recent taxonomic revisions clarified its range in Indochina, distinguishing it from related species that inhabit Malaysia or India. A former subspecies reported from Mindanao in the Philippines (Heterometrus petersii) was synonymized with H. silenus, suggesting the species’ distribution may include the southern Philippines as well.
Overall, H. silenus appears to be widespread in tropical forests of Vietnam and neighboring countries in mainland Southeast Asia.
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🏡 Microhabitat Preferences:
Heterometrus silenus typically inhabits humid tropical and subtropical forests. It lives in vegetated, densely canopied areas where it can find shelter under leaf litter, fallen logs, or rocks. By day it remains hidden in burrows or natural crevices, emerging at night to hunt on the forest floor.
The species favors warm, moist microhabitats, for example, the damp undergrowth of rainforests or plantations which provide both high humidity and ample cover.
Though largely terrestrial, H. silenus is adept at digging and will construct or adopt burrows for refuge.
Physical Description
📏Size:
Heterometrus silenus is a large scorpion species, with adults typically reaching lengths of 12 to 15 cm (5 to 6 inches).
Pincers :
The pincers are large, and robust, with a smooth texture.
Tail
Carapace:
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🎨Coloration:
This species has a glossy dark brown to black exoskeleton, which can appear slightly reddish under certain lighting conditions.
Heterometrus silenus, has a dark brown/blacktelson, it tends to rely on its pincers rather than its sting due to it's lack of venom potency.
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🔎Detail:
The carapace is smooth and shiny, with a pair of medium-sized central eyes and several smaller lateral eyes.
Captive Care
📏Enclosure Size:
Minimum: 10 litres is plenty for one adult.
Glass enclosures 30x30x20(WxDxH).
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🌡️Temperature:
24–28 °C
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💧Humidity:
80%.
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🌱Substrate:
Water-retentive soil
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⏰Feeding schedule:
Once every week
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🥣Water Source:
Very important, Hetermetrus species drink a lot of water, water dish must always have water. Overflow water dish to soak the soil around the scorpion, this provides more humidity and allows the scorpion to more easily find the water source.
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🍃Ventilation
In order to acquire and maintain optimum humidity, you must decrease the ventilation. Too much ventilation such as reptile-like enclosures let out humidity too quickly and allow the substrate to dry out very quickly.
VENOM
💉Heterometrus silenus is not considered a dangerous scorpion to humans. Its venom potency is relatively low. No human fatalities have been attributed to Heterometrus stings, and envenomations generally produce only mild localized symptoms. A sting from H. silenus can cause pain, swelling, redness, and temporary numbness at the bite site, effects often likened to a wasp or bee sting in severity.
For a healthy adult, the discomfort typically subsides within a few hours to a couple of days and is rarely life-threatening or systemic. As is common among large scorpions with robust pincers, H. silenus relies more on strength than venom to subdue prey, and consequently its venom is relatively mild, not medically significant unless the victim has an allergy.
Molecular Profile of H. silenus Venom
Despite its low toxicity to humans, the venom of H. silenus is biochemically complex. Proteomic and transcriptomic analyses of related Heterometrus species’ venom reveal a diverse cocktail of peptides and proteins. These include multiple families of ion-channel neurotoxins (e.g., peptides targeting potassium and calcium channels), several families of antimicrobial and cytolytic peptides, phospholipase enzymes, serine proteases, and other bioactive components. Such venom composition suggests that Heterometrus venom serves to immobilize a variety of prey (from insects to small vertebrates) and also contains compounds with potential antibacterial or therapeutic properties.
Researchers have found peptides in Heterometrus venom with antimicrobial effects (e.g., scorpine, pandinin) and others being investigated for medicinal use. The presence of these molecules has drawn scientific interest, for example, exploring Heterometrus venom for drug discovery or as bioinsecticides.
In summary, while H. silenus’ venom poses little danger to people, it is a rich source of biochemical compounds that underpin its predatory ecology and hold value for biomedical research.
STATS
LATIN NAME:
• Heterometrus silenus
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COMMON NAME:
• Vietnamese Forest Scorpion
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TEMPERATURE
• 24°- 28°
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TEMPERAMENT:
• Tempremental
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HUMIDITY:
• 80%
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COMMUNAL:
• 4/5
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SIZE:
• Up to 14cm
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ECOLOGY:
• Terrestrial/Fossorial
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SUBSTRATE:
• Water-retentive soil
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ORIGIN:
• Vietnam, Southeast Asia
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FACTS
Conservation Status
Currently, Heterometrus silenus has not been formally evaluated by the IUCN Red List, meaning it does not have an official global conservation status. In its native range, the species is not known to be under acute threat and is considered relatively common in appropriate habitats.
