Omothymus sp. Magnus
Magnus Earth Tiger - complete care guide
Magnus Earth Tiger
Temperature
24-28 °C
Target ambient range
Humidity
75-85 %
Substrate / enclosure RH
Adult DLS
18-22 cm
Average - varies per individual
Moult interval
Sling 3-6w - Juv 1.7-2.8mo
Adult 9-13mo
Adult cycle = mature females; males never moult again after maturity
About
The Magnus Earth Tiger - a huge slate-and-cream Sumatran form that hit the UK trade in 2025 and may be (or be close to) Omothymus rafni. Conflicting hobby reports about whether it is more arboreal or fossorial - the safe answer is both: give height AND deep substrate and let the spider choose. Either way you get one of the largest Old World forms in the hobby (up to 22 cm), a monstrous feeding response, defensive speed and no urticating hairs. Rare, expensive (£75+ slings) and firmly for experienced Old World keepers.
Husbandry cheat sheet
- Origin
- Sumatra (trade)
- Habitat
- Tropical rainforest - burrows and tree root tangles
- Temperament
- Defensive
- In your collection
- 0
Growth, lifespan & conservation
- Growth rate
- Fast
- Maturity
- ♀ 36mo ♂ 24mo
- Lifespan
- ♀ 15yr ♂ 4yr
- Continent
- Asia
- UK availability
- Rare in the hobby
Care Guide
Omothymus sp. Magnus
Magnus Earth Tiger - a complete husbandry sheet. Use as a starting point and adjust to your individual specimen.
What size enclosure does a Magnus Earth Tiger Tarantula need?
Adults
40 × 30 × 30 cm with 12+ cm of substrate plus vertical cork - cover both lifestyles.
Slings & Juveniles
Tall-ish tubs with 8 cm of substrate and a cork tube - juveniles explore both lifestyles.
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 Magnus Earth Tiger Tarantula need?
Heating
The Magnus Earth Tigers is comfortable at 24-28 °C. UK homes need supplementary warmth for much of the year; warm the room, never the tank floor.
Humidity
75-85 %: keep the lower substrate damp (never sodden) with strong airflow.
Ventilation
Strong cross-ventilation with high humidity - the classic Old World balance.
What substrate is best for a Magnus Earth Tiger Tarantula?
Recommended Mixes
Depth
12-15 cm
Notes
Deep (12 cm+) and packed - for the burrowers; the aerial builders will web above it regardless.
How do you set up a Magnus Earth Tiger Tarantula enclosure?
Décor
The Hide
Cork tubes and deep substrate both offered - some build aerial web funnels, others burrow; adult choices are individual.
Water
Large shallow dish - a 20 cm spider drinks properly. Keep full and clean.
Lighting
Ambient room light only. Avoid bright spots.
How often should you feed a Magnus Earth Tiger Tarantula?
Good Feeders
Long refusal worrying you? Separate premoult fasting from genuine problems with our "Is my T okay?" checker.
Is my Magnus Earth Tiger Tarantula dying or moulting?
Pre-moult signs to look for
Refusing food for weeks is normal before a moult - a healthy Magnus Earth Tiger 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. Old World species do not flick urticating hairs, so there is no bald patch to watch - rely on fasting, lethargy and hide time instead.
On its back is MOULTING, not dying
A Magnus Earth Tiger 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 20-40 days for spiderlings, every 50-85 days for juveniles, and every 120-190 days for sub-adults, with adult females moulting around every 8.7 months (up to 12.7 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 Magnus Earth Tiger Tarantula need?
🪞 Moulting
Moults in the burrow or web funnel depending on lifestyle. Do not disturb; keep prey out and humidity steady; wait until the fangs are black and hard before feeding. Adult intervals apply to mature FEMALES - a mature male never moults again.
🧹 Cleaning
Spot clean with long tongs; refresh the water dish weekly. Full cleans need a full rehouse plan.
✋ Handling
Never - large, fast, defensive Old World. Catch cup and lid discipline at all times.
What are the most common mistakes when keeping Magnus Earth Tiger Tarantulas?
✓ What They Love
- Height AND deep substrate - let it choose its lifestyle
- Warm, humid, strong cross-flow
- Long tongs and lid discipline
- Anchor points for heavy webbing
- Respect: fast, defensive, potent venom
✕ Common Mistakes
- Free handling or open-lid maintenance
- Dry conditions
- Small enclosure - a 20 cm Old World needs room
- Trusting the "arboreal" OR "fossorial" label alone
Keep exploring: related care guides
More ground-dwelling species and close relatives from our full library:
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