“In Brazil, an invasion of several hundred or even thousands of crocodiles on a beach, and the local population is in panic” proclaims in a tweet the American radio presenter Ken Rutkowski. And to illustrate his point, he publishes a short video showing several hundred saurians basking in the sun on the sandy banks of a river (see his tweet below). Impressive images for those who are not used to encountering these animals elsewhere than in zoos. They have, in reality, nothing usual or worrying for the inhabitants of the place. It is also in a calm voice that the author of the video (who is not Ken Rutkowski) simply comments: “For you who have never seen a jacaré…”, before specifying the place from where he films: the city of Corumbá, in the Pantanal. A city in the heart of South America, located on the border between Brazil and Bolivia.
In Brazil, an invasion of crocodiles that have flooded one of the beaches by several hundred or even thousands, and the local population is panicking pic.twitter.com/3xnkqHdoyl
—Ken Rutkowski (@kenradio) September 15, 2022
Gatherings motivated by lack of water and food
As for the many animals that can be seen on this beach, they do not belong to the crocodilian family, as the author of the tweet asserts, but to that of the alligatorids. The latter are distinguished from crocodiles, among other things, by a wider and stockier jaw, in the shape of a “U”. And they are also smaller. As the author of this video reminds us, Brazilians call these animals “Jacarés”. A term from the ancient indigenous Tupi language “jaeça-karé”, which means “one who has eyes on the side”.
About 6 species of these alligatorids are found in South America. The animals that appear in this video were identified as “Pantanal Jacarés” (Caiman yacare) by Zilca Campos, a Brazilian researcher specializing in these reptiles, for the public agricultural research company Embrapa. A species that has the particularity of migrating in large bands to hunt, or to reproduce (between January and March).
No danger to humans
“Such gatherings of animals are common, mainly in times of drought. Especially since the Pantanal has suffered from a severe lack of water since 2019” explains the researcher to Science and Future. Typically, these gatherings occur between September and November.”. Because during this dry period, the water levels drop and the Jacarés gather around some riverbeds still in water, in search of food. “This is the period during which they are weak, because of the lack of food”.
Nevertheless, they do not represent a real danger for humans. Although there are an estimated 3 million jacarans in the Pantanal, attacks on humans are anecdotal, and rarely serious. On the other hand, the threats which weigh on these populations of animals are more and more important. “Deforestation, construction of hydroelectric dams, fires… lists the researcher, have reduced populations in some places to worrying levels”.