Dates: Middle of May through July (approx. May 15th-July
20th 2014)
Job description: The Clark lab at San Diego State University
is seeking motivated individuals to assist in a behavioral study on predator-prey
interactions between northern Pacific rattlesnakes (Crotalus oreganus oreganus) and California ground squirrels (Otosperomphilus beecheyi). Individuals will live and work with other
field assistants at the Blue Oak Ranch Reserve in the foothills east of San
Jose, California. Assistants will help
with capture and radio telemetry of rattlesnakes, implementation of fixed
videography in the field, and behavioral experiments on wild animals. This a
great opportunity to gain experience with trapping, marking and handling of
animals, radio telemetry, GPS, videography, and other basic behavior and
ecology field techniques.
Qualifications: No experience necessary, but applicants with
lab or field research experience will be given priority. On-the-job training
will be provided. Must be able to hike
long distances over rough terrain carrying heavy equipment, conduct patient
observations for long periods of time (up to 10 hours/day), and live in a
remote wilderness area with primitive facilities. Must be able to work and live
comfortably in variable environmental conditions including both cold/hot
weather and in tick/mosquito habitats. Must be passionate about science, hardworking,
independent, good-natured, love working in the outdoors, and able to share
close living quarters with other researchers. Room and board (research facility
fees and food) are provided, but interns will be required to sleep in tents for
the entirety of the field season.
Application: Please apply by April 15th. To apply, please send a cover letter and
resume (including contact information for three references) detailing your
experience with field biology, outdoor skills, and animal behavior to Bree
Putman at: breeput@yahoo.com
The way you eat probably doesn't change
much daily. Sure, you have to make a few decisions like whether you should go
out, get delivery, or make food at home. You also must decide whether to eat
with your hands or silverware, at the dining room table or on the go. But
overall, your mode of eating generally consists of preparing a meal which you take
approximately 10 minutes to consume while sitting down, and as with most things
in life, there are exceptions to this rule (like Adam Richman of Man Vs. Food).
This man is an exception to the "human foraging mode"
Unlike humans, snakes have two main
foraging modes called ACTIVE and AMBUSH (or sit-and-wait). Active foraging consists
of actively searching for and pursuing relatively immobile prey (e.g. sleeping
or resting prey, or prey such as newborn animals). Ambush foraging consists of
remaining at a hunting site for several hours to days to opportunistically
attack prey that passes by. Active foragers generally have high endurance, but also
high energy demands, while ambush foragers are low energy specialists, but have
low endurance.
Characteristics of the two main foraging modes in snakes
Browsing is also recognized as an
alternative hunting mode in some snakes. For instance, Turtle-Headed Sea Snakes
(Emydocephalus annulatus) in New
Caledonia swim slowly searching for fish nest eggs in crevices along the ocean
bottom (Shine et al 2004). A fourth foraging mode in snakes is less understood:
SCAVENGING! Many people have described scavenging in snakes, but few have
conducted formal studies on this interesting behavior (I could only find one during
a quick literature search). Snakes are thought to employ scavenging
opportunistically, eating carrion (dead decaying animals) only when chance
allows. The one study I found showed that Western Diamondbacks (Crotalus atrox) were willing to consume mice
that had been dead for 48 hours, but Black Rat Snakes (Elaphe obsolete) were not. The Diamondback rattlesnakes could even
locate dead mice hidden within gravel (probably using their sense of smell).
(http://www.tigerscursebook.com/blog/post-203/)
A review in 2002 by Devault and Krochmal
found 39 published accounts of scavenging in snakes, which in total yielded 50
observations of this behavior. I’m sure that more than 10 years later, this
number has increased. They found that pit vipers (snakes in the family
Crotalinae) and piscivoruous snakes (those that eat fish) were most commonly reported
as scavenging. Scavenging was also not limited to one prey type. What still remains
unclear is what percentage of snakes’ total diet consists of scavenged carrion.
This question is nearly impossible to answer with traditional snake diet
studies that examine gut contents. As you can imagine, it is extremely hard to
determine whether digested material in the gut came from freshly killed prey or
carrion. One would need to literally observe a snake’s foraging behaviors 24/7
to answer this question.
The research we conduct in the Clark Lab
attempts to expand our knowledge on rattlesnake (Crotalus oreganus) foraging behavior and diet with the use of fixed videography. Cameras overlooking snakes record their behaviors for prolonged
periods of time, sometimes capturing rarely observed events. I am pleased to
announce that this past summer (2013), we finally found a scavenging rattlesnake!
Ironically, we did not discover this snake with our fixed video cameras, but by
chance. Watch Iggy scavenging on my YouTube channel!
We found Iggy, a pregnant female
northern Pacific rattlesnake on May 23rd at 11:46 am. She was
scavenging a decapitated ground squirrel pup lying on the edge of a dirt road.
She attempted to eat it several times over 7 minutes. She also dragged its body
16 meters from its initial location. Iggy had a hard time consuming the dead pup
probably because it was missing its head, and snakes mostly consume their prey
head-first. From our video recordings of her attempting to consume the pup, it
seems that she was able to locate the anterior (front) region of the body, but
could not get a good enough grip to start the consumption process. Eventually
she gave up on it and slithered into the shade of a burrow.
References:
Devault TL, Krochmal AR (2002) Scavenging by snakes: an examination of the literature. Herpetologica 58:429–436.
Gillingham C, Baker E (1981) Evidence for Scavenging Behavior in the Western Diamondback Rattlesnake (Crotalus atrox). Zeitschrift fuer Tierpsychologie 55:217–227.
Lillywhite HB, Sheehy CM, Zaidan F (2008) Pitviper Scavenging at the Intertidal Zone: An Evolutionary Scenario for Invasion of the Sea. Bioscience 58:947–955.
Shine R, Bonnet X, Elphick MJ, Barrott EG (2004) A novel foraging mode in snakes: browsing by the sea snake Emydocephalus annulatus (Serpentes, Hydrophiidae). Funct Ecol 18:16–24.
