Herpetologist
JESUS RIVAS
Hardworking Herpetologist
Dr. Jesus Rivas makes a living wrestling some
of the biggest snakes in the world in the llanos
of Venezuela, where some of these huge snakes live. The work involves
long hours enduring the heat of the tropics slogging through the marsh
weeds (riddled with leeches) in bare feet "feeling" for the
unmistakable shape and texture of an anaconda with the sensitive skin
of his feet and toes. Using primitive, but effective tools like cotton
socks and plastic electricians' tape, he captures and restrains them
to gather blood and tissue samples so we can all understand more about
them.
Dr. Rivas has always been fascinated by snakes
and other wildlife, ever since he was a boy growing up in Venezuela.
While other boys were playing superhero he was captivated by the beautiful
and exotic creatures that lived in the wild near his childhood home,
even keeping a 'nature diary' with drawings of the creatures he admired.
As a youngster he had been repeatedly warned by his parents not to touch
snakes and other wild creatures because many of them in that part of
the world are dangerous, even poisonous. He didn't really get an opportunity
to get up close and personal with snakes until he was a teenager and
eagerly volunteered his time at a local zoo.
Part of his responsibilities at the zoo were
to clean the animals'pens and cages as well as feed them, which is
where he got his first opportunity to observe large anacondas killing
and devouring their prey. This early exposure to the captive reptiles
inspired him to want to learn more about the way these creatures lived
in the wild. When he later entered college at the Universidad Central
de Venezuela he chose to study biology.
Dr. Rivas got his first real opportunity to
do field research on the giant green anaconda when a project 'fell
into his lap'. Because of the creative and pioneering work that he
had done studying green iguanas in the field he was the first person
to come to mind when the Wildlife Conservation Society began to round
up some people to conduct a field study of anacondas.
His research would be the
first of its kind ever performed on the green anaconda, as no one had
carried out any field studies of this species before. Very little was
known about the elusive green anaconda and the Wildlife Conservation
Society, together with the Convention for the International Trade of
endangered Species (CITES), and Profauna (the Venezuelan Fish and Wildlife
Service), funded a project to study this species to understand more
about it and try to develop a management plan.
Dr. Rivas and his wife and research partner Renee
carrying a tired snake in to collect data.
During his years of field research on the anaconda, Dr. Rivas and
his research team developed practical and pioneering ways to capture,
subdue and measure some of the biggest
snakes in the world without endangering themselves or harming
the snakes.
Dr. Rivas has since spent 11 years on the
llanos capturing and studying anacondas in the wild to understand
more about them. Here some of the cool things he did learn from his
research so far:
| • |
anacondas
have the largest sexual size dimorphism (difference
in size between the males and the females) of any vertebrate
species (males are 1/5th the size of females!) |
| •
|
when
anacondas mate a large number of much smaller males
will wrap themselves around one large female, forming
a "breeding ball", where the males compete
in very close quarters for the opportunity to mate |
| • |
anacondas
also present a surprising ontogenetic change
in biomass from birth to adulthood, with a 500-fold
increase it is much higher than the increase found in
any other species of snake |
| • |
In
his years of field research on the green anaconda, Dr.
Rivas has captured and 'processed' over 900 anacondas! |
What's it Like to Handle a Huge Green Anaconda?
According to Dr. Rivas,
"It takes an average of about 15-20 minutes of fighting with
a snake before it tires to the point of exhaustion. Then it becomes
easier to handle and more compliant." Because of the large
difference in size between males and females, all of the really
large snakes he has captured are females (the "big girls"
he calls them). Many of the large snakes he has captured weigh
between 80 and 100 lbs. (36-45kgs). Can you imagine trying to
wrestle with 100lbs/45kgs of writhing snake? And then multiply
that over 900 times!
There's still a lot
that is not known about them that can only be learned from long-term
studies conducted by continually tracking and observing them in
their native habitat. Dr. Rivas is currently looking to fund continuing
research of these fascinating and enigmatic creatures by offering
eco-tours of Venezuela and an "Adopt-a-snake"
program. You can read about his research, see lots of great
photos of anacondas, and support his research by visiting
his website at: anacondas.org.
Check it out!!
