The chaco golden knee is the tarantula most experienced keepers recommend when someone asks for a first spider, and the reason is temperament rather than looks. Grammostola pulchripes is a large, slow, unusually tolerant terrestrial from Paraguay and Argentina, reaching 7 to 8 inches with gold banding on dark legs. Females live 20 to 25 years. It is a forgiving animal that gives plenty of warning, eats reliably, and does not vanish into a burrow for months at a time like some beginner species do.
Species Overview
Chacos come from the Gran Chaco, a hot semi-arid lowland spanning Paraguay, northern Argentina, and parts of Bolivia. That habitat explains the care: warm, dry to moderately humid, with a scrape or burrow for shelter rather than deep permanent tunnels.
Adults are large, with a leg span of 7 to 8 inches and a heavy build. The body is dark brown to black with dense pale setae, and the joints on each leg carry the gold or yellow banding that gives the common name. Freshly molted animals look considerably brighter than ones due for a shed.
As a New World species, chacos have urticating setae, the barbed abdominal hairs kicked as a first defence. They are notably reluctant to use them compared to other New World genera, and many keepers report never seeing a chaco kick at all. The full picture of what that split means is in our comparison of tarantulas by hemisphere.
| Attribute | Details |
|---|---|
| Scientific name | Grammostola pulchripes |
| Adult size | 7 to 8 inches |
| Lifespan | 20 to 25 years female, 5 to 8 male |
| Difficulty | Beginner |
| Temperature | 72 to 82F (22 to 28C) |
| Humidity | 60 to 70% |
| Type | Terrestrial, opportunistic burrower |
| Growth rate | Slow to moderate |
Enclosure Setup
Adult enclosure: a 10 gallon tank or a similar footprint acrylic, around 12 by 12 inches minimum for a full-grown female. Floor space matters, height does not.
Substrate: 4 to 5 inches, packed firmly. A chaco is heavy enough that a fall can rupture the abdomen, so the air gap above the substrate should be no more than about 1.5 times the leg span. That is the governing rule for any ground dweller, and the full sizing logic is in our terrestrial tarantula enclosure guide.
Substrate mix: three parts coconut fibre, two parts topsoil with no additives, one part play sand. Add it slightly damp and press it down in layers so it holds a thumbprint. Chacos will excavate a scrape under their hide even though they are not committed burrowers.
Hide: a piece of cork bark laid on its side with one edge bedded in, and a small divot started underneath. Most chacos accept and extend it.
Water dish: shallow, always filled, and refilled rather than topped up.
Decor: a little dry leaf litter for web anchoring. Nothing tall, nothing hard, no stacked rocks.
Temperature and Humidity
Room temperature suits them across a wide band, 72 to 82F, and no supplemental heat is needed in most homes. If your room drops into the low 60s for extended periods, use a low wattage mat on a side wall with a thermostat, never underneath the enclosure.
Humidity sits comfortably at 60 to 70%, which most homes achieve without intervention. Chacos are more forgiving on this than tropical species and tolerate drier conditions well.
How to add moisture: pour water down one corner of the substrate every couple of weeks, or simply keep the water dish full and let evaporation handle it. Do not mist. Misting achieves little for the substrate and stresses the animal.
The one thing that actually kills them is a dried-out enclosure with an empty water dish. Dehydration presents as the legs folding beneath the body, which is the death curl, and it is usually reversible if caught early.
Diet and Feeding
Chacos are reliable feeders, which is part of what makes them a good first tarantula. A spider that eats when offered is a spider whose condition you can read.
What to offer: crickets, dubia roaches, red runners, and locusts. Prey should be no larger than the tarantula’s body length, and smaller is fine.
How often: adults every 7 to 14 days, juveniles every 5 to 7, slings every 3 to 5. Judge by abdomen size rather than by schedule. A plump abdomen means you can wait.
Remove uneaten prey within 24 hours. A cricket left in with a molting tarantula will chew on it, and that is a preventable death.
Fasting is normal. A chaco may refuse food for weeks or months, particularly before a molt or over winter. Provided the abdomen is not shrinking and water is available, this is not a problem. Adult females can fast for remarkably long stretches.
Because the intervals here are long and the signals are subtle, the dates matter more than the impressions. Recording feeds, refusals, and molts in our free invertebrate care app turns two decades of husbandry into a record you can actually consult.
Temperament and Handling
This is why the species is recommended. Chacos are slow, calm, and reluctant to react. A disturbed chaco typically walks away, and even when pressed it is far more likely to move off than to kick hairs or adopt a threat posture.
That said, the standard advice applies. Handling offers nothing to the spider and carries a real risk: a 7 inch tarantula dropped from waist height onto a hard floor can rupture its abdomen and die. If you handle at all, sit on the floor over carpet.
Normal behaviour is a spider that sits in the open or under its hide, moves slowly, webs lightly around the burrow entrance, and is visible far more often than a fossorial species.
