Lancehead snakes are good at adapting to many different conditions. Therefore, they are often found in close proximity to humans. That is, they have no problems moving into land cleared for agriculture and cities.
This is also the reason why they are responsible for so many snake bite envenomations. According to Venomous Snakes of the World by Mark O'Shea, they account for approximately 90 percent of all venomous snake bites in South America.
The highest density is found in the Amazon region. They are agile animals and not mellow. So this really is a snake you have to careful of when you encounter it.
There are up to 30 lancehead species. In many countries, there are several species that are often confused with one another. They are one the longest of the venomous snakes, as most specimens reach lengths close to 8 feet, which is large. The length, of course, depends on which lancehead snake it is.
Their Latin name is Bothrops, and the different species are called Botrops spp., where the spp is different names. The two most common lanceheads are the Bothrops atrox and Bothrops asper, the asper being the largest of the two.
The photo below is a Botrhops atrox, while the video is a guy being stupid with a highly venomous Fer de Lance in Costa Rica. He is not aware of the danger he subjects himself to when he allows the snake to attack him.
The asper Fer De Lance also goes under the name terciopelo. It is known to be very aggressive, and it is a large and strong-bodied snake..
Although they are not called Fer de Lance snakes or lanceheads, a number of South American species are closely related to the Fer de Lance. Those are called Bothreichis. They are pitvipers and not nearly as dangerous as Fer de Lance snakes, although very close related.
Like most other snakes, their diet is a combination of smaller mammals (rodents), birds, and other reptiles.