The mating call of hybrids of the fire-bellied toad and yellow-bellied toad (Bombina bombina (L.), Bombina v. variegata (L.), discoglossidae, anura).

Male hybrids obtained by crossing Bombina bombina with Bombina v. variegata displayed calling behavior when treated with hormones at the age of about 12 months. The mating calls of the hybrids are intermediate with respect to rate, duration, inter-call interval, and fundamental frequency between the calls of the two purebred species.