Field surveys and hobbyist reports indicate H. silenus is locally abundant in some Vietnamese and Cambodian forest areas, and it remains one of the more frequently encountered large scorpions in Southeast Asia.
Like many forest-dependent species, H. silenus could be impacted by ongoing habitat loss. The deforestation and conversion of Southeast Asian rainforests for agriculture or development may reduce the available habitat for these scorpions over time. At present, H. silenus has a broad distribution and there is no evidence of rapid population declines, so it would likely qualify as Least Concern if assessed, but this assumes that sufficient habitat remains intact.
Another consideration is the collection pressure on wild scorpions. H. silenus is often collected for trade in the hobby and occasionally for use as food or in traditional medicine. In certain regions (e.g., parts of Thailand and Vietnam), there have been reports of local people harvesting large scorpions to sell in markets. Unregulated over-collection could pose a localized threat, especially if it targets breeding females or depletes populations faster than they can reproduce. However, at the scale of its entire range, there is no current indication that H. silenus is endangered. Conservationists have noted the importance of preserving forest habitats and monitoring trade, to ensure this species remains common.
In summary, H. silenus is not protected by specific laws and is not listed as threatened, but maintaining its habitat and preventing unsustainable harvesting will be key to its long-term conservation.
Human Interactions
Pet Trade:
Heterometrus silenus is a popular scorpion in the exotic pet trade due to its impressive size and generally mild temperament. Enthusiasts value this species as a “beginner-friendly” scorpion. In captivity, H. silenus adapts well to terrarium life, and it has become one of the most common Heterometrus species bred or sold internationally. The confusion in earlier years between H. silenus and similar species (like H. laoticus or H. spinifer) led to many specimens in the pet trade being mislabeled, but recent taxonomic and hobbyist data helps breeders accurately identify this species.
Its availability in the pet market suggests that a significant number are collected from the wild (particularly from Vietnam or Thailand) or are being captive-bred to meet demand. Responsiblescorpion enthusiasts are advised to obtain captive-bred individuals when possible, to reduce pressure on wild populations.
Stings:
Encounters between H. silenus and humans in its native area occur when the scorpions wander into rural homes or when people venture into the scorpion’s habitat (for farming, logging, etc.). H. silenus is defensive and will sting if provoked or accidentally stepped on, but fortunately its sting is not dangerous. Typical symptoms include sharp pain, swelling, and localized inflammation that subsides within hours or a day. Traditional knowledge in regions like Thailand has led to herbal remedies for scorpion stings – for instance, certain plant extracts are used in Thai folk medicine as an antidote or soothing balm for Heterometrus stings, helping to reduce pain and inflammation. In clinical practice, treatment for a H. silenus sting usually involves cleaning the wound, cold compress to manage swelling, and oral analgesics or antihistamines if needed. There are no specific antivenoms produced for Heterometrus species (unlike some deadly scorpions), primarily because their venom is not life-threatening. Public education in endemic areas often emphasizes that these large scorpions, while intimidating in appearance, are considerably less dangerous than smaller, more venomous scorpion species.
Use in Food and Medicine:
In some parts of Southeast Asia, H. silenus and other large forest scorpions are used by humans as novelty food or in traditional medicinal preparations. Tourists and locals in night markets of Thailand or Vietnam may encounter “scorpion on a stick,” where large black scorpions (often Heterometrus species) are skewered and fried as an exotic snack. Reports specifically note that scorpions identified as H. silenus (or its close relatives) are harvested in Thailand to be sold as fried snacks in markets. Additionally, these scorpions are sometimes infused in rice wine or spirits – a practice in parts of Vietnam and China where scorpion-infused alcohol is believed to have tonic or medicinal properties (such as pain relief or increased vitality). While such uses are relatively small-scale and cultural, they do mean H. silenus has economic value to local collectors. Over-collection for culinary or medicinal use does not appear to be severe at this time, but any sustained commercial demand could affect local populations if not monitored.
Cultural Importance:
The name silenus refers to Silenus, a woodland deity from Greek mythology associated with forests and wildlife, reflecting the scorpion’s forest-dwelling nature. In local folklore of its range, scorpions often feature as symbols of potency or are used in traditional rituals. In Cambodia and Vietnam, villagers sometimes refer to large black scorpions as “forest spirits” or attribute protective qualities to them. Farmers often view them as beneficial predators that help control insect and rodent populations, though their formidable appearance also makes them a source of fear and fascination.