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“Mexican redknee tarantulas are famous for orange-red bands that look painted onto their dark knee joints.”
The Mexican redknee tarantula is a long-lived burrowing spider of Mexico's Pacific dry forests. It hunts insects at night, relies on urticating hairs for defense, and is Vulnerable to habitat loss and illegal collection.
Brachypelma hamoriiAraneaeTheraphosidae
Browse photographs of Mexican redknee tarantula across habitat, behavior, anatomy, and life stages.
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Core article
A closer look at habitat, diet, behavior, reproduction, and conservation.
Among the leaf litter and rocky slopes of Mexico's Pacific dry forests lives one of the world's most recognizable spiders: the Mexican redknee tarantula (Brachypelma hamorii). Dark legs banded with bold orange-red "knees," a velvet abdomen, and a patient sit-and-wait hunting style make the species easy to identify and an important wild predator of insects. Despite its fierce looks, the redknee is shy, spends daylight in a silk-lined burrow, and would rather flick itchy defense hairs or walk away than confront a human. Its biology reflects a long life shaped by seasonal dryness, careful molting, and conservation pressure from habitat loss and illegal collecting.
Mexican redknee tarantulas are arachnids in the order Araneae and the family Theraphosidae, the true tarantulas. Their genus is Brachypelma, a group of New World ground-dwellers centered on Mexico and nearby regions. For decades the famous pet-trade redknee was widely called Brachypelma smithi. Modern taxonomic work showed that the common orange-kneed animal is usually Brachypelma hamorii, while true B. smithi is a separate, more restricted Pacific species. Both can look similar, which is why older labels on photos and books may say smithi even when they show the familiar redknee now treated as hamorii. Like other theraphosids, they belong to an ancient spider radiation famous for large body size and urticating abdominal hairs rather than elaborate sticky hunting webs.
Adult Mexican redknees have a stocky body roughly 1.5 to 2.5 inches long, with a wider leg span that makes them look bigger than their body alone suggests. Eight walking legs, two pedipalps, and chelicerae with fangs form the classic spider toolkit. The signature orange-red bands sit at the leg joints ("knees"), contrasting with dark femurs and a hairy opisthosoma. Dense body hairs detect tiny vibrations through soil and silk, helping the spider sense prey and danger in the dark. Females are typically heavier-bodied; mature males become leggier and develop specialized palpal bulbs used in mating. Unlike many insects, tarantulas have no hard outer wings—growth happens only when they molt and leave an entire shed exoskeleton behind.
In the wild, Brachypelma hamorii occupies tropical dry forest and scrub along Mexico's central Pacific slope, including regions in and around Colima, Jalisco, Michoacán, and Guerrero. These seasonal landscapes swing from rainy green months to long dry periods when trees drop leaves and shade thins. Tarantulas dig or claim burrows under rocks, roots, and litter, lining retreats with silk for footing and humidity control. They are terrestrial ambush hunters rather than canopy web-builders. Outside the natural Mexican range, the species is common in legal captive care, but wild populations remain tied to intact dry-forest patches that are increasingly fragmented by farming, roads, and coastal development.
Mexican redknee tarantulas are carnivores. At night they wait near the burrow mouth for crickets, beetles, grasshoppers, and other small arthropods. When prey steps within range, the spider lunges, seizes it with fangs, and injects venom that quickly subdues a small invertebrate meal. Digestive fluids then help turn soft tissues into a liquid the spider can ingest. They do not need dramatic chases or huge sticky webs; patience plus vibration sensing is enough. In healthy dry forests, this hunting reduces insect numbers and turns small prey into nutrients that return to the soil web when the spider itself is eaten or decomposes.
These tarantulas are solitary. Outside brief mating encounters, each spider usually keeps its own burrow and hunting space. Daytime is for hiding; nighttime is for waiting and wandering short distances. When threatened, a redknee may rear slightly, raise front legs, or flick urticating hairs from the abdomen—tiny barbed hairs that can itch skin and eyes. Biting people is uncommon because the spider prefers retreat. Molting is a high-stakes quiet behavior: before shedding, appetite drops and the spider becomes still, later emerging pale and soft until the new exoskeleton hardens. That caution and stillness are why calm observation works better than forcing contact.
After mating, a female produces a silk egg sac that may hold a few hundred eggs. Spiderlings hatch inside the sac and later disperse to begin solitary lives. Growth is measured in molts: each shed increases size and gradually strengthens the bright knee bands. Females can live many years—often well into their teens or longer—while adult males usually have only one breeding season after their final molt. Because females mature slowly and invest heavily in each brood, populations cannot bounce back quickly if too many adults are removed from the wild.
(Population and conservation trend data sourced from the IUCN Red List of Threatened Species)
Brachypelma hamorii is listed as Vulnerable. Wild numbers are pressured by conversion of dry forest to agriculture and settlements, and by illegal collection for the international pet trade. The genus is also regulated under CITES Appendix II, which controls cross-border trade. Responsible captive breeding reduces demand for wild-caught animals, but only habitat protection—leaving burrow-rich forest and scrub intact—can keep free-living Mexican redknees in place. Clear public information about their shy behavior can also reduce unnecessary killing based on fear.
Mexican redknee tarantulas are famous for orange-red bands that look painted onto their dark knee joints.
When worried, they can flick tiny itchy hairs from the abdomen instead of biting first.
Females can live for decades, while adult males usually live only one mating season.
Scientists now call the common pet-trade Mexican redknee Brachypelma hamorii; older books often said B. smithi.
They spend daylight hours in silk-lined burrows and come out mostly at night.
A tarantula must molt—shed its old exoskeleton—to grow bigger and repair damage.
Select a question to reveal the answer.
It is a colorful ground-dwelling spider from Mexico's Pacific dry forests. Its scientific name is Brachypelma hamorii, and it is known for bright orange-red bands on its legs.
They live in tropical dry forest and scrub along Mexico's central Pacific slope, especially in states such as Colima, Jalisco, Michoacán, and Guerrero.
They are carnivores that hunt insects and other small arthropods, including crickets, beetles, and grasshoppers.
No. They are shy. Their mild venom is used for small prey, and they usually prefer to flee or flick itchy hairs rather than bite people.
For many years the popular Mexican redknee was called Brachypelma smithi. Taxonomists later showed the widespread redknee is usually Brachypelma hamorii, while true B. smithi is a separate species.
Females can live 15 to 30 years. Males mature later and usually live only a short time after becoming adults.
Young tarantulas are called spiderlings. They hatch from a silk egg sac and molt many times as they grow.
They are listed as Vulnerable. Habitat loss and illegal collecting for the pet trade are major threats, so legal captive breeding is important.
No. They use silk to line burrows and wrap egg sacs, but they do not build large sticky hunting webs. They sit-and-wait for prey near the burrow.
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