A threat posture, meaning raised front legs and a reared body, is uncommon in this species and means back off. It is a warning, not a bluff to test.
Molting and Growth
Growth is slow to moderate, faster than a Chilean rose but nothing like an Old World species. Expect several years from sling to adult, with molt intervals stretching from every few weeks in early instars to once a year or less in a mature female.
Pre-molt signs: refusing food, a dark taut abdomen, a bald patch that darkens, reduced activity, and heavier webbing.
During a molt the tarantula flips onto its back, legs upward, and stays motionless for hours. This looks alarming and is entirely normal. Do not touch, mist, or move the enclosure. The full process is covered in our guide to tarantula molting.
After a molt, wait a week or two before feeding, since the fangs need to harden. Colours are at their brightest at this point.
Sexing becomes reliable from the shed exoskeleton once the spider is a few inches, and a mature male develops tibial hooks and swollen pedipalps at his ultimate molt. That distinction matters enormously here, since females live 20 to 25 years and males typically manage 5 to 8 in total, living only months after maturing.
Breeding
Worth understanding even if you never attempt it, since it explains why males are cheap and females are not.
A male reaches his ultimate molt and develops tibial hooks on his front legs, used to hold the female’s fangs clear during mating. From that point he has months rather than years, and he stops molting entirely.
Pairing involves introducing a mature male into the female’s enclosure and watching closely. He drums on the substrate to announce himself, and if receptive she responds. Cannibalism is a real risk, less routine than folklore suggests but common enough that breeders keep a catch cup ready and remove the male immediately afterward.
The egg sac follows weeks to months later and may contain several hundred eggs. Females are protective and will move and turn the sac. Breeders typically pull it after around four weeks and incubate it artificially, which is fiddly and easy to get wrong.
Realistically, this is not a beginner project. Slings are cheap and widely available precisely because experienced breeders produce them in volume, and there is no economic reason to attempt it with a first tarantula. It is worth knowing about mainly so you understand what a mature male means if you end up with one.
Buying a Chaco
Sling or adult is the main decision. Slings are inexpensive and you learn the animal as it grows, though a chaco sling means several years before it is impressive. Care at that stage differs enough to warrant its own approach, covered in our spiderling housing and feeding guide.
Juveniles at 2 to 3 inches are the practical compromise: hardier than slings, cheaper than adults, and already showing the species’ temperament.
Sexed females cost considerably more and are worth it if a 25 year animal is what you want. An unsexed juvenile is a coin flip between two decades and five years.
Captive bred is standard for this species, so there is no reason to buy wild caught.
Common Health Issues
Dehydration. Empty water dish, dried substrate. The leading preventable cause of death.
Fall injury. Excess height above the substrate, or a handling accident. Abdominal rupture is usually fatal.
Failed molt. Rare in this species, usually following a dried-out enclosure.
Mites. Uncommon in captive bred stock kept clean. Remove uneaten prey and boluses promptly.
Prey injury during a molt. Entirely preventable by removing crickets within 24 hours.
Nothing that needs a vet. Tarantula medicine barely exists. Prevention through husbandry is the whole toolkit.
FAQ
Are chaco golden knees good for beginners?
Yes, and they are among the most recommended first tarantulas. They are slow, calm, reluctant to kick hairs, reliable feeders, and visible rather than permanently burrowed. The only strict requirements are a filled water dish and limited height above the substrate.
How big do chaco golden knee tarantulas get?
Seven to eight inches in leg span as adults, with a heavy build, making them one of the larger commonly kept New World species. They reach that size gradually over several years rather than growing quickly.
How long do chaco golden knees live?
Females commonly reach 20 to 25 years. Males live 5 to 8 years in total and only months after their final molt. An unsexed juvenile is therefore a significant gamble on how long you will have the animal.
Do chaco golden knees bite?
Rarely. They are among the most reluctant tarantulas to bite and typically walk away rather than defend. As a New World species the venom is mild, comparable to a wasp sting, though the fangs on a 7 inch spider are substantial regardless.
How often should I feed a chaco golden knee?
Adults every 7 to 14 days, juveniles every 5 to 7, slings every 3 to 5. Judge by abdomen size rather than by the calendar, and expect long voluntary fasts before molts, which are normal and not a cause for concern.
Do chaco golden knees burrow?
They dig a scrape under their hide rather than building permanent tunnels, so they stay visible far more than fossorial species. Provide 4 to 5 inches of firmly packed substrate and a cork bark hide with a divot started underneath.
Track Your Tarantula with InvertMate
A female chaco can outlive several phones, and the molt and feeding history that tells you whether she is thriving only exists if you recorded it. InvertMate lets you log every molt with dates and photos, record feeding refusals across long fasts, and monitor enclosure temperature and humidity. Free on the App Store & Play Store.