In a private wildlife research facility and rhea farm of Argentina, artificially incubated eggs of putative hybrid origin between the Greater Rhea (Rhea americana) and the Lesser Rhea (R. pennata) hatched and gave birth to healthy chicks. Molecular genotyping confirmed the hybrid origin of these chicks which were molecularly sexed as females (Delsuc et al., 2007).
Delsuc, F., Superina, M., Ferraris, G., Tilak, M. K. & Douzery, E. J. P. (2007). Molecular evidence for hybridisation between the two living species of South American ratites: potential conservation implications. Conservation Genetics 8, 503-507.