The daylight hours allow us to appreciate shapes and colors, but nighttime has many things to reveal to us. For this to happen, it is important that we engage and hone all of our senses, especially our ears. The varied songs of the amphibians, calling one to another from their hiding places; male capybaras marking their territories through grunts similar to barks; the howl of foxes and the singing of the owls and LECHUZAS coming from deep within the forested places, are all some of the common sounds the darkness.
Some species are only seen at night, as they are active only during the first hours of dusk. The VIZCACHAS are one example, coming out of their caves as soon as the sun begins to set, feeding on vegetation while never straying far from their places of refuge. The armadillos, also called tatús or mulitas, come out at night to hunt ants, termites, and other subterranean insects, making use of their strong claws to dig and a long, sticky, “catch-all” tongue.
The foxes take advantage of the darkness to ambush their prey, whether it be an insect, a bird, a snake, or even a young capybara. In Iberá there are three species: ZORRO DE MONTE and ZORRO GRIS, which are very similar; and the Aguará Guazú, or maned wolf, a rarely seen animal since there are very few individuals left after the intense hunting it suffered for decades.
Both species of cervids, the guazuncho, or CORZUELA, and the marsh deer, often choose to eat grass at night, especially if the day has been a hot one. The guazuncho moves in the edges of the forests, while the marsh deer prefers to patrol the edges of the route, where rainwater forms little marshes.
Due to its excellent camouflage and the quietness of its flight, the owls and LECHUZAS are a challenge to sight, but they often allow themselves to be seen while hunting or hooting. The ATAJACAMINOS or CHOTACABRAS also camouflages perfectly with the earth or with branches of trees they pose on, but their red eyes give them away when illuminated by a spotlight. In some areas near water, bats can be seen catching insects, and there is even one species which preys on small fish. It is clearly seen how plants and insects evolved together. One remarkable case is that of the DAMAS DE NOCHE and the AGUAPÉS, whose flowers open exclusively at night, attracting butterflies and moths with their strong aroma. With the first light of day, the AGUAPÉ flowers close immediately, and those of the DAMA DE NOCHE wither up a few hours later. In the spring and summer months, fireflies light up the whole of the Esteros, and these, along with the brilliant stars of the wide-open sky, without a doubt constitute one of the unforgettable sights of the excursion.
The tour takes place in an all-terrain truck, equipped with spotlights and flashlights. During the excursion, the vehicle stops and we walk in close to the animals. Although we walk in clear, firm ground, it would be ideal to wear shoes designed for uneven terrain, and long pants, as well as insect repellant and a light jacket. Depending on the time of year, the excursion gets under way between 8 and 9 PM, and lasts approximately 2 hours.