Mexican red-knee tarantula

This tarantula lives only in Mexico.

It lives in dry forests near the Pacific Ocean. It hides in a burrow under a log or a rock.

The Mexican red-knee tarantula lives only in Mexico, mostly in the small state of Colima and nearby parts of Michoacán and Jalisco, close to the Pacific coast. Its home is dry forest in the foothills of the mountains, with thorny bushes and trees that lose their leaves in the dry season.

It seems to like quiet, shady places under trees or bushes, sometimes near streams that flow only in the rainy season. The whole area where it lives is only about 13,000 square kilometers.

Fukushima and colleagues (2019) describe B. hamorii as endemic to Mexico, across much of Colima, the northwestern coast of Michoacán and fringes of southern Jalisco, from sea level to about 2,110 meters, with an extent of occurrence of about 13,030 square kilometers and an area of occupancy of about 8,452. It lives in subtropical dry forest in the foothills of the Sierra Madre del Sur, mostly thorn and deciduous secondary forest, preferring undisturbed areas shaded by trees or bushes and sometimes near seasonal streams.

The species overlaps with B. baumgarteni in northwestern Michoacán and with B. klaasi at the northwestern edge of Colima.

The red-knee tarantula eats bugs and other small animals.

At night, it waits at the door of its burrow. When a bug walks by, the spider catches it.

Red-knee tarantulas are night hunters. From dusk into the night, a tarantula waits near the entrance of its burrow for something to wander past.

It eats mostly animals that crawl on the ground: insects, other spiders and their relatives, and millipedes. Once in a while it may catch a small animal with a backbone. Tarantulas do not spin webs to catch food; they grab it with their strong legs and use venom to catch it.

B. hamorii is a nocturnal sit-and-wait predator that waits near its refuge entrance from dusk into the night, feeding primarily on ground-dwelling arthropods (insects, other arachnids and some myriapods) or even small vertebrates (Fukushima and colleagues 2019, after Mendoza and Francke 2017).

Like other tarantulas it builds no capture web, subduing prey with its legs and a venomous bite (Saint Louis Zoo).

Red-knee tarantulas spend the day in their burrows.

They come out at night. The grown-up males go walking to find a mate.

Red-knee tarantulas are burrowers. They often move into an old hole made by another animal, or tidy up a little space under a fallen log, a big rock or tree roots. Some dig their own.

Their burrows have no silk around the entrance, so you cannot easily tell that a spider is inside. They stay hidden in the day and come to the entrance at night to hunt. During the mating season, adult males leave their burrows to look for females.

The species is fossorial: it modifies previously excavated burrows or digs its own, often only slightly altering natural cavities under fallen logs, large rocks and large roots amid thorny brush or tall grass. Burrow entrances lack silk, giving no sign of the occupant (Fukushima and colleagues 2019, after Mendoza and Francke 2017).

In the mating season, wandering males cross roads; Fukushima and colleagues report that males are frequently found run over on highways such as Federal Highway 200, which also fragments the habitat.

There are fewer red-knee tarantulas in the wild than before.

People took many of them to sell as pets, and their forests are getting smaller. Now there are rules to protect them.

The Mexican red-knee tarantula is listed as Vulnerable by the IUCN, which means it is at risk in the wild. Many were collected to be sold as pets, and its forests are being cleared for towns, farms and roads.

All red-knee tarantulas and their relatives are protected by an international agreement called CITES, which controls trade between countries. In Mexico, some are bred in licensed centers and sold legally, so pets do not have to come from the wild.

B. hamorii is listed as Vulnerable on the IUCN Red List (global assessment by Fukushima and colleagues, 2019). Fukushima and colleagues (2019) infer declines in extent and area of occupancy, subpopulations and numbers, caused by urbanization, agriculture (especially fruit growing) and roads, and by intensive collection for the pet trade, which has likely wiped out some subpopulations. They estimate that 86 percent of the population is in fragmented, non-viable subpopulations.

All Brachypelma are on CITES Appendix II. The species is bred in Mexican wildlife management units (UMAs) and sold legally, but illegal trade continues, and one Colima subpopulation appears to supply most specimens. Protected areas such as Volcán Nevado de Colima National Park and the Manantlán Biosphere Reserve lie within its range.