Common Spadefoot
Pelobates fuscus
The Common Spadefoot is a stout amphibian reaching about 8 cm in length, primarily known for its secretive, burrowing lifestyle. It is characterized by vertical slit pupils and hardened, sharp-edged metatarsal tubercles on its hind feet, which allow it to burrow backwards rapidly into loose soil. When threatened, it emits a secretion that smells strongly of garlic, giving the species its common name. A remarkable feature is its tadpoles, which can reach lengths of up to 18 cm, significantly exceeding the size of the adults.
Details
Identification
Vertical slit pupils, light-colored metatarsal tubercles (spades) on heels, smooth skin with variable dark spots, garlic odor.
Social behavior
Solitary outside the breeding season; males emit calls underwater during the reproductive period.
Diet
Adults feed on invertebrates such as insects, spiders, earthworms, and snails; larvae consume algae, detritus, and microorganisms.
Hunting strategy
Active foraging and ambush hunting on the soil surface during the night.
Spawning substrate
Vertical structures such as aquatic plant stems or branches in permanent stagnant water bodies.
Overwintering
Overwintering buried deep in the soil (up to 1 meter deep) in self-excavated burrows.
Ecology
Ecological role
Important predator of soil invertebrates; tadpoles influence algal biomass in water bodies.
Natural predators
Grass snake, herons, storks, birds of prey, martens, polecats, and fish (for eggs/larvae).
Competitor species
Other amphibian species such as the common toad or European green toad when using spawning sites.
Ecosystem service
Natural pest control by consuming agriculturally relevant insects and snails.
Threats
Intensification of agriculture, use of pesticides, loss of small water bodies, lowering of groundwater levels.
Scientific profile
Profile
Distinguishing features
Key features include the vertical slit pupil (cat-like) and the large, sharp-edged, yellowish metatarsal tubercle (spade) on the hind feet. The frontal callus between the eyes is distinctly arched. Unlike true toads, parotoid glands are absent.
Role in food web
Adults are important predators of small invertebrates; larvae influence algal biomass. The species serves as prey for various birds, snakes, and mammals.
Protection & threats
Main threats
Intensification of agriculture (pesticide use, fertilization, loss of fallow land), groundwater lowering, habitat fragmentation due to road construction, loss of breeding ponds through infilling or fish stocking.
Population trend
Strongly declining in large parts of Central Europe; in Germany, usually classified as 'vulnerable' (3) or 'endangered' (2) on the Red List.
Conservation measures
Creation and ecological optimization of breeding ponds (fish-free), preservation of sandy soil structures, promotion of organic farming, biotope connectivity through corridors.