How does a South American lungfish respond to water shortages?

In response to water shortages, the South American lungfish (Lepidosiren) burrows into the mud to survive until water returns. During these periods of drought, it constructs a subterranean cocoon that maintains a connection to the surface via a thin tunnel.12

Once inside this environment, the lungfish enters a state of estivation, during which its metabolism, respiration, and heart rate drop to low levels. This physiological adaptation allows the fish to remain viable without food or water for extended periods, lasting months or even years. While the African lungfish also utilizes this burrowing behavior, it additionally forms a protective mucous sheath, a feature not present in the South American species.21