Cobalt Blue Tarantula (Cyriopagopus lividus)
A burrowing tarantula from the monsoon forests of Myanmar and Thailand whose legs flash an electric, metallic blue in the right light. It is also one of the most defensive tarantulas in the family: fast, reluctant to be seen, and equipped with an Old World bite that hurts far more than the mild venom of its New World relatives.
By Dr. James WatuwaPublished February 15, 2019Updated September 13, 2026✓ Reviewed by Dr Richard J. Pearce (PhD)
In this guide
- Physical description and identification
- Where the cobalt blue tarantula lives
- Are cobalt blue tarantulas venomous?
- Can cobalt blue tarantulas bite?
- Ecological importance and behaviour of the cobalt blue tarantula
- Similar tarantulas and how to tell them apart
- Quick facts
- Did you know?
- Frequently asked questions
Physical description and identification
The cobalt blue is a medium-sized, powerfully built burrowing tarantula. Its striking feature is the colour of the legs, which shift from near-black to a vivid metallic blue as the light catches them. The body itself is far plainer than photographs suggest: a grey to tan carapace and abdomen, usually with a darker chevron or herringbone marking down the top of the abdomen.
Adults
- Size: a leg span of about 11–13 cm (4.5–5 in) is normal for an adult, with a body length near 5 cm. Females are stockier; males are lighter and proportionally longer in the leg.
- Colour: the blue is structural, generated by nanostructures inside the hairs rather than by any pigment, so it disappears completely in flat or indirect light and a resting spider can look plain charcoal. Adult females carry the strongest blue. After his final moult a male usually loses most of it and turns brownish-bronze with paler leg segments.
- Eyes: eight small eyes grouped on a raised tubercle. Sight is almost irrelevant to a spider that lives underground; vibration through the silk does the work.
- Distinctive features: the front legs and palps are heavy and spade-like for digging. As an Old World tarantula it has no urticating hairs — the abdomen never develops the bald patch you see on a New World species. Mature males have tibial hooks and swollen pedipalps.
Eggs and egg sac
The female seals herself into her burrow to breed and produces a white sac that she cradles and turns, bringing it to the warmer upper part of the tunnel during the day. Clutches are large by tarantula standards — typically on the order of a hundred eggs, sometimes several hundred — and she does not feed much while guarding them.
Spiderlings
Spiderlings leave the sac after roughly 45 to 60 days. They are dull brown with only a hint of sheen, and the blue develops over the following year as they moult. They stay near the mother for a few days at most, then scatter and dig burrows of their own, which is why a healthy patch of forest floor can be pocked with dozens of small holes. Males mature in about two to three years and females in three to four.
The burrow and hunting
This is a fossorial species: it excavates a tunnel that can run well over half a metre deep, often with a turning chamber and sometimes a second entrance, and lines the whole thing with silk. Around the mouth it lays a thin mat of silk that works as a trip-line system rather than a snare — see how other spider webs catch prey by contrast. The spider waits just inside the entrance after dark, feels a cricket or roach cross the silk, lunges, bites and pulls the prey underground to feed. The burrow also buffers heat and humidity, which is why the species can live through a dry season in a monsoon climate.
Where the cobalt blue tarantula lives
Cyriopagopus lividus is a Southeast Asian species, recorded from Myanmar and from western and central Thailand, with reports from neighbouring parts of the region. It lives in tropical monsoon forest and forest edge, favouring shaded ground with soil deep and stable enough to hold a tunnel: bamboo stands, the margins of plantations, banks, and ground between tree roots.
Because it spends daylight underground and plugs the entrance in dry weather, it is rarely seen even where it is common. Most encounters happen at night in the rainy season, when females sit at the burrow mouth and mature males wander in search of them. The species' dependence on undisturbed forest floor makes it vulnerable to land clearance, and — like other showy Asian tarantulas — to collection for the international pet trade.
Are cobalt blue tarantulas venomous?
Yes, and its venom deserves more respect than the usual "harmless tarantula" line. The cobalt blue is an Old World species with no urticating hairs, and Old World theraphosids generally compensate with stronger venom. Documented bites from this group cause intense local pain out of proportion to the wound, marked swelling, and — the symptom that matters most — muscle cramps and spasms that can persist for several days, sometimes reaching muscles well away from the bite. Fever, nausea and lingering fatigue have also been reported.
