Corn Snake Research
formally known as Elaphe guttata
Some books and websites will refer to the corn snake as Elaphe guttata. After extensive research by groups of scientists and herpetologists, the genus and species (binomial nomenclature) of the corn snake was renamed in mid 2004, changing the snake’s name from Elaphe guttata to Pantherophis guttatus. This change was necessary because scientists found the corn snake more closely related to the genus Pantherophis than Elaphe. The full article describing this change was published in the July 2004 issue of Reptiles Magazine.
Corn snakes are from the family Colubridae, which are nonvenomous snakes and pose no threat to humans. The snakes in this family are constrictors, which means they kill their prey by constriction rather than injecting their prey with venom. Constriction takes place through a series of muscular contractions in which the snake suffocates the prey by not allowing the lungs to expand. With every breath the prey breaths out the snake squeezes just a little bit tighter until the prey’s lungs can no longer expand causing its death.
Snow and Amelanistic Wild Type
Females are normally ready to breed approximately one to two months after coming out of brumination, and lay their clutch in or around the month of July. Females will eat whenever the opportunity arises building up their fat reserves, whereas males eat occasionally keeping their main focus or agenda on finding a female in whom to pass on his genetic information. After insemination, the female lays anywhere from 8-20 eggs, depending on the size of the female, in approximately 30 to 35 days. The eggs should be kept in the incubator and hatching occurs 80-90 days later. Incubator should be kept in a constant 80° - 85° F (25°- 29° C) temperature range. If temperatures fluctuate too much it may take longer for the eggs to hatch, some in excess of three months. Some reptiles, including snakes, are known to store sperm. If this occurs, the snake will lay another clutch in or around August-September, or possibly a third in or around October.
Snakes intertwine during mating process, aligning their cloacas
Anerytheristic hatchling '04
Corn Snake Mating Pair
Amel (M) X Snow (F)
Eggs from clutch were laid sooner than expected. The normal gestation period is 3 to 4 weeks (21- 28 days). They were found Monday morning in the corner of the tank when I inspected the cages first thing in the morning. I quickly retrieved the 11 eggs and put them into damp vermiculite in the incubator to see if any will hatch. They looked pretty dehydrated. I now know that the female is able to pass a clutch without getting bound. Good sign. I decided to try to breed her again and try the process one more time.
Amel (M) X Snow (F)
Interesting pattern to eggs above. Looks as if they are dehydrated a bit.
I chose to not disturb the placement of the eggs in the container since they were in that particular orientation for several days prior to being placed in the incubator.
First signs of hatching approximately 11:00 AM July 12, 2008
At 8:30 PM there were only 2 snake eggs that began hatching so far, the Amel in the foreground and the one egg in the background with bubbles. The snake in the background looks as if it will be a "snow" like the mother.
Late night photography. Trying to get the "great" shot!
Day 2: Sunday 7/13/08 9:00AM
The Amel fully hatched and the Snow is poking its head out. The video clip below shows how the Amel moves around the eggs as if it's inspecting and helping the others through the process.
Phenotypes: 4 Snow, 6 Amelanistic, all with albino eyes
Undeveloped Corn Snake Egg
In the photos above, this egg was the one on the bottom right of the screen just under the top right amel.
This egg was hard (it was stiff) and not pliable like the other eggs. Since it was day 3 of hatching and all the other eggs showed signs of activity (heads popping out) I decided to open the egg and see why is was different than the others. I found that the egg was unformed and still in the early stages of development. Once the egg was opened, it confirmed my conclusions that this particular egg was not going to hatch as its hatchlings. It did not smell stagnant. Since this egg was on the bottom of the pile, it was most likely one of the first eggs laid. Since the snow laid previous clutches that were not viable and this was the first clutch laid which produced viable eggs, it may be possible this was a remnant of the prior insemination. Or, it could just be an egg that was an outlier and did not develop as the others did.
Three days have passed since the last egg hatched and I've noticed there are 2 more eggs (below: right top and bottom eggs) that did not form as the egg in the photo above. There is one last egg that has not hatched that seems viable (below: bottom left egg), however, it has a tiny bit of tissue protruding from the shell. I will continue to watch the egg.
