cobweb spiders vs common bottlenose dolphin

Steatoda grossa compared with Tursiops truncatus

Taxonomic Classification

Rank	cobweb spiders	common bottlenose dolphin
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum	Arthropoda (Arthropods)	Chordata (Chordates)
Class	Arachnida (Arachnids)	Mammalia (Mammals)
Order	Araneae (Araneae)	Cetacea (Whales & Dolphins)
Family	Theridiidae	Delphinidae (Oceanic Dolphins)
Genus	Steatoda	Tursiops (Bottlenose Dolphins)
Species	Steatoda grossa	Tursiops truncatus

Evolutionary Relationship

cobweb spiders and common bottlenose dolphin share a common ancestor at the Kingdom level: Animalia. (Animals)

Conservation Status

cobweb spiders

LC — Least Concern

common bottlenose dolphin

LC — Least Concern

Population: ~600.0K

Trend: Stable →

Physical Characteristics

Attribute	cobweb spiders	common bottlenose dolphin
Diet	—	Carnivore
Average Lifespan	—	45 years
Average Length	—	3.0 m
Average Weight	—	300.0 kg

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 bottlenose dolphin

Habitat

Found across multiple habitat types including tropical and subtropical moist broadleaf forests, tropical and subtropical dry broadleaf forests, and tropical and subtropical grasslands and savannas, among 12 distinct biome types. Populations are also found in montane and highland environments at higher elevations.

Range

Widely distributed across Asia (Taiwan), Europe (6 countries), and South America (Colombia, Ecuador, 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 bottlenose dolphin

The most studied and recognized dolphin species, bottlenose dolphins inhabit warm and temperate oceans worldwide, from coastal shallows to the open sea. Highly intelligent with large brains relative to body size, they demonstrate self-recognition, complex communication, and social learning. They live in fluid fission-fusion societies and cooperate to herd fish. A keystone indicator species for marine ecosystem health.

Shared Countries

Both species can be found in 6 countries:

🇧🇪 Belgium 🇩🇰 Denmark 🇪🇨 Ecuador 🇵🇹 Portugal 🇸🇪 Sweden 🇺🇦 Ukraine