Salem Ornamental Tarantula (Poecilotheria formosa)

Physical description and identification

The Salem ornamental is a flattened, tree-dwelling tarantula of the genus Poecilotheria, endemic to the Eastern Ghats of southern India. Like its relatives it is built to disappear: a low carapace, legs held splayed outwards rather than tucked beneath the body, and a dorsal pattern that reproduces the texture of lichen on bark.

Descriptions that call it simply "black and white" undersell it. The ground colour is a mosaic of grey, cream, buff and black, and the legs carry a soft violet cast that is obvious on a freshly moulted adult and fades as the setae wear. As in every ornamental, the diagnostic detail is underneath: the front legs carry bold yellow bands on black, invisible while the spider walks and shown only when it rears.

Adults

• Size: a medium to large member of the genus, with a diagonal leg span of 14–16 cm (5.5–6.3 in) and a body length of around 6 cm in adult females. Males are lighter, with longer legs in proportion to the body.
• Colour: grey, cream and black bark mosaic with a violet wash on the femora. The abdomen carries a pale central band edged by dark chevrons.
• Speed: even among ornamentals this is a notably quick species, capable of crossing a trunk faster than a person can track it.
• No urticating hairs: an Old World tarantula, so unlike a New World species such as the Mexican red knee it cannot flick barbed abdominal hairs at a threat. Camouflage, speed, display and the fangs are its whole defence.
• Sexes: mature males are slimmer with swollen palpal bulbs and tibial hooks on the front legs, and usually lose contrast after the final moult; females stay heavier and brighter for many years.

Eggs and egg sac

The female builds her egg sac from dense silk inside the retreat she has spun in a tree cavity and guards it there rather than carrying it. Clutches run to roughly one to two hundred eggs and take several weeks to develop.

Spiderlings

Older accounts say the young dig their own burrows. That is not right for this genus: Poecilotheria is arboreal at every stage, and spiderlings take up narrow crevices in bark, cavities and sometimes ground-level cracks, lining them with silk rather than excavating anything. They are reclusive, hiding almost continuously between moults, and mature at about two years.

The web and hunting

The Salem ornamental builds no capture web. What it does build is a dense silk tube inside a hollow trunk or behind loose bark, with silk lines running out across the surrounding surface that carry vibration back to the spider. It waits at the entrance after dark, crosses the bark in a fraction of a second when prey lands, bites, and drags the meal back inside. See our guide to spider webs for how this differs from a snare.

Where the Salem ornamental tarantula lives

Poecilotheria formosa is endemic to southern India, recorded from the Eastern Ghats in the broad band between Salem in Tamil Nadu and the Tirupati hills in Andhra Pradesh. The common name comes from that first locality.

The habitat is tropical dry and moist deciduous hill forest, plus the older trees left in plantations and village groves. The requirement, as for the whole genus, is a standing tree with a cavity: hollow trunks, heartwood splits and gaps behind loose bark. It is occasionally found in outbuilding timbers at the forest edge.

Its range is modest and fragmented, and the mature hollow-bearing trees it depends on are the first to go when hill forest is cleared or replanted. The genus was placed on CITES Appendix II in 2019, which regulates international trade, and Indian Poecilotheria including this species are listed on the IUCN Red List following the assessment of the group; habitat loss remains the dominant threat.

Is the Salem ornamental tarantula venomous?

Yes, and it is one of the tarantulas where venom genuinely matters. The general rule that tarantula venom is of little consequence to people does not hold for Poecilotheria, which clinical toxicologists treat as a medically significant genus, and P. formosa is among the species with documented human cases.

The pattern is consistent. Sharp pain at the bite is followed hours later — often after the initial pain has eased — by severe cramping in large muscle groups such as the calves, thighs, chest wall and abdomen, usually accompanied by sweating, headache and malaise. The spasms come in waves and can persist for days. Some cases have required hospital admission for pain control and observation.

The reassuring side is equally clear: there has never been a recorded death from a bite by any species in this genus, no antivenom exists and none is needed, and healthy adults recover fully. The venom does not destroy tissue.

Can the Salem ornamental tarantula bite?

It can, and its speed is the reason bites happen. Faced with a threat the spider's first choice is to run — into the retreat, round the trunk, or off the tree entirely. Its second is to rear into a threat display with the fangs and the banded undersides of the front legs raised. Only when both fail does it strike, and strikes are typically repeated. With no urticating hairs to serve as a warning stage, the gap between a startled ornamental and a bitten hand is very short.

In the pet trade this is an advanced arboreal species, kept in a tall ventilated enclosure with a vertical cork retreat and never handled. Handling is not part of responsible husbandry for any Old World tarantula.

Ecological importance and behavior of the Salem ornamental tarantula

This is a nocturnal ambush predator tied to a single tree cavity for most of its adult life. It spends daylight hours wedged in its silk tube and comes to the entrance at dusk, resting its front legs on the silk lines that run over the bark outside.

Diet: large insects of the trunk and canopy — cockroaches, crickets, grasshoppers, moths and beetles. Large females occasionally take a small gecko or frog, but such records are exceptional. The long feeding lists in older profiles reflect what keepers offer, not what the spider eats in a hill forest.

Natural predators: spider-hunting wasps, monitor lizards, snakes, civets, mongooses and insectivorous birds. Wandering mature males are by far the most vulnerable; a female deep inside a hollow is hard to reach.

Ecological role: a resident female removes large insects from one tree year after year and in turn feeds the wasps and vertebrates of the same forest.

Seasonal behaviour: males mature at around two years, leave their retreats and wander in search of females, usually around the monsoon, and rarely survive a year past that final moult. Females stay put and breed across many seasons, living twelve years or more.

Relationship with people: encounters are uncommon and the spider never seeks one out. The sensible precaution in its range is not to put an unprotected hand into a tree hollow, a woodpile or a dark roof space.

Similar spiders and how to tell them apart

Quick facts

Did you know?

• The British zoologist Reginald Innes Pocock described this species in 1899 and chose the epithet formosa, Latin for beautiful — which is where the alternative name "beautiful parachute spider" comes from.
• "Parachute spider" is not decorative. A startled ornamental drops from its tree with all eight legs spread and uses its flattened body to slow and steer the fall.
• The bright bands under the front legs are a signal, not camouflage. Lowered they cannot be seen at all; raised in the threat posture they turn a hidden spider into an obvious one in a single movement.
• Several individuals of different sizes are sometimes found in one hollow tree — a supply of separate crevices rather than social behaviour, since ornamentals hunt alone and will cannibalise one another.

In summary, the Salem ornamental tarantula is a beautiful and genuinely formidable tree spider of the Eastern Ghats: small-ranged, superbly camouflaged, without urticating hairs, extremely fast, and carrying a bite that has put people in hospital. Look, photograph, and keep your distance.