Three snakes were purchased at the Orlando Expo for educational research purposes
Reptiles go through a process called brumination (like hibernation) in the cold months, usually in December – February. It is common for snakes in the wild to find a cave or hollow tree stump to “sleep” for a period of time. This is called the cooling down period and normally takes place just prior to mating in the spring. Captive snake’s tanks should be allowed to cool down, removing any heat pad source and allowing temperatures to fall as low as 50° F. Snakes in captivity during the brumination period may just seem inactive and refuse to eat. Brumination is a normal occurrence in nature; so do not be alarmed if a corn snake does not eat during this time period. During the month of March snakes become more active and seek out mates. Females will eat whenever the opportunity arises building up their fat reserves, whereas males eat occasionally keeping their main focus or agenda on finding a female in whom to pass on his genetic information. Females normally breed approximately one to two months after coming out of brumination, and lay their clutch in or around the month of July. Some reptiles are known to store sperm. If this occurs, the snake will lay another clutch in or around August-September, or possibly a third in or around October. Snakes will then eat large meals in late December preparing for the next brumination period. Captive snakes are know to live as long as 20+ years, with wild snakes having a much reduced life span due to natural predators, including road kill and frightful humans.
Corn snakes normally eat once a week to once every other week. Size of the meal varies depending on the size of the snake. Mouse size range in order from smallest to largest: pinkie, fuzzy, hopper, small mouse, medium mouse, and large mouse. Hatchlings in captivity eat pinkie mice (tiny baby mice without hair). They are affectionately called pinkies due to their pink appearance. Juvenile snakes move up to fuzzies and hoppers, then to small, medium, or large mice. Larger snakes may eat small, medium or large rats. Rats are larger in size from birth and may also be referred to as pinkies, small- large rats much like the naming of mice.
Corn snakes are commonly found in the Southern United States, particularly Florida, with some populations reaching as far west as Louisiana and as far north as New Jersey. These snakes are nocturnal, meaning they sleep a good portion of the day and become very active at night. In the wild corn snakes are found in underlying brush, leaf litter, old tree stumps, under rocks or logs. They are also great climbers and can slither up a tree, or desk, in no time at all.
In captivity corn snakes need a large enough tank (to accommodate growth) with a secure locking lid, substrate (bedding) in which they can burrow under, a piece of cork or similar substance to hide in or under, and a water dish large enough for the snake to immerse itself in (one that cannot be tipped over). Fresh water is very important to corn snake health. Snakes will bathe in the water dish and also use it as the restroom, so make sure the dish is clean and filled at all times. Hatchling snakes can be kept in a small 10-gallon tank with locking lid. Larger snakes move up to 20-gallon tanks, and so on, to accommodate the snake’s movement and growth. Snakes spend a great deal of time curled up in a ball underneath their hiding spot while some prefer to stretch out under the substrate. In either case, snake keepers need to be prepared to make the switch to a larger enclosure when the snake increases in size. Also keep in mind that snakes become very active at night. They will explore their habitat and go on the hunt each evening. Captive snakes will search for openings in the enclosure, pushing on the screen lid with their mouth. This is the main reason for having a secure lid that snaps shut or locks. Remember they have an excellent memory and will escape from any opening time after time (assuming the snake has been found the first time).
Snakes normally shed every month. A telltale sign of a snake prior to shedding is when the snake’s eyes look opaque or milky. This means the snake is getting ready to shed within a week, give or take a few days. This is the result of a normal growth process and occurs more frequently if the snake is fed more often than what is considered normal (a term known as “pushing”). If the snake’s environment is too dry the snake may have difficulty shedding and skin will come off in pieces rather than one continuous shed. If this occurs try misting the snake with a spray bottle just prior to the next shedding when the opaque eyes are noticed.
When health issues arise, it is highly recommended that the snake owner find a reputable veterinarian that deals with reptiles (exotics). Corn snakes are very easy to take care of, but occasionally snakes will come in contact with parasites, viruses, or acquire respiratory infections, especially if they are housed with other snakes in the same tank. It’s always a good idea to keep new snakes in a tank by themselves for several months before introducing another cage mate. This will help insure that the snake is healthy and adjusting to its surroundings and also alleviates unnecessary stress to the snake.
