Contributions to Zoology, 86 (4) – 2017Jacques J. M. van Alphen; Jan W. Arntzen: The case of the midwife toad revisited
Unexplainable aspects in Kammerer’s experiments

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It is unclear why a rise in temperature would have induced the midwife toads in Kammerer’s experiment to move to the water basin and spend most of their time in the water. Kammerer (1909:462) says “… it is the unusually high temperature that forces them to spend much more time in the water…” and he explains this by saying that ”... animals that have to endure disagreeable temperatures go into the water to cool themselves …”. This cannot be true for his experiments, as the water in the basin must have had the same elevated temperature as the room and the terrarium. Later, Kammerer (1919:325) adds a different explanation: “Alytes, as most nocturnal amphibians, likes it cool, and looks for a cool place and shelter against desiccation of the skin in the water as soon as the air becomes too warm.” (italics are ours). It is unlikely that the elevated temperature would have caused a low air humidity, as there was a water basin in the terrarium and there was only little ventilation. Moreover, breeders report difficulties in breeding Alytes obstetricans (Laurenti, 1768) indoors even under circumstances mimicking the natural world. The Iberian congeneric A. cisternasii Boscá, 1879 and A. muletensis (Sanchiz & Adrover, 1977) appear easier in this respect but were not available to Kammerer (Tonge and Bloxam, 1989; Bloxam and Tonge, 1995; Michaels et al., 2016).