The genus Proamphiuma from the Cretaceous is the earliest known member of the family, and closely resembles the modern species aside from less elaborate vertebral structures.

[7] Amphiumas also have a lateral line visible on the sides of their bodies, which is capable of detecting movement and is used in aid of hunting.

[citation needed] Female amphiumas lay their eggs in wet mud, and then remain coiled around them for about five months, until they hatch.

Hunting and eating habits have been observed to be very similar to that of the axolotl, including the sucking in of food by their stomachs with vacuum force.

When a pair is formed they wrap their bodies around each other, and the male will transfer a spermatophore directly into the female cloaca (cloacal apposition).

[citation needed] Amphiuma are primarily carnivorous amphibians that consume crayfish, insects, and other small invertebrates.

Similar to many salamanders, the amphiuma has two distinct forms of suction feeding procedures: stationary and strike.

[14] strike suction is rapid motion where the mouth opens and buccal expansion occurs synchronously leading to a quick attack.

[14] These two feeding habits give the amphiuma the ability to have a larger variety of food (live or dead).

But amphiuma's narrow jaw makes it harder for them to fully consume large prey such as crayfish or mice.

[16] Amphiuma possess relatively ancestral forms of lungs compared to some of the other groups of salamanders that live terrestrially today.

Pressure gradients for respiration occur in two different locations, the buccal cavity/nares (mouth and nostril) region, and in the lungs of the amphiuma.

Without inhaling, amphiuma repeat the process, exhaling a second volume of air that allows them to completely empty their lungs.

[21] Generally, males have been found to possess larger bodies and longer heads compared to the female sex, which normally is indicative of male-male combat observed within the population.