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Recent Field Research – Reptile and Amphibian Feeding Observations

Eastern Hognos SnakeMany interesting field research reports are published in professional journals such as Copeia, Herpetologica and Herpetological Review, and are not available on the internet.  From time to time I’ll provide summaries of some of the fascinating articles that I come across.  Today’s report, drawn from Autumn, 2010 publications, covers observations of free-living snakes, turtles and caimans.

Giant Meals…even for snakes!

Snakes are “big meal specialists”, but rarely consume animals larger than themselves.  However, a Southern Toad and a Spadefoot Toad, swallowed by different Eastern Hog-nosed Snakes, Heterodon platyrinos, each outweighed the snake by several grams! 

The largest snake meal I’ve personally observed was a 60 pound White-tailed Deer that was consumed by a 16 foot-long Green Anaconda, Eunectes murinus, in Venezuela.  Other notable Anaconda meals include a Red-Footed Tortoise and a Yellow-Spotted Side-Necked Turtle (please see article below for details and other observations).  However, when viewed in terms of predator vs. prey mass, the Hog-nosed Snake meals mentioned above are the largest I know of.

Aquatic Surprises

Northern Watersnake Eating a fishMost semi-aquatic turtles are able to swallow food only while in water, so I was most interested to read of a Chacoan River Turtle, Rhinoclemmys nasuta, that consumed carrion (the body of a Water Opossum) while on land.  The observation was made on Isla Palma, a small island off Columbia, South America.

A Spectacled Caiman, Caiman Crocodylus, in the Everglades National Park was seriously injured when it attempted to swallow a Walking Catfish (neither is native to Florida); both of the fish’s pectoral fins had pierced the Caiman’s esophagus.

Unusual Snake Meals and “Dining Places”

Longspine Sandbur Grass seed heads were found embedded in the mouth of a Prairie Rattlesnake, Crotalus viridis, in Colorado.  The plant is introduced, and its spiny seeds have also been found in the skins of snakes as well.  The seed heads were likely ingested incidentally, along with rodent prey, and would certainly have caused an infection or other problem in time.

A sidewalk at the University of Florida, Gainesville, produced an observation of an Eastern Ratsnake (“Yellow Ratsnake”), Pantherophis alleghaniensis, in the process of killing a Northern Yellow Bat.  A former co-worker of mine once came upon a huge Yellow Ratsnake in the process of constricting a new-born White-tailed Deer (St. Catherine’s Island, Georgia)…I need to re-check my notes for details, and will provide an update when possible.

Most books list typical prey items for various herps, but many species consume an astonishing variety of animals.  I’ve been lucky enough to run across a few surprises – a Black Tree Monitor consuming a House Sparrow, Marine Toads eating salad, and so on; I’ll highlight others in the future. 


Further Reading

Big Snake Meals: my observations and some record-breakers

Video: amazing African Egg-Eating Snake in action

Eastern Hognose Snake image referenced from wikipedia and originally posted by Patrick Coin
Northern Water Snake eating a fish image referenced from wikipedia and originally posted by FotoDawg
Eastern Hognose Snake eating a toad image referenced from wikipedia and originally posted by Dawson


  1. avatar

    Hello Frank,

    You might appreciate this video here. It includes a bit of a phone interview with me, and some clips of footage shot of her eating eggs(a pigeon egg from my hand-and a medium chicken egg in her enclosure)…she gladly feeds in front of people.


    I think of all snakes Dasypeltis can take the largest diameter prey items for their headsize.

    ~Joseph See

    • avatar

      Hello Joseph, Frank Indiviglio here.

      Thanks …great job on the interview and with the egg-eating snakes! I think you’re right concerning head size…simply amazing. Keep up the good work.

      Good luck, enjoy and please keep me posted.

      Best regards, Frank Indiviglio.

About Frank Indiviglio

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Being born with a deep interest in animals might seem unfortunate for a native Bronxite , but my family encouraged my interest and the menagerie that sprung from it. Jobs with pet stores and importers had me caring for a fantastic assortment of reptiles and amphibians. After a detour as a lawyer, I was hired as a Bronx Zoo animal keeper and was soon caring for gharials, goliath frogs, king cobras and everything in-between. Research has taken me in pursuit of anacondas, Orinoco crocodiles and other animals in locales ranging from Venezuela’s llanos to Tortuguero’s beaches. Now, after 20+ years with the Bronx Zoo, I am a consultant for several zoos and museums. I have spent time in Japan, and often exchange ideas with zoologists there. I have written books on salamanders, geckos and other “herps”, discussed reptile-keeping on television and presented papers at conferences. A Master’s Degree in biology has led to teaching opportunities. My work puts me in contact with thousands of hobbyists keeping an array of pets. Without fail, I have learned much from them and hope, dear readers, that you will be generous in sharing your thoughts on this blog and web site. For a complete biography of my experience click here.
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