Ultimate Explorer Snake Hunter Stalks Constrictors

Brian Handwerk
for National Geographic Ultimate Explorer
August 1, 2003

More National Geographic News stories about Snakes>>

For the past 11 years, National Geographic Ultimate Explorer guest correspondent Jesús Rivas has studied constrictors. This reptile family includes such notable snakes as anacondas, pythons, and boa constrictors, all big animals notorious for their ability to tackle prey even larger than themselves.

In Ultimate Snake Rivas, of the Universidad Central de Venezuela, journeys around the globe to seek out fascinating constrictors and the scientists studying them.

In Puerto Rico, boas have taken to the trees where they lurk near the mouths of caves. There, night-vision cameras capture them preying upon the many bats who emerge each evening—hunting them effectively even in pitch darkness.

Australia's woma pythons hunt underground in tunnels away from the searing heat of the surface. There the hardy reptiles employ an adaptive technique—using their bodies to crush their prey against the walls of the narrow tunnel.

And in South Africa, Graham Alexande of the University of the Witwatersrand has made discoveries about southern African python parenting. His findings challenge the commonly held belief that newborn pythons are left to fend for themselves, and show python mothers in a more nurturing light.

At home in Venezuela, Rivas continues his ongoing research on the green anaconda. During a unique long-term study funded in part by the National Geographic Society's Committee for Research and Exploration, he's become the world's foremost expert on these little-known but fascinating giants.

Anaconda Research a 'Hands-On' Proposition

Rivas' work is hands-on in the most literal sense. To study these reclusive animals, he wades barefoot through the swamps of Venezuela's llanos wetlands ecosystem in search of his water-dwelling subjects. Once found, he wrestles them into exhaustion with his bare hands.

The dangerous work is necessary, because the snakes don't lend themselves to other kinds of study. "With snakes in general, they are so secretive that if you get to see them long enough to catch them you're lucky, let alone long enough to do naturalistic observations," Rivas explained. "Some animals can be studied with hands-off observation but these snakes are hard to deal with in that sense."

Despite the challenges, Rivas and his team have captured and released more than 900 animals over the past 11 years, including some 170 recaptures. They've also studied the breeding cycle of 47 females, providing an unprecedented look at these "ultimate snakes."

Green anacondas are reported to be the largest snakes in the world. They reach lengths of nearly 30 feet (9 meters), can weigh 1,200 pounds (550 kilograms), and some tales tell of even bigger snakes.

Continued on Next Page >>


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