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How do some tree frogs use their heads to seal water-filled plant spaces or tree holes?
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frog and toad
The natterjack toad (Bufo calamita) lives in northern Europe.
Certain arboreal frogs within the family Hylidae have evolved specialized structural modifications to survive dry periods. These frogs possess a head modified into a bony casque, or helmet, where the skin is co-ossified with the underlying bone.1
This hardened head structure allows the frogs to act as a living plug. By positioning themselves at the constricted base of bromeliads or within tree holes, they effectively seal these water-filled cavities. This behavior enables the frogs to survive the dry season by protecting and utilizing the small amount of moisture trapped within the cavity.1