Water bulls, also called lake bulls, or huaca mamül, are semi-aquatic, buffalo-like creatures said to inhabit the swamps, lakes, and rivers in Patagonia. This cryptid is notable because there are no native bovids in South America, unlike North America, which has two bison subspecies. They are described as being similar to water buffalo, with thinner, more horse-like back legs, black fur or skin, and a call similar to domestic cattle, but ending with a distinct “aaaah” sound. Sometimes their horns are described as having a distinct yellow or gold hue.
In the western area of the Chubut province, there is a lake named Laguna Del Toro Negro, or “lake of the black bull”, due to a Mapuche legend that in ancient times, before European arrival, a chief killed the water bull that lived in the lake in revenge for killing his son. In 1960, a woman named Sabino Cárdenas saw multiple water bulls appear on the surface of Lake Lolog, before quickly diving back down. She described them as “gigantic cows.” Other people have also reported seeing them in Lake Lolog coming out of the water to graze at night.
A few kilometres south of Lake Lolog, Mrs. Teodora del Carmen claimed she occasionally would see a water bull with gold-coloured horns on the beach near her home off Lake Lacar. In 1995, anthropologist C. Fernandez was told by locals that they avoid a particular creek (at 39°38’ S, 71°17’ W) because water bulls would peek their heads out of the lake, frightening them. Similar reports of strange semi-aquatic bovids have also been recorded nearby at the much larger Lake Huechalafquen.
At an unknown date, a man named Ernesto Bahamondez was visiting Lake Cisnes, which is just east of the Chilean border. Hahamondez noticed an animal he described as a cow with the back portion of its body resembling a “water animal” dive into the lake. The report unfortunately didn’t elaborate on what “water animal” he was referring to.