Pterinochilus sp. “Arusha”

Pterinochilus sp. “Arusha” hails from the Arusha region of northern Tanzania, East Africa, in the shadows of Mount Meru and near the Serengeti’s edge. There, the climate is warm and variable, with pronounced wet and dry seasons. These tarantulas inhabit savannahs, grasslands and woodland edges, where the substrate allows for burrowing and there’s plenty of leaf litter for hiding. Rainfall can be heavy but brief, with humidity spiking during the wet season and falling quite low at other times. In their native range, day and night temperatures can fluctuate, so our captive care should aim to mimic that mix of warmth and ventilation.

As adults, Pterinochilus sp. “Arusha” typically reach 11–13 cm diagonal leg span, with the gents running a tad smaller and less bulky than the ladies. Males are leggier and svelter, while females bulk out both in body and leg thickness. Growth rates mean these aren’t the giants of the hobby, but their long, spindly legs and striking patterns give them heaps of presence. Expect your adult to need a roomy enclosure that allows both horizontal and vertical webbing—their real estate demands aren’t modest!

In captivity, Pterinochilus sp. “Arusha” straddles that quirky border between fossorial and semi-arboreal. Youngsters dig extensive burrows, while older spiders may venture up their web tunnels or decorate higher parts of their enclosure. Expect energetic excavating, a flair for vertical web curtains, and a fondness for irregular tunnel systems. They’ll make good use of hides, web up entire corners, and seldom turn down a chance to rearrange the décor. You may not see much of yours by day, but evidence of their adventures will be everywhere—if you like your spiders with a dash of DIY spirit, this is the species for you.

Females of this species can be surprisingly long-lived, often reaching 10–14 years with good care. Males, the unlucky chaps, mature faster but only live for 2–4 years—once they reach adulthood, it’s a short dash to the finish line. This means investing in a female means years of companionship (well, as companionable as a speedy Old World can be). With appropriate housing, temperature, and feeding, you can expect good longevity—just don’t expect them to knit you a jumper in your golden years together.

Pterinochilus sp. “Arusha” boasts a medium-to-fast growth rate compared to other tarantulas, especially for an Old World. Slings can zip from tiny to leggy within 2–3 years if well fed and kept warm. Growth may stall in cooler months, and fasting or pre-moult periods will delay it, but generally, you won’t be waiting half your lifetime for that first adult moult. Provide steady food, hydration and gentle warmth, and watch those legs get longer by the month!

This is not your nan’s gentle Brachypelma! Pterinochilus sp. “Arusha” is brisk, bold and rather opinionated. Known for their lightning-fast sprints, threat poses, and a willingness to stand their ground, they aren’t shy and never dull. That said, many keepers observe a “see you, I’m gone” attitude rather than outright aggression—expect teleporting retreats rather than fanged confrontations. Handling is a no-no, so enjoy from behind the glass, with tongs and a poker-face. Seasoned keepers love them for their antics.

Aim for an enclosure temperature of 22–26°C, mimicking their warm East African home. They can tolerate short dips to 20°C (British winter, anyone?) and brief peaks to 28°C, but keep extremes to a minimum. Day-night temperature gradients are fine—this species is no stranger to a chilly night. Heat mats are usually unnecessary unless your house is colder than a fridge; if you must use supplemental heat, ensure it’s applied to the side and monitored to avoid drying out the enclosure. A digital thermometer and common sense go a long way!

Aim for 50–65% relative humidity—enough to stop the spider crisping up, but not so much you’re hosting a mushroom farm. Let the top half of the substrate dry between light mistings, but ensure the lower layers are always very slightly moist, especially for slings. Good cross-ventilation is vital: this species dislikes stuffy air, and stagnant conditions invite mould. Always provide a sturdy water dish, even if the spider uses it as a swimming pool for its locusts.

They’re not quite the hobby’s invisible ninjas, but you won’t always see your “Arusha” out and about. Juveniles and adults alike spend ample time hidden in silk-lined burrows or behind elaborate curtains of web, emerging mostly at twilight or after lights-out for a mooch. However, if you keep the enclosure interesting, you’ll often spot them rearranging web, sitting at a burrow entrance, or launching a surprise attack on unsuspecting prey. A true treat for patient observers and lovers of web art!

If you like your spiders industrious, you’re in for a treat. Pterinochilus sp. “Arusha” are master web architects, spinning dense silk tunnels, ramps, and curtains throughout their enclosure. They use webbing to line burrows, form trapdoors, and create alarm systems (so they always know when you’re poking about). New web engineering appears with every moult, and the whole setup can shift overnight. Keepers adore their creativity—just don’t expect them to tidy up afterwards.

These spiders are ferocious eaters, especially as juveniles. Suitable prey includes crickets, locusts, dubia roaches, and for smaller slings, micro crickets or worm pieces. Feed slings twice per week, juveniles every 5–7 days, and adults every 10–14 days. “Arusha” will usually snatch prey right at the burrow entrance or from the safety of their web. Be wary not to overfeed—plump abdomens and fasting before moult are normal, so don't panic if they turn down a meal. Always remove uneaten prey after 24 hours, and never feed right after a moult. Strong feeding responses make them exciting dinner guests, but do mind those ultra-fast strikes!

Go for a secure, escape-proof enclosure with good ventilation—think glass or acrylic, with clips or a latch. Provide 10–15 cm of loose, diggable substrate (coco fibre with topsoil is a winner) for burrowing. Add a starter hide (cork bark, half flowerpot) and anchor points for webbing (sticks, rocks, fake plants). Adults need room for both vertical and horizontal webbing, with more floor space than height, but don’t skimp on width. Include a shallow, sturdy water dish. Regular maintenance is key, as they do like to obscure every surface with a new silk masterpiece. Cleaning around these hyper spiders is a challenge, but that’s half the fun.

Best suited to intermediate or advanced hobbyists who know the ropes of Old World husbandry. Their speed, defensive nature, and propensity to bolt during enclosure maintenance make them less forgiving for beginners. However, for keepers familiar with tongs, trapdoors and a quick hand, “Arusha” offers rewarding behaviour and a bit of a challenge. If you cut your teeth on calmer New Worlds and fancy an Old World adventure, this species ticks all the boxes!

Pterinochilus sp. “Arusha” offers hobbyists a heady mix of beauty, energy and behavioural intrigue. They’re not for the faint-hearted or slow-handed, but their stunning gold and ochre patterns, creative webbing, and fascinating burrowing make them a showpiece species. Ideal for keepers who want more than a motionless pet rock—but with fewer bitey dramas than the infamous OBT. Bring your best enclosure game, a respectful distance, and a sense of humour, and you’ll be rewarded by one of the most dynamic Old Worlds out there. Just don’t expect a lap spider!