[6][7][8] There is an introduced population of European fire-bellied toads in Lorraine, France, over 500 kilometres (310 mi) away from their natural range in eastern Germany.

[13] However, in some areas they are recovering through human intervention, such as in Funen County, Denmark, where dozens of ponds were dug for the frogs to live and breed in, increasing their population approximately five-fold in a decade.

[4] Breeding commences once temperatures reach 16 °C (61 °F)[19] and is usually done at night time or early morning, where females will deposit up to 15 to 40 eggs depending on their size.

[citation needed] The ancestor to both species was confined to southern Europe during the Last Glacial Maximum, where B. variegata evolved in the mountains in the west (Apennine and Balkans) and B. bombina in the lowlands to the east (the steppes around the Black and Caspian Sea).

[22] As the glaciers receded, both species spread out to the rest of Europe but hybridized and competed with each other until B. bombina occupied the lowlands and B. variegata the higher altitudes.

B. bombina prefers to breed in lowland seasonal ponds, such as wet meadows and floodplains, but ones that are still close to nearby permanent waterbodies.

[23] B. bombina also spends more time confined to a waterbody compared to B. variegata, which is more terrestrial and has evolved longer legs and thicker skin to aid in their frequent migrations onto dry land.

[24][25][26] Additionally, B. variegata is unable to sing as loudly as B. bombina due to their lack of internal vocal sacs, which forces them to find other breeding ponds without the other species of fire-bellied toad.

[29] The antifungal effect of bombinins in the toads' skin makes them promising factors for incorporation into food packaging to retard spoilage.