Corn snakes do have teeth and will bite in self-defense if they feel threatened, however, their first response is to flee or slither away. These snakes are normally very docile and are great snakes for any beginning herpetology enthusiast. Don’t show fear. Pick up the snake from above, scooping hand under the ventral side (underside) of the snake. Do not squeeze the snake, as this will frighten it, but rather allow the snake to move freely through the handler’s fingers. The more a snake is handled the more familiar it becomes to life in captivity and the less likely the snake will be prone to striking at the handler’s hand.
Always wash hands with soap and warm water after handling any reptile to eliminate possible contamination of reptilian salmonella. As a note of caution, never kiss a reptile.
For further information regarding using reptiles in public education refer to the website http://www.anapsid.org/repsineduc.html
Decomposition in Progress
This is the snake Tyler and Rene' brought into class. This snake had been fatally injured by an automobile. So far, this decomposition process has taken 12 weeks. The flesh eating bugs, Dermestes maculatus, are slowly eating the carcass, removing all the flesh from the skeleton. When this process is complete we will have a preserved specimen to observe in class.
The finished product/ July 2003
Generalized Arrangement (Male)
In a female snake, the testes are replaced by ovaries positioned in the same area of the body.
Lab Photos Coming Soon
Corn Snake Genetics
Mendelism Through Corn Snake Genetics
by Kristin King
Article published in National Science Teacher's Association (NSTA) Journal,
"The Science Teacher" January 2004
Pdf link posted with permission from Jennifer Henderson,
Managing Editor of "The Science Teacher", 1840 Wilson Blvd., Arlington, VA 22201-3000
and Liz Delaney, Internet Editor, NSTA Publications
Feedback from Teachers & Faculty
I receive many emails about the corn snake genetics lab. I will begin to list some of them here. Thank you for your encouragement!
Date: 30 Apr 2005
I have read your article in the science teacher when you first published it and have done the corn snake genetics activity with my biology classes. It was a wonderful activity and both the students and I enjoyed it. It also led me to extend my own reptile collection to include 3 corn snakes. This spring my students got to observe two of the snakes' mating rituals and last week watched as the female laid 15 eggs (she did that during class and my students got to watch the whole thing). We have put the eggs in the incubator and hope for a good hatching rate. I want to thank you for getting us inspired for this whole activity, which has taken on a life of its own. Also, if you have any tips on incubation and hatching, we are definitely on a learning curve here.
Thanks again, Christine Roland
Sunday, September 04, 2005 5:37 AM
Subject: Re: Corn Snake Genetics Lab
Congratulations ... excellent news!!! I have used the article that you published in The Science Teacher 2-3 times now in my science methods class as an example of the material that science teachers can access in terms of professional development ideas ... *very* well received.
Do let me know how you are doing, and do keep in touch.
Dr. Aldrin E. Sweeney
Associate Professor, Science Education
Undergraduate/Graduate Program Coordinator & Program Advisor
Department of Teaching & Learning Principles
College of Education (123 L)
University of Central Florida
Sent: Thursday, July 05, 2007 8:44 AM
I just visited your website on the use of corn snakes to teach genetics. As a teacher, an avid snake lover and the owner of several corn snakes, I was intrigued! I noticed the dates of the emails on your site were 2005. Is your material still available for purchase?
4/15/09Kristin My wife Beth and I spent most of this morning on your web site. It is outstanding. The material offered is very interesting and the presentation really engages the visitor. We were certainly engaged. I especially enjoyed the BIO Newsletter and the parent survey, which I started to complete and decided it should really be completed by parents of students attending Eau Gallie High School. Beth was really into the Bearded Dragon Rearch and the Corn Snake Research. Beth, being a retired Art Teacher, also enjoyed the color wheel within your Solor System page. Kristin, the web site is very well done. Knowing something about web sites, I also understand and appreciate the amount of time and effort that you have invested in this great teaching and learning tool. Beth and I thank you for the wonderful experience of visiting your web site. Have a great week. Dr. Doherty University of Central Florida