Why are tarantulas out by the thousands on Texas grasslands and trails this summer?
During the summer, thousands of tarantulas make their way through Texas roads, trails and backyards, looking for a mate.
The annual tarantula migration started in May and will last through July. Tarantulas can be observed as late as early October in Central Texas.
“They are relatively common throughout Texas and their large size makes them quite recognizable,” says Texas A&M’s Texas insects field guide. They’re the heaviest spiders and are about 1.5 inches long.
What to know about Texas tarantulas
There are 14 species of tarantula found throughout Texas, per the National Park Service, though it takes an expert to differentiate them. The head-thorax and legs are a dark brown and the abdomen a brown black.
In Texas, tarantulas are especially common in grasslands and semi-open areas. They shelter under burrows, natural cavities under logs or stones, spaces under loose bark of tree trunks and old rodent burrows. You can sometimes identify a tarantula shelter through webbing with a few lines of silk on the ground in front of the shelter used to detect passing prey.
Tarantulas can climb and usually remain in the burrow waiting for prey to come by, though sometimes they can be found a few meters nearby. Tarantulas feed on crickets, June beetles, ground beetles, grasshoppers, cicadas and caterpillars.
Female tarantulas tend to live longer than the males and can lay between 100 to 1,000 eggs in a web constructed like a hammock. Texas tarantulas tend to remain in their burrows, according to NPS. Tarnatula eggs hatch in 45 to 60 days, TAMU’s field guide says.
Spiderlings hatch in July or later in the year. After they leave the egg sac, they stay with the females for about three to six days before beginning their own burrows. Many fall prey to other spiders or predators. A female tarantula can live over 25 years, while males rarely live more than three months after maturity, according to TAMU.
Are Texas tarantulas dangerous?
“One of the most spectacular spider events in Texas occurs for a few weeks each summer when male tarantulas actively wander apparently seeking females,” says the TAMU field guide. “This phenomenon is not well understood and may be related to migration more than mating.”
Seeing the spider in Texas during the summer may be alarming because of its large size and hairiness. While tarantula bites are painful because they have sharp fangs, they are not harmful to humans and the venom injected is not dangerous. Tarantulas also defend themselves through urticating hairs on the abdomen, which can cause eye or skin irritation.
