Fire-bellied Toad

• Its vividly coloured belly is an aposematic signal warning that its skin is toxic.
• It eats small aquatic and terrestrial invertebrates.
• It lives in ponds, marshes and standing water of central, eastern and south-eastern Europe.
• It has a defence with a name of its own: the unken reflex. When threatened, it arches its back, lifts its legs and displays its belly, a striking red and black, to warn that it is toxic.
• That belly is genuinely aposematic: its skin secretes bombesin and other peptides that irritate a predator's mucous membranes.
• Bombesin, first isolated from this very species, turned out to play an important role in physiology: it is a peptide that stimulates gastric secretion, and it has given rise to a whole family of peptides studied in medicine.
• Its call is a soft, repeated oo-oo that carries far on spring nights, and it is the source of its German name, Unke.
• It hybridises with the yellow-bellied toad, Bombina variegata, in a narrow, well-studied belt across central Europe, a classic model in the study of hybrid zones.

Skeleton type

Vertebrate - internal bony skeleton (amphibian)

Habitat & environment

Ponds, marshes and standing water of central, eastern and south-eastern Europe

Birth weight

A tiny tadpole on hatching

Size at birth

Tiny at hatching

Sexual maturity

1-2 years

Gestation / incubation

2-7 days of egg development (a week usually given)

Litter / clutch size

80 to 300 eggs per female, in several small groups

Lifespan in captivity

Documented record of up to 10+ years in captivity

Sources consulted: Animal Database (Fandom); Animal Diversity Web (Bombina orientalis); Animal Kingdom; The Animal Facts; Animalia.bio; Lifeamphicon; PMC (yellow-bellied toad longevity study); Reptiles Magazine