Javillo
Hura crepitans
Native Region
Tropical Americas
Max Height
30-60 meters
Family
Euphorbiaceae
Conservation
LC
Uses
Distribution in Costa Rica
Legend
Elevation
0-800m
Regions
- Limón
- Alajuela
- Heredia
- Puntarenas
- Guanacaste
Season
Flowering
Feb-Mar
Fruiting
Apr-Jun
Javillo (Sandbox Tree)
The Javillo (Hura crepitans), also known as the Sandbox Tree or Dynamite Tree, is one of the world's most dangerous trees—and one of the most fascinating. Its trunk is covered in sharp conical spines, it exudes caustic milky sap that causes severe burns and blindness, and its pumpkin-shaped seed pods explode with a loud bang, launching seeds at speeds up to 250 km/h over distances of 100 meters. Despite these defenses, it's a magnificent forest giant that plays important ecological roles.
Quick Reference
- Scientific Name
- Hura crepitans
- Family
- Euphorbiaceae (Spurge Family)
- Max Height
- 30-60 m
- Trunk Diameter
- Up to 3 m
- Conservation
- Least Concern
- Key Feature
- Spiny trunk, explosive pods
iNaturalist Observations
Community-powered species data
2500
Observations
186
Observers
📸 Photo Gallery
Photos sourced from iNaturalist's community science database. View all observations →↗
Taxonomy and Classification
- Hura: From an indigenous South American name - crepitans: Latin for "crackling" or "rattling"—referring to the explosive sound of the seed pods - Sandbox Tree: Colonial-era use—dried pods were filled with sand and used to blot wet ink - Dynamite Tree: Modern name for the explosive seed dispersal
Common Names
| Language/Region | Common Name(s) | Meaning |
|---|---|---|
| Spanish (Costa Rica) | Javillo, Jabillo | Indigenous name |
| Spanish (Caribbean) | Ceiba blanca, Salvadera | White ceiba / sandbox |
| English | Sandbox Tree, Dynamite Tree | Historical use / explosive pods |
| English (Caribbean) | Monkey No-Climb | Spines prevent climbing |
| Brazil | Assacu | Indigenous name |
Physical Description
General Form
The Javillo is an enormous deciduous tree, among the largest in Central American forests. The trunk is straight, massive, and covered with stout conical spines. The crown is broad and spreading, creating dense shade. Everything about this tree says "stay away"—and for good reason.
Defensive Arsenal
The Spiny Trunk
- Type: Stout, woody, conical spines
- Size: 1-5 cm long
- Coverage: Entire trunk and major branches
- Persistence: Present throughout tree's life
- Purpose: Defense against climbing animals
- Danger: Can cause serious puncture wounds
Toxic Sap
- Color: Milky white latex
- Toxicity: Extremely caustic
- Effects on Skin: Severe burns, blistering
- Effects on Eyes: Temporary or permanent blindness
- Ingestion: Violent vomiting, diarrhea, death possible
- Compounds: Hurin, creptin (toxic proteins)
Explosive Seed Pods
- Shape: Flattened pumpkin, segmented
- Size: 5-8 cm diameter
- Segments: 15-20 carpels
- Mechanism: Dries, tension builds, EXPLODES
- Sound: Loud bang (like gunshot)
- Seed Velocity: Up to 250 km/h (70 m/s)
- Dispersal Distance: Up to 100 meters
- Danger: Can injure people nearby
Leaves & Flowers
- Leaves: Heart-shaped, large (10-20 cm)
- Flowers: Male = red spikes; Female = inconspicuous
- Deciduous: Drops leaves in dry season
- New Leaves: Bronze-red, beautiful
The Javillo is genuinely dangerous: - NEVER touch the sap — causes severe chemical burns - NEVER get sap in eyes — can cause blindness - NEVER stand under tree with ripe pods — exploding pods can injure - NEVER eat any part — all parts are highly toxic - NEVER burn wood — smoke is irritating and toxic If exposed to sap, wash immediately with large amounts of water and seek medical attention. Woodworkers must use extreme caution.
Distribution and Habitat
Native Range
Geographic Distribution
Distribution in Costa Rica
Found throughout lowland wet and moist forests on both slopes:
| Province | Abundance | Notes |
|---|---|---|
| Limón | Common | Caribbean lowlands, wet forests |
| Puntarenas | Common | Pacific wet forests, Osa Peninsula |
| Alajuela | Occasional | Northern lowlands |
| Heredia | Occasional | Caribbean slope lowlands |
| Guanacaste | Rare | Only wettest areas |
Habitat Preferences
- Elevation: Sea level to 1,000 m
- Climate: Tropical wet to moist
- Rainfall: 2,000-5,000 mm/year
- Temperature: 24-32°C
- Soil: Rich, moist, well-drained
- Light: Full sun to partial shade when young
- Habitat: Primary and secondary forests, riverbanks
Ecological Importance
Despite the Danger...
