Cat-calling won’t work for this little toad. Male pumpkin toadlets (Brachycephalus ephippium) produce a vocal chirp that neither they nor females of the species can hear. Both in the field and in the lab, researchers have been able to demonstrate that these toadlets don’t respond to their calls or artificially produced vibrations of the same frequency. The reason seems to be that their ears lack important components necessary for picking up the high frequencies they produce. It is thought that the behavior is vestigial, meaning that it once served a purpose during their evolutionary history but no longer does. The chirping is performed along with a swelling of the bright orange throat sac, a visual cue that females of the species do still respond to.
Sketch contributed by Amelia Munson. Fact contributed by Adrian Perez.
Goutte, S., Mason, M.J., Christensen-Dalsgaard, J., Montealegre-Z, F., Chivers, B.D., Sarria-S, F.A., Antoniazzi, M.M., Jared, C., Sato, L.A. and Toledo, L.F., 2017. Evidence of auditory insensitivity to vocalization frequencies in two frogs. Scientific Reports, 7(1), pp.1-9.