Carnivorous Plants, Black Widows, and 1,000 Lakes: Meet the Famous Brazilian Dunes
By Ramy Maalouf | November 29, 2025
The Lençóis Maranhenses National Park in northeastern Brazil is a remarkable sight, often aptly described as the "Brazilian desert with a thousand lakes." But calling it a desert is, scientifically speaking, a bit of a misnomer. This region receives between 1,200 and 1,600 mm of rain annually—more than London or Berlin.
Imagine miles of white sand dunes, sculpted by the wind, interspersed with countless freshwater lagoons that appear like magic with the seasonal rains. The secret to this phenomenon lies underground: a layer of impermeable rock beneath the sand prevents the rainwater from draining away, creating these crystal-clear pools. It’s a unique landscape, and last year, I had the chance to explore it during a family vacation.
As a field botanist and naturalist, my holidays often involve a good deal of wandering off the beaten path, camera in hand, looking for the plants and animals that call these places home. We explored different access points to the park, including the areas around Santo Amaro do Maranhão, Atins, and Barreirinhas, each offering a slightly different perspective on this vast natural wonder.
The Lençóis, despite its seemingly barren appearance at first glance, quickly revealed a surprising amount of life adapted to its extreme cycles of flood and drought.
 Sunset near Santo Amaro |  Vegetation in the horizon |  Wet lands full of life |
|---|---|---|
 Dunes and vegetation |  Desert shades |  Lanes and shapes |
 Atins |  Sunset |  Crossing the river near Barreirinhas |
 Sand pyramids |  The view from the other side of the dunes |  Home for many plants and insects |
 A person is very small in this place |  Panoramic |
Life in the Lagoons: The Green Hunters
The temporary freshwater lagoons that form between the dunes are central to the ecosystem here. Because the sandy soil is so nutrient-poor, many plants have evolved fascinating survival strategies to supplement their diet—most notably, carnivory. I was particularly interested in finding these "green hunters," and the Lençóis didn't disappoint.
The traps
Drosera sessilifolia (Sessile-leaved Sundew): This small, rosetted annual was a highlight. Its reddish leaves are covered in sticky, glandular tentacles. It thrives in the sandy margins of the lagoons, gleaming in the sun to attract unsuspecting insects. Once stuck, the insect is slowly digested, providing the nitrogen the plant can't get from the soil.
Utricularia cornuta (Horned Bladderwort): I also found this beautiful bladderwort, easily spotted by its distinctive yellow flowers rising from the wet substrate.
Scientific Note: While they look delicate, plants in this genus possess the fastest trapping mechanism in the plant kingdom. Their underground "bladders" are vacuum traps that suck in tiny prey (like nematodes or protozoa) in less than a millisecond—faster than the blink of an eye! [Insert Photo: Utricularia cornuta]
The floating beauties
Floating on the surface of some lagoons, I found Nymphoides humboldtiana (Water Snowflake). It adds a touch of delicacy to the water with its white, fringed flowers.
ID Tip: It is often confused with the invasive N. indica, but N. humboldtiana is native to the Americas. Taxonomists distinguish them by their seeds—humboldtiana lacks the small bumps (tubercles) found on its cousin's seeds.
Other interesting botanical finds included the bright yellow flowers of Xyris jupicai, the often overlooked Burmannia capitata, and flowering herbs like Schultesia guianensis and Comolia villosa. The stability of the dunes themselves often relies on grasses and sedges from tribes like Andropogoneae and Paniceae, along with Eleocharis geniculata, which bind the shifting sands with their root systems.
The animal life, while perhaps less immediately obvious than the sweeping dunes, was certainly present for those who looked.
The Speedsters of the sand
On the hot sand, Tiger Beetles like Cylindera suturalis were active. These beetles are voracious predators and incredibly fast runners. In fact, they run so fast that their brain cannot process visual images quickly enough to keep up, causing them to go temporarily "blind" while sprinting—which is why they often stop abruptly to reorient themselves before chasing their prey again.
Bridlife
Bird sightings included the Athene cunicularia (Burrowing Owl), often seen standing sentinel near its burrow entrances in the sand, and the Cathartes burrovianus (Lesser Yellow-headed Vulture) patrolling overhead. We also spotted the vibrant Aratinga jandaya (Jenday Parakeet) and the Chroicocephalus cirrocephalus (Grey-headed Gull), a reminder of how close the ocean lies to these freshwater bodies.
A Curious Case: The Unidentified Latrodectus
One of the most intriguing and puzzling finds of the trip was a population of black widow spiders belonging to the genus Latrodectus. I found them in vegetation near the dunes, but the encounter was unique: while I didn't see them anywhere else in the park, I found dozens of individuals concentrated in just one specific location.
While clearly a widow spider, this specimen has defied identification. It does not fit the standard descriptions for the species usually recorded in the region. I have shared these photos on citizen science platforms like iNaturalist, posted in specialized arachnology forums on Facebook, and even consulted with enthusiasts directly, yet no one has been able to provide a conclusive identification.
Description:
The spiders were striking and distinct from the common Brown Widow (L. geometricus) or the typical "Flamenguinho" (L. curacaviensis).
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Coloration: They possessed a glossy, jet-black cephalothorax and abdomen.
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The Pattern: The dorsal (back) markings were vivid red against the black body. The pattern consisted of a central longitudinal jagged stripe—almost like a series of connected diamonds—running down the spine.
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The Four Dots: What made these specimens truly unique were four distinct, isolated red dots on the sides of the abdomen (two on each flank). These spots were not connected to the central stripe, a feature that seems to stump the experts.
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Ventral Side: They displayed the classic red hourglass mark on the belly, which appeared thick and bold against the dark abdomen.
For now, this spider remains a "naturalist's puzzle." It could be a highly localized color morph of a known species, or perhaps something that requires further scientific study. It serves as a reminder that even in a popular destination like the Lençóis, there are still mysteries waiting in the sand.
Reflections on a Sandy Expanse
The Lençóis Maranhenses is a place that grows on you. It’s more than just sand and water; it’s a dynamic system where life has found remarkable ways to adapt, from the millisecond-snatch of a bladderwort to the specialized survival skills of the Latrodectus spider.
Every plant and animal I managed to photograph is a small piece of that larger story. For a naturalist, it’s these direct observations the unique flora, the interesting fauna, and the joy of solving a taxonomic puzzle that make a trip memorable. It’s a landscape that certainly left an impression and one that I’m sure still has many more discoveries to offer.
Appendix 1: Documented Plant Species