Fauna
Arachnid

Southwestern Trapdoor Spider

Eucteniza relata

Southwestern trapdoor spiders live secretive, subterranean lives inside silk-lined burrows capped with a camouflaged wafer lid. Females rarely emerge from these shelters, relying on subtle ground vibrations to detect passing insects before lunging out to seize them. Wandering adult males are typically encountered above ground during warm autumn nights, driven by seasonal rains to seek mates.

BurrowingNocturnalArachnid
Southwestern Trapdoor Spider reference1 / 7
(c) Juan Cruzado Cortés, some rights reserved (CC BY-SA), uploaded by Juan Cruzado Cortés · cc-by-sa
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Not EvaluatedConservation statusIUCN Red List categoriesLCNTVUENCREWEXNot Evaluated — not placed on the risk ladderRed List categories, explained →
Key facts
Diet & preyGround beetles, Crickets, Millipedes
Predators
  • Pompilid spider wasps
  • Centipedes
  • Small rodents
ThreatsHabitat loss from urbanization, agricultural expansion, and vehicle traffic
HabitatsArid shrublands, desert grasslands, chaparral, and oak woodlands
Life span5 to 20 years (females live significantly longer than males)
Classification
  1. OrderAraneae
  2. FamilyEuctenizidae
  3. GenusEucteniza
  4. SpeciesEucteniza relata
Range & activity
Range data is not available yet.
Safe observation
Interaction riskLow
  1. Low
  2. Moderate
  3. High
  4. Very high
Why interaction risk is low
Large fangs can deliver a painful mechanical pinch if mishandled; observe safely without touching.
Why it is dangerous
Possesses prominent chelicerae that can mechanically puncture human skin, causing localized swelling and pain similar to a mild bee sting.
How to recognize a risky encounter
Heavy-bodied, glossy dark brown to reddish-brown spider with stout legs, often seen walking slowly along the ground at night.
What to do
Do not pick up by hand; if one enters a building, guide it into a cup using a stiff piece of paper and release it outside.
Responsible observation
  • Night Observation: Scan sandy banks and open scrub with a headlamp to spot wandering males.
  • Burrow Etiquette: Avoid probing or digging out burrows, which destroys their fragile silk architecture.
Related species
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