These are crawfish holes. I took the pictures yesterday.

If they aren't already, crawfish should be the state crustacean of Louisiana.

When we were kids, there was water in the ditch, oh, maybe an inch or two. We'd tie a bit of bacon or cheese to the end of a thread, and fish for them. (Never worked in the mud structures.) It took a light hand to get a crawfish out of the water and into the bucket.

Sometimes, we'd feel a heavy unyielding tug, as though the thread were caught in the mud in the ditch. Then the thread would snap, and we'd come up with nothing. But once, I pulled very slowly. A dark, smooth-bodied creature with a big mouth clamped to the string slid from the muck. We screamed. I let go.

We later learned it was a siren.

Here is a description of sirens from wikipedia:

"The sirens are a family of aquatic salamanders. Family members have small front extremities and lack hind limbs.[citation needed] In one species, the skeleton in their forelimbs is made of only cartilage. Sirens are limited to the North American continent.[citation needed] In contrast to most other salamanders they have external gills bunched together on the neck in both larval and adult states.

"Sirens are quite distinct from other caudates, hence they form their own suborder Sirenoidea. Sometimes they are even referred as a completely distinct order (Meantes or Trachystomata). Genetic analysis confirms that sirens are not closely related to any other salamander group.[citation needed] Many of their unique characteristics seem to be partly primitive and partly derivative.

"They are not primitive as one may think, but degenerated.[citation needed] The larval gills are small and functionless at first, and only adults have fully-developed gills in form and function. Because of this, it is most likely sirens have evolved from a terrestrial ancestor that still had an aquatic larval stage. Like amphiumas (congo eels), they are probably able to cross land on moist nights through wet grass.

"Except for some patches of small teeth on their palate and on the splenial bone on the inner side of their lower jaw, their mouth has lost all dentition and has been replaced with a horny sheath that resembles a beak. Sirens feed mainly on worms, small snails, shrimps, and filamentous algae. [I think they oughtta add crawfish here.]

"If the conditions of a water source are unsuitable, a larvae will shrink its gills to mere stumps, and may not function at all. They are also able to burrow into mud of drying ponds and become entombed, covering themselves with a cocoon. In this period they breathe with small but functional lungs..."