Euathlus truculentus blue
Chilean Blue Femur - complete care guide
Chilean Blue Femur
Temperature
20-24 °C
Target ambient range
Humidity
50-65 %
Substrate / enclosure RH
Adult DLS
8-10 cm
Average - varies per individual
Moult interval
Sling 4-9w - Juv 2.3-4mo
Adult 11-16mo
Adult cycle = mature females; males never moult again after maturity
About
The metallic blue-femur colour form of Euathlus truculentus - the type species of the genus, described by L. Koch in 1875 from central Chile and confirmed valid in the World Spider Catalog. A small, beautifully marked dwarf (8-10 cm) from Mediterranean scrubland around Coquimbo and Valparaíso: dark body, glowing blue-grey femora and famously placid "guinea pig" temper. One of the calmest tarantulas in the hobby - slow-moving, inquisitive, almost never defensive. Very slow-growing and cool-tolerant; captive-bred slings appear periodically in the UK at £50-65.
Husbandry cheat sheet
- Origin
- Chile (Coquimbo / Valparaíso regions)
- Habitat
- Mediterranean matorral scrubland
- Temperament
- Docile
- In your collection
- 0
Growth, lifespan & conservation
- Growth rate
- Slow
- Maturity
- ♀ 72mo ♂ 54mo
- Lifespan
- ♀ 20yr ♂ 5yr
- Continent
- South America
- UK availability
- Uncommon
Care Guide
Euathlus truculentus blue
Chilean Blue Femur - a complete husbandry sheet. Use as a starting point and adjust to your individual specimen.
What size enclosure does a Chilean Blue Femur Tarantula need?
Adults
20 × 20 cm (8 × 8 in) is plenty for a mature adult. Floor space matters more than height.
Slings & Juveniles
House spiderlings in small, appropriately sized deli cups or sling enclosures. They grow slowly - upgrades come every few moults.
To map exact floor space and substrate safety limits for your setup, use our free interactive tarantula enclosure planner.
What temperature and humidity does a Chilean Blue Femur Tarantula need?
Heating
The Chilean Blue Femurs is comfortable at 20-24 °C and tolerate cool UK room temperatures year-round without supplementary heat; only warm the room if it stays under 15 °C for long spells.
Humidity
50-65 %: dry-side husbandry - mostly dry substrate, full water dish, one corner overflowed occasionally. Mediterranean scrub species, not rainforest.
Ventilation
Cross-ventilation is essential - side-vented enclosures, never stagnant.
What substrate is best for a Chilean Blue Femur Tarantula?
Recommended Mixes
Depth
5-8 cm
Notes
Keep substrate dry to barely moist - never soaking. Pack it firm; 5-8 cm suits their shallow scrapes.
How do you set up a Chilean Blue Femur Tarantula enclosure?
Décor
The Hide
A low cork bark slab, half-log or resumed rock crests - they adopt scrapes under décor rather than deep burrows.
Water
Always provide a shallow fresh water dish. Keep it full and clean it regularly.
Lighting
No special lighting needed. Ambient room light is enough.
How often should you feed a Chilean Blue Femur Tarantula?
Good Feeders
Long refusal worrying you? Separate premoult fasting from genuine problems with our "Is my T okay?" checker.
Is my Chilean Blue Femur Tarantula dying or moulting?
Pre-moult signs to look for
Refusing food for weeks is normal before a moult - a healthy Chilean Blue Femur Tarantula fasting is almost never an emergency in itself. Watch for slowing down and spending more time in the hide, laying a thick moult mat of web on the floor. New World species like this one often show a bald spot on the abdomen that darkens to near-black as the new skin underneath readies - a darkening bald patch is a reliable countdown, not a disease.
On its back is MOULTING, not dying
A Chilean Blue Femur Tarantula lying upside down or on its side with legs curled inwards is almost certainly mid-moult. Do not touch it, do not right it, do not mist it - just remove any live prey (crickets can kill a defenceless moulter) and leave the room.
How long between moults?
For this species, expect a moult roughly every 30-60 days for spiderlings, every 70-120 days for juveniles, and every 150-240 days for sub-adults, with adult females moulting around every 11 months (up to 16 months at the extreme). Males never moult again after their ultimate (mature) moult.
After the moult: fang hardening time
The new exoskeleton stays soft, with fangs that cannot grip, for roughly 7 days in this species. Offer no food and no handling for about 7 days - feeding too early is how fresh moulters get injured. The shed exuvium is also the best sexing tool there is - see our tarantula sexing guide for what to look for.
Genuinely worried about behaviour that is not moulting? Our "Is my T okay?" triage tool walks the danger signs one by one.
What ongoing care does a Chilean Blue Femur Tarantula need?
🪞 Moulting
Signs: refuses food, abdomen darkens and goes glossy, becomes sluggish, often seals the hide entrance. During the moult: do not disturb, remove any live prey, keep water available. Wait until the fangs are black and hard (about a week for adults, 1-2 days for slings) before feeding again. Adult intervals apply to mature FEMALES - a mature male never moults again.
🧹 Cleaning
Daily: check the water dish. Weekly: remove uneaten prey boluses and spot-clean. Full deep clean only every few months.
✋ Handling
Among the most tolerant tarantulas in existence - the classic "beginner handling" species. Still handle rarely, at floor level, over a soft surface.
What are the most common mistakes when keeping Chilean Blue Femur Tarantulas?
✓ What They Love
- Fresh water dish at all times
- Cross-ventilation
- Cool, stable room temperature - no heat mat needed most of the year
- A low hide and substrate deep enough for shallow scrapes
- Patience - this is a very slow-growing species
✕ Common Mistakes
- Soaking-wet substrate
- Supplementary heat above ~27 °C - a cool-climate species
- Daily misting
- Large oversized enclosures - dwarf species hunt poorly in them
Keep exploring: related care guides
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