Despite its fearsome defenses, the Javillo plays vital ecosystem roles: - Canopy Giant: Creates forest structure, microhabitats - Seed Dispersal Innovation: Explosive dispersal colonizes gaps - Food Source: Some animals tolerate toxins - Nesting Sites: Large branches, cavities - Shade Provider: Dense canopy in forest gaps - Carbon Storage: Massive biomass accumulation The tree's defenses evolved against now-extinct megafauna—it's over- defended for today's world but remains ecologically important.
Wildlife Interactions
Adapted Consumers
- Parrots: Some species eat seeds (process toxins)
- Iguanas: Consume leaves with apparent tolerance
- Monkeys: Occasional consumers (learned avoidance mostly)
- Fish: Seeds used as fish poison by indigenous people
Tree Associates
- Epiphytes: Grow on branches (avoiding spines)
- Birds: Nest in canopy
- Insects: Various specialists
- Bats: Use large spreading crown
Ethnobotanical Uses
Traditional Uses
Indigenous Knowledge
Despite its toxicity, indigenous peoples developed uses for Javillo: - Fish Poison: Sap and seeds stupefied fish for easy catching - Arrow Poison: Toxic latex on hunting arrows - Medicine: Carefully prepared for specific ailments - Purgative: Controlled doses as powerful laxative - Ritual: Seeds used in ceremonies (careful handling) These uses required extensive traditional knowledge—DO NOT attempt!
Colonial "Sandbox" Use
In colonial times, before blotting paper was common, the dried seed pods were used as desk accessories: 1. Pods were collected after explosion (or carefully dried to prevent it) 2. Hollow segments were filled with fine sand 3. Placed on desks as inkwells or sand shakers 4. Sand was sprinkled on wet ink to dry it quickly This is how the tree got its English name "Sandbox Tree"—a curious bit of colonial-era office supply history!
Modern Considerations
| Use Category | Status | Notes |
|---|---|---|
| Timber | Limited | Difficult to work safely, irritating |
| Ornamental | Rare | Too dangerous for most settings |
| Fish Poison | Traditional only | Illegal in most jurisdictions |
| Medicine | Research interest | Compounds being studied |
| Novelty | Collectors | Seed pods as curiosities |
The Explosive Mechanism
How the Pods Explode
Nature's Ballistic Seed Launcher
The Javillo's seed dispersal is a marvel of botanical engineering: 1. Pod Development: Fruit grows as segmented capsule 2. Drying Phase: As pod dries, tissues contract unevenly 3. Tension Builds: Outer layers shrink faster than inner 4. Critical Point: Tension exceeds structural strength 5. EXPLOSION: Pod shatters along segment lines 6. Seed Launch: Seeds ejected at ~70 m/s (250 km/h!) 7. Distance: Seeds travel up to 100 m from parent tree The explosion sounds like a gunshot and can be heard from far away. It's one of the most dramatic seed dispersal mechanisms in nature.
To safely observe (from a distance!): - Timing: Dry season, when pods are mature - Conditions: Hot, dry days trigger more explosions - Distance: Stay at least 50 meters from trees with ripe pods - Sound: Listen for gunshot-like bangs - Aftermath: Look for pod fragments and scattered seeds Never collect ripe pods—they can explode in your hands or car!
Identification Guide
How to Identify Javillo
Definitive Features:
- Trunk covered in conical woody spines (unmistakable!)
- Large heart-shaped leaves
- Milky white sap (DON'T test this!)
- Pumpkin-shaped segmented seed pods
- Massive size (one of largest trees)
- Red male flower spikes when flowering
Where to See Javillo in Costa Rica
| Location | Access | Notes |
|---|---|---|
| Corcovado National Park | Trails | Large specimens in primary forest |
| Tortuguero National Park | Boat/trails | Caribbean lowland forests |
| La Selva Biological Station | Research station | Well-documented trees |
| Carara National Park | Trails | Transitional forest |
| Caribbean lowland roads | Roadsides | Occasional large trees |
| Osa Peninsula | Various trails | Old-growth specimens |
When observing Javillo: - Keep distance from the trunk (spines and sap) - Don't stand under trees with ripe pods (dry season!) - Don't touch fallen sap or pod fragments - Photograph from safe distance with zoom lens
- Warn others about the tree's dangers
External Resources
Community observations and photos
Tropical forest research
Detailed species information
References
📚 Scientific References & Further Reading
Janzen, D.H. (1983). Costa Rican Natural History. University of Chicago Press
Swaine, M.D. & Beer, T. (1977). Explosive Seed Dispersal in Hura crepitans. New Phytologist 78: 695-708
Sakai, S. (2001). Thrips pollination of androdioecious trees, Castilla elastica and Antiaris toxicaria. American Journal of Botany 88: 1004-1010
The Javillo is a tree that commands respect. Its arsenal of spines, toxic sap, and explosive pods represent millions of years of evolution against herbivores and seed predators. In an age when most dangerous megafauna are gone, the Javillo remains ready for battles that rarely come. Standing before one of these magnificent giants, covered in their armor of spines and reaching toward the canopy, you witness a living fortress—beautiful, terrifying, and utterly unforgettable. Just remember to appreciate it from a safe distance!
