Sirenidae, the
sirens, are a
family of aquatic
salamanders. Family members have very small fore limbs, and lack hind limbs altogether. In one species, the
skeleton in their fore limbs is made of only
cartilage. In contrast to most other salamanders, they have external
gills bunched together on the
neck in both
larval and adult states. Sirens are found only in the
Southeastern United States and northern
Mexico.