Wet Preserved Reptiles and Amphibians - By: Richard E. Etheridge(1996). Modified/Updated By: The owner of this blog

Before reading: I do not recommend using alcohol as a preservative, from my research and from what I have been told by many professionals is that formalin is the only way to go. Please see the MSDS for 10% formalin and take all of the required precautions prior to even attempting preservation with formalin. Please note that this was written in 1996 and is not completely up to date; I have modified what he has written for this reason. If you would like to read the original document please see: http://www.lsa.umich.edu/ummz/herps/collections/herp-prep.asp

PLEASE NOTE: Do not remove any animal from the wild or pick up anything dead that you find with out checking with your area/states/government Department of Fish&Wildlife to see if it's legal to have in your possession. Any animal that is endangered or protected under the law is illegal to pick up and you should not touch it without risking getting a large fine.

Information written by: Richard E. Etheridge (adapted for the WWW and updated by M. O'Brien and G. Schneider, May 1996)

Most of the larger museums and universities that maintain preserved collections of reptiles and amphibians have curators trained in the approved methods of preparing and maintaining an alcoholic collection. On the other hand, many individuals with a non-professional interest in natural history have the inclination and opportunity to obtain and preserve herpetological specimens but lack knowledge of the proper techniques. It is the purpose of this article to be of help to these persons, for even small collections casually assembled may be of great usefulness if the specimens are adequately labeled, well preserved, and fixed in a standard position.

Steps for the preservation of specimens for sclentific study are as follows:

1. Injection and slitting. Liquid preservatives must be introduced into the body cavity, limbs and tail, either by hypodermic injection or through slits.
2. Fixing. While the specimens are still relaxed, they should be arranged in trays so that they will harden in the proper position.
3. Labeling. Each specimen should be accompanied by certain data, either attached directly or entered in a notebook with a number corresponding to a numbered tag tied to the specimen.
4. Storage. After specimens have been fixed in the proper position, they should be stored in liquid preservative for at least several days, after which they may be allowed to remain in the liquid, or transferred to plastic bags for temporary storage.

Preserving Solutions

Formalin: If at all possible, formalin should be used for injecting and fixing specimens. Formalin is the commercial name of a solution of formaldehyde gas (CH20) in water. This is sold only online. In Latin American countries, formalin may be purchased in many drugstores under the name "Formol" or "Formolina". Formalin must be diluted with water before it is used as a preservative. A strength of 10% formalin is best for most purposes. If the original strength is 40%, it should be mixed at a ratio af nine parts water to one part formalin. Issues with using formalin over other preservatives are: it is a carcinogen, it is not easily obtained, there are many precautions you have to take, it can be expensive. The positive to using formalin is that specimens almost never decay in it. Its other principal disadvantages are: it has a very irritating odor, it is very poisonous and may cause skin irritation or rash, it has a tendency to make specimens become brittle if the solution is too strong(depending on the type of animal), and tends to fade out certain colors rapidly, and it must be stored in rustproof containers. (Buffering of the 10% solution is recommended as formalin is slightly acidic. One buffering system that may be used is a mixture of monobasic and dibasic Sodium Phosphate, at 13 gm/gallon [Monobasic] and 24 gm/gallon [Dibasic]).

Alcohol: I DO NOT RECOMMEND THIS FORM OF "PRESERVATION" WHAT SO EVER. This "preservative" is easily attainable, but not recommended by myself(owner/writer of blog). For injection and fixing it should be used at full strength you need to use 95% or higher. For storage of reptiles it should be used in the proportion of 3 parts 95% alcohol to 1 part water. Alcohol which has been stored in open containers loses its strength rapidly due to evaporation. Strength may be tested with an alcoholometer. Specimens which have been fixed in alcohol should be carefully watched for signs of rotting(this is because alcohol is not a good preservative, it may preserve the skin but its innards are definitely going to rot). 

Preparation: If specimens are to be made permanently immune to decomposition, it is necessary that liquid preservative be introduced into the body cavity, limbs and tail within as short a time as possible after the animals have been killed. This may be accomplished either by injection (with a hypodermic syringe) or by making deep cuts with a sharp scalpel, razor blade or scissors(I personally recommend using a syringe). The most satisfactory way is by injection. A ten or twenty cc. syringe with a needle lock and several needles (guages 18 to 26) will serve to inject most specimens.

Frogs and Toads: Injection should be made through the belly, directly into the body cavity. If the body is puffed with air, it should be deflated by gently squeezing with the fingers. Very small frogs require only a few drops of preservative; frogs two or three inches long only a few cc. Introduce only enough preservative required to make the specimen look natural--it should not look bloated. It is not necessary to inject the legs of any but the largest frogs. If equipment for injection is not available, a single slit may be made in the abdomen, to one side of the midline. The slit should be deep enough to allow free access of the preservative into the body cavity.

Salamanders: Most salamanders do not require injection or slitting. If your specimens look "caved in" a small amount of preservative may be injected into the body cavity, or a single slit made in the abdomen to permit preservative.

Tadpoles: Tadpoles and small salamander larvae should always be preserved in 10% formalin, never in alcohol. Simply drop the tadpoles into formalin while they are still alive. Be sure there is enough preservative to cover them and avoid overcrowding. After 24 hours all the liquid should be drained off and replaced with fresh formalin.