No deaths have been recorded and there is no antivenom; the danger is severe, drawn-out pain rather than a threat to life. Still, treat a bite as a medical event rather than a curiosity, and take special care with children, older adults and anyone with a heart condition.
Can cobalt blue tarantulas bite?
They can, and among commonly seen tarantulas this is one of the more willing biters. Its temperament is not aggression so much as an extremely short fuse: cornered above ground with no tunnel to bolt into, it rears, slaps with the front legs and strikes quickly. It is also very fast. This is the reason experienced keepers describe it as a species to look at rather than touch, and why handling is simply not sensible.
If you are bitten: move away from the spider, wash the puncture with soap and water, apply a cold pack and keep the limb still. Expect sharp pain immediately — the fangs are long and the mechanical injury alone is significant — and be ready for cramping that may build over the following hours. Seek medical care, particularly if cramps spread, if swelling is marked, or if you feel faint or feverish. Treatment is supportive: analgesia, muscle relaxants and observation. Do not cut, suck, tourniquet or heat the wound.
Old World versus New World: the cobalt blue, like the Gooty sapphire, has no urticating hairs and a genuinely painful bite. New World species such as the pink toe and the greenbottle blue are the opposite: mild venom, but barbed abdominal hairs they kick off in a cloud when annoyed.
Ecological importance and behaviour of the cobalt blue tarantula
The cobalt blue is a nocturnal ambush predator that shapes the invertebrate life of the forest floor around it. It eats crickets, roaches, beetles, grasshoppers and other large arthropods, and big females occasionally take small frogs or lizards that stray onto the silk. A dense population removes a substantial weight of insects every wet season.
Natural predators: pompilid and spider-hunting wasps are the classic enemy, paralysing a tarantula and sealing it in the burrow with an egg. Snakes, monitor lizards, civets, mongooses and large birds also take spiders caught in the open, and the burrow itself is the main defence against all of them.
Prey–predator dynamics: almost everything about the species is built around the tunnel. It hunts from the entrance, moults, breeds and overwinters inside, and plugs the mouth with soil and silk when conditions turn hostile. A spider forced out of its burrow is a nervous, exposed animal, which is exactly when its defensive behaviour appears.
Seasonal behaviour and lifespan: activity peaks in the rains. Mature males abandon their burrows to search for females and die within months, giving a total life of three to five years, while females stay put and commonly live twelve to fifteen. Adults moult roughly once or twice a year and remain underground and helpless for days around each moult.
Relationship with humans: the species has no interest in people and is not a household pest. It is popular in captivity because of its colour, but it is a display animal — kept in deep substrate it spends most of its life out of sight — and the sustainable source is captive-bred stock rather than wild-collected spiders.
Similar tarantulas and how to tell them apart
| Tarantula | How it differs from the cobalt blue |
|---|---|
| Thailand zebra leg (Cyriopagopus albostriatus) | Same genus and country, but brown-black with clear white or cream leg striping and no blue iridescence. |
| Purple earth tiger | Another Southeast Asian relative, arboreal rather than fossorial, with a purple-bronze sheen and a tree-hollow retreat instead of a burrow. |
| Other Cyriopagopus | The genus contains several brown and striped species. Plain grey-tan body parts plus strongly blue legs point to C. lividus. |
| Gooty sapphire (Poecilotheria metallica) | Also Old World and also blue, but Indian, arboreal, and marked all over with cream-and-black fretwork the cobalt blue never has. |
| Antilles pinktoe (Caribena versicolor) | A blue-green New World tree species with a red abdomen, urticating hairs and mild venom — the safe half of the family. |
| Greenbottle blue | Blue legs again, but with a bright orange abdomen and a blue-green carapace, from Venezuelan scrub, and it spins heavy surface webbing. |
Quick facts
| Other names | Cobalt blue, blue earth tiger; formerly Haplopelma lividum. |
|---|---|
| Distribution | Myanmar and western to central Thailand, in tropical monsoon forest. |
| Habitat | Deep silk-lined burrows in shaded forest floor, bamboo stands, banks and plantation margins. |
| Diet | Crickets, roaches, beetles and grasshoppers; large females occasionally small frogs or lizards. |
| Lifespan | Females 12–15 years; males 3–5 years in total. |
| Predators | Spider-hunting wasps, snakes, monitor lizards, civets, mongooses and large birds. |
| Danger to humans | No urticating hairs; a painful bite with swelling and muscle cramps that can last days. No deaths recorded. |
| IUCN status | Not evaluated. Threatened locally by habitat clearance and wild collection. |
Did you know?
