cobweb spiders vs Common Big-eared Bat

Steatoda grossa compared with Micronycteris microtis

Taxonomic Classification

Rank	cobweb spiders	Common Big-eared Bat
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum	Arthropoda (Arthropods)	Chordata (Chordates)
Class	Arachnida (Arachnids)	Mammalia (Mammals)
Order	Araneae (Araneae)	Chiroptera (Bats)
Family	Theridiidae	Phyllostomidae
Genus	Steatoda	Micronycteris
Species	Steatoda grossa	Micronycteris microtis

Evolutionary Relationship

cobweb spiders and Common Big-eared Bat share a common ancestor at the Kingdom level: Animalia. (Animals)

Conservation Status

cobweb spiders

LC — Least Concern

Common Big-eared Bat

LC — Least Concern

Physical Characteristics

Attribute	cobweb spiders	Common Big-eared Bat
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

cobweb spiders

Habitat

Typically found in terrestrial habitats from forests to deserts.

Range

Widely distributed across Africa (South Africa), Europe (29 countries), North America (Canada, United States), and South America (Ecuador).

Common Big-eared Bat

Habitat

Typically found in diverse terrestrial and aquatic ecosystems.

Range

Distributed across Colombia and Venezuela.

cobweb spiders

The false black widow (Steatoda grossa) is a cosmopolitan cobweb spider in the family Theridiidae, often mistaken for the true black widow due to its similarly dark, globose abdomen, though it lacks the red hourglass marking. Females reach 6–10 millimeters in body length and display a deep purplish-brown to nearly black coloration with faint pale markings on the dorsal abdomen. Originally native to western Europe, Steatoda grossa has spread globally through human commerce, establishing populations in Australia, New Zealand, North America, and other regions where it thrives in human structures including homes, sheds, and outbuildings. The spider constructs a persistent, tangled cobweb in sheltered corners and recesses, where it captures woodlice, ants, beetles, and other arthropods—notably targeting invertebrates that many other spiders avoid. The venom of S. grossa causes steatodism, a syndrome of localized pain, sweating, and systemic discomfort that is rarely serious but can cause significant distress. Interestingly, the antivenin produced for Latrodectus (true widow) spider bites has been shown to effectively treat Steatoda envenomations, underscoring the phylogenetic relatedness of these genera. Females produce several egg sacs during a season, each containing dozens of eggs wrapped in distinctive silken cocoons. The species is classified as Least Concern given its expanding global distribution facilitated by human activity.

Common Big-eared Bat

The common big-eared bat (<em>Micronycteris microtis</em>) is a small insectivorous bat belonging to the family Phyllostomidae, native to tropical and subtropical regions of South America. Its range includes Colombia and Venezuela, where it typically inhabits diverse terrestrial and aquatic environments including forests and riparian zones. It is classified as Least Concern on the IUCN Red List, indicating a relatively stable population. As its common name suggests, <em>Micronycteris microtis</em> is distinguished by notably large ears relative to its body size, which enhance its echolocation capabilities for detecting prey and navigating complex forest environments. The species is often associated with lowland and foothill forests, roosting in caves, hollow trees, and dense vegetation. It typically feeds on insects and may also consume small vertebrates or fruit on occasion. Biological traits of this species remain poorly documented in the scientific literature.