Lizards: Injection should be made through the belly directly into the body cavity. Care should be taken not to use too much, or the body will become unnaturally distended. A series of slits should be made in the under side of the tail with a sharp scalpel or razor blade. The slits should be from 1/8 to 1/4 inch long and about 1/4 inch apart, and should extend from the base of the tail to the tip. Very large lizards must be injected or slit in the thicker portions of the limbs and neck. If space does not permit preservation of very large lizards whole, they may be skinned out, except for the head. To skin a large lizard, make a cut down the belly from the neck to the base of the tail. Work the skin loose from the body, pulling the skin of the arms and legs inside out as far as the wrists and ankles. Do not attempt to skin out the head, hands, feet or tail. Sever the wrists, ankles, neck and base of the tail, and remove the carcass. The skin should then he placed directly into preservative. If possible, one hemipenis of male lizards should be everted. This can be accomplished hy injecting preservative into the base of the tail (before slitting) and at the same time applying pressure with the thumb just behind the anus (Fig. 1 A).

Snakes: Make a series of injections an inch or two apart(sometimes 3") through the belly into the body cavity. Begin just behind the head and continue the injections to the anus. If a syringe is not available, a series of slits must be made in the belly. For most snakes the slits should be about an inch apart and an inch long; smaller slits closer together for very small snakes. Just as in lizards, a series of slits must be made in the under side of the tail and one hemipenis everted in males (Fig. 1B). Very large snakes may be skinned out, leaving the head and tail attached. To skin a snake make a single, long cut in the belly, just to one side of the midline, beginning about an inch behind the head and continuing to about an inch in front of the anus. Do not cut through the anal plate. Work the skin loose from the body, but do not attempt to remove the skin from the head or tail. Sever the body an inch behind the head and an inch in front of the anus, and (after recording the stomach contents, number of eggs, embryos, etc.) discard the carcass. Put a strip of cloth on the inner side of the skin and roll it up, beginning at the head. Tie the roll with a piece of string and put it directly into preservative.

Alligators and Crocodiles: Small individuals may be preserved just as lizards. Larger individuals should be skinned out with the head attached, rolled up and placed directly into preservative.

Turtles: Preservative should be injected into the body cavity just in front of each of the four limbs, between the carapace and plastron. Use a long needle and continue injections until the head and · limbs are forced out of the shell. If a syringe is not available, make deep cuts into the body cavity just in front of each leg. Limbs, neck and tail should be injected or slit, as in large lizards.

Below are some old practices and are not required, you can pose your animal however you want. It is required that you check if the animal you want to preserve is legal. 

Specimens should be injected (or slit) and tagged as soon as possible after they are dead and fixing should immediately follow. If you are unable to preserve at this time, store your animal in a plastic bag or plastic container and in your freezer(this helps keep your specimen from decaying prior to preservation). Individuals may be placed close together on the tray but should not touch each other. The tray should be covered to prevent evaporation. Most amphibians will harden in a few hours, reptiles in 10 or 12 hours. Large lizards, frogs and turtles may take a little longer.

Snakes: Small snakes may be coiled flat in the tray if the coil does not exceed three and one half inches in its outside diameter. The head should be inside as in Fig. 2 C. Larger snakes should be coiled in a jar and covered with preservative. If the snake has been injected it may be coiled with the belly down, tail at the bottom and head on top as in Fig. 2D. If slits are used, it should be coiled with the belly up, head on the bottom and tail on top. Tall, narrow bottles should be avoided; quart and pint sizes are best. Snakes too large to coil in a gallon jar should be skinned.

Lizards: Place the lizard belly down, with arms, legs and tail extended. If the tail is very long it may be bent around the side of the body (Fig. 3 A). Attenuate, limbless lizards may be coiled like snakes.

Turtles: Most important in fixing turtles is that the head and neck be extended and the mouth propped open with a bit of wood or cork. The limbs should also be extended if possible.

Salamanders: Belly down, arms, legs and tail extended as in Fig. 3 B. A salamander tail will often twitch back and forth long after the animal seems to be dead. Ten or fifteen minutes after they have been laid out check to be sure the tail is still straight. Large specimens, 10 or more inches in length, may be coiled like snakes.

Frogs and Toads: Place the frog belly down, arms and legs extended as in Fig. 4 A. The fingers and toes should be separated and extended, especially if they are webbed. The inner margin of the forelimb from the elbow to the tip of the fourth finger should form a straight line. The sole of the foot may be up or down, whichever seems most natural (down in treefrogs and up in most other frogs and toads).

I do recommend the following

Storage: After the specimens have been injected or slit, tagged(not required unless your fish and wildlife department directs you to do so), and fixed, they should be put directly into preservative. If they are to be transferred later to plastic bags for temporary storage or to be shipped they should first be allowed to remain completely immersed in preservative for at least 48 hours if formalin is used, or a week if alcohol is used. The longer they are allowed to stay in preservative, the better. They should be loose and completely covered with plenty of liquid. Specimens which have been hardened in trays should also be allowed to soak in preservative for a day or two before being shipped or placed in plastic bags for storage. If space is no problem, preserved specimens are best kept in glass containers. Bail-top jars with a glass top and rubber gasket are best. Fruit jars with a metal screwtop lid may be used but should be carefully watched for rust and evaporation. Glass jars with polyethylene lids and liners are more commonly used in collections, since the lids form a tight seal and are easier to obtain than the traditional bail-top jars. Metal containers should be used only for temporary storage unless coated on the inside with paraffin, "Bakvar", or some other rustproof material.

Specimens should be loosely packed and completely covered with liquid. Containers must be periodically checked for evaporation and refilled if necessary. At the first sign of decomposition the affected specimen should be removed and thrown away, or deep cuts made into the body cavity and placed alone in a large container with plenty of fresh preservative. A green spot on the abdomen of a snake or lizard indicates a rotten gall bladder which should be cut out. Any specimen that floats in the preservative contains air or other gases and is not properly preserved. It should be squeezed or slit to permit the gases to escape and the preservative to enter.

When in your personal possession: 
Most people recommend storing your specimens in 70% isopropyl alcohol because it's cheap and readily available. There are other holding liquids but it all varies on personal opinion and what you find works best for you.