- The species name lividus means "bluish" or "leaden" in Latin. It was described as Haplopelma lividum in 1996 and moved to Cyriopagopus in 2015.
- Blue has evolved repeatedly in tarantulas using several different nanostructures, which is why so many unrelated species — Asian burrowers, Indian tree spiders and Caribbean pinktoes — hit almost the same shade.
- Because the colour is structural rather than pigment-based, a shed skin can still flash blue, and a photograph taken with flash may show a spider that looked black to the naked eye.
- A well-established burrow can be deeper than the spider is long several times over, with a wider chamber at the bottom where the animal turns around and moults.
In summary, this is a beautiful animal that is rarely seen even in its own forest. Identify it by iridescent blue legs on a plain grey-tan body, remember that it is an Old World species with no urticating hairs and a bite worth avoiding, and appreciate it where it belongs — at the mouth of its burrow, after dark.
Frequently asked questions about the cobalt blue tarantula
How big do cobalt blue tarantulas get?
Adults reach a leg span of about 11–13 cm (4.5–5 in) with a body around 5 cm long, which makes them medium-sized for the family. Females are stockier and heavier; males are lighter with proportionally longer legs. Females take three to four years to mature, males two to three.
Why do cobalt blue tarantulas look blue?
The colour is structural, not pigment. Nanostructures inside the leg hairs reflect blue light, so the spider only flashes blue when light hits it at the right angle and can look plain charcoal in dull light. The same trick has evolved independently in several unrelated tarantulas.
Is a cobalt blue tarantula's bite dangerous?
It is not life-threatening, but it is genuinely painful. As an Old World species it has no urticating hairs and relatively strong venom, and documented bites in this group cause severe local pain, swelling and muscle cramps that can last several days. No deaths have been recorded and there is no antivenom.
Does the cobalt blue tarantula have urticating hairs?
No. Urticating hairs are a New World feature, and this is an Asian species. Instead of flicking irritating bristles it relies on hiding in its burrow, on speed, on a raised threat display with the front legs, and on biting if it is cornered above ground.
Where do cobalt blue tarantulas live in the wild?
In tropical monsoon forest in Myanmar and western to central Thailand. They dig deep, silk-lined burrows in shaded soil — among bamboo, on banks, at plantation margins and between tree roots — and spend the daylight hours underground, often with the entrance plugged in dry weather.
Do cobalt blue tarantulas build a web?
Not a catching web. They line the burrow with silk and spread a thin mat of it around the entrance, which works as a trip-line system. The spider sits inside after dark, feels prey cross the silk, lunges out to bite it and drags the meal back underground.
How many eggs does a cobalt blue tarantula lay?
Typically on the order of a hundred eggs in a single white sac, sometimes several hundred. The female seals herself in the burrow, cradles and turns the sac and moves it up and down the tunnel to control its temperature. Spiderlings emerge after roughly 45 to 60 days.
How long do cobalt blue tarantulas live?
Females commonly live twelve to fifteen years. Males live far less: they mature in two to three years, stop growing at the final moult, leave the burrow to find females and die within months, so their total lifespan is three to five years. Claims of ten-year-old males are mistaken.
Are cobalt blue tarantulas suitable for beginners?
No. They are fast, defensive, and spend most of their lives out of sight in a deep burrow, so they are a species for experienced keepers who want to observe rather than interact. Any handling is a bad idea with an Old World tarantula, and a startled one bites readily.
How do you tell a male cobalt blue from a female?
After the final moult the male develops swollen pedipalps and hooks on the tibiae of the front legs, becomes leggier and slimmer, and usually loses much of the blue, turning brownish-bronze. Females stay bulkier, keep the strong blue and continue moulting for many more years.
Other spiders in the Tarantulas family
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