The term “tarantula” refers to the relatively large and often hairy members of the family Theraphosidae. There are over 900 species of tarantula, and tarantulas can be found on every continent in the world other than Antarctica. The goliath bird-eating spider is the largest tarantula in the world, and one of the most well-known. Its leg span can reach up to 11 in (28 cm) in diameter!
All tarantulas are venomous, though in most cases the only symptom a human will face after being bitten by a tarantula is pain equivalent to that of a bee sting. Tarantulas only bite non-prey items as a last resort, though. Their first instinct is to run and hide. If this fails, some tarantulas have urticating hairs on their abdomens which can be flicked off by the spider’s back legs. Hairs that get stuck in the eyes and nose of a threat cause irritation, giving the tarantula a window to escape.
In the wild, tarantulas will, generally prey on insects, though small mammals are targeted if they look manageable to the tarantula. As its name suggests, the goliath bird eating spider has even been known to prey on small birds!
Information on the Mexican red knee tarantula can be found below. This species has been highlighted here in part due to its stunning beauty, but mainly because it is a prime example of a species that has seen drastic population declines due to the pet trade. The relatively docile nature of this spider coupled with its bright red-orange markings, has made it the target of unsustainable harvesting from the wild.
Distribution: Dry forests in the foothills of the Sierra Madre del Sur Mountains, Mexico.
Diet in the Wild: Invertebrates and some small vertebrates
Diet at Caldwell Zoo: Crickets, pinky mice
IUCN Red List Status: Near threatened, population decreasing
Threats: Primarily overharvesting for the pet trade and for use in traditional medicines, though habitat loss and increased frequency of severe weather events have also had an effect on the population.
The Mexican red knee tarantula is a ground-dwelling species, making its home in places such as small cavities in the ground or under logs. They do not leave any silk near the entrance of the burrow, making burrows difficult to identify
Mexican red knee tarantulas are sit-and-wait predators, waiting by the entrance to their burrows in the evening and throughout the night for unsuspecting prey to wander into striking distance.