While the animals represented could embody specific deities, the goddess Tawaret as a hippopotamus or Sobek as a crocodile, the absence of other motifs, attributes or an inscription suggest that they function here as general apotropaic symbols. The hippopotamus and the crocodile are common Egyptian animals, living in and along the Nile. Through this close association with the river, and thus with life and the annual flooding, they were associated with renewal and regeneration.
To discover more about amulets in the Ancient Egyptian world, please visit our relevant post: Amulets in Ancient Egypt.