Care Sheets


Implanted Microchips



Ever since reptiles and amphibians have been observed and collected in the field, there has been a need for positive identification of individual  specimens. This was originally done by crude methods such as clipping of toes or caudal scales or notching shells of turtles. As reptiles and  amphibians are now present in zoos and private collections in ever  increasing numbers, a need has arisen for permanent, positive identification of individual specimens. The following article will  discuss the use of Avid transponders, small identification chips that are injected into specimens for permanent identification. The chip is  read by means of a scanning gun which provides a ten-character  alpha-numeric readout of the chip implanted in the animal. Specific use of this identification system in three large private collections and one zoo will be discussed.

Why Identify Animals

There  are a number of reasons for positive identification of individual animals. The first most obvious reason is for theft deterrence. Animals  in both private collections and zoos have increased dramatically in  value over the past few years, and thefts of valuable specimens have  been seen in both places. Use of the Avid transponders would not only  decrease the likelihood of theft, but also increase the chances of  recovery of the specimen. Positive identification of animals would also  help resolve insurance claims and may decrease premium costs.

The second reason for use of the transponder is for inventory control. The Avid system has now been internationally recognized as the identification system of choice for animal collections. Zoos throughout the world are incorporating Avid ID systems into their animal databases  such as ISIS. At their recent meeting in Japan, the Convention on International Trade in Endangered Species (CITES) named the Avid system  for use when specimens are shipped internationally.

Another  reason is for positive identification within a collection. Animals are  now being bred in captivity in record numbers. Some animals such as the brown water python (Liasis fuscus) are unicolored and patternless, making it very difficult to visually identify individual  specimens when housed as a group. The Avid system will permit this  identification without physically disturbing the animal. The same can be true for the field herpetologist, especially when a large number of animals must be individually identified.

The Avid system would  be particularly attractive to breeders working with legal, protected  animals. As a particular example, the private reptile breeders in Florida are quite anxious to work with their native species, especially  the eastern indigo snake, Drymarchon c. couperi. To date there have been strong reservations by the state wildlife management people that,  especially with the indigo, there is no way to distinguish a legal, captive-produced specimen from a wild-caught individual. This identification system may go a long way in resolving the issue.  Captive-bred specimens could be registered with the Florida Game and  Fresh Water Fish Commission, along with the implanted identification  number. As the transponder is virtually impossible to falsify, it would  be relatively easy to verify the origin of animals in collections.

The system also permits identification safely, with minimal stress to  the animal. As the identification is passive, the implanted chips can be read from a distance of about a foot.

Finally, as the  captive-breeding industry is rapidly expanding, it is advantageous from both the buyer and seller's points of view to have animals positively identified. This is especially true when a significant amount of money is paid for animals heterozygous for albinism. If the animals should prove to be normal rather than heterozygous, a positive identification system would be essential for the settlement of potential disputes.

The Avid System

The transponder consists of a wire-wound glass-encapsulated chip, about the size of two grains of rice laid end-to-end. These chips come from the supplier pre-loaded into a 8-10 gauge  hypodermic needle. Using an insertion tool very similar in appearance to a syringe, the chip is injected either subcutaneously or  interperitoneally into the animal. Location of injection site varies  with type of animal. Barker and Barker (pers comm., 1990) performed a  comparative anatomy study of various species of pythons and concluded that the area approximately twenty ventral scales before the anal plate  poses least risk of interference with vital organs. For the study, we chose that site and injected the chip subcutaneously at the junction of  the ventral and lateral scales. For their large snakes, the Columbus Zoo has chosen the dorsal muscle mass in the same location on the body. Turtles have also been injected intraperitoneally, with the injection site just anterior to a hindlimb. To date, over 1,000 reptiles have been implanted at three private collections, without a single injury noted.

The Avid transponders themselves are inexpensive. The cost is  approximately $10.00 per chip, pre-loaded in its needle in a sterile  individual package. Thus, it would cost approximately $30.00 for a veterinarian to implant an individual animal. Implantation of a number of animals at a time should decrease this cost.

The chips are  then read with a device about the size of two decks of playing cards. The reader is pointed at the individual specimen and, as the tag is  read, a ten character alpha-numeric code is displayed on the gun. In this configuration, over a billion combinations are possible, virtually  eliminating the possibility of duplication or falsification. This  reading is done in a totally passive mode, providing no danger or discomfort to the animal.

The reader gun is relatively expensive, retailing at approximately $350, but purchase of the gun is not  necessary to attain the benefits of this system, as many zoos, veterinarians, shelters and wildlife management organizations already  have them. Since they would not be in constant use except in very large  collections, it may be worthwhile for regional herpetological societies or groups of private collectors to pool resources to purchase one


The Avid transponders have been  evaluated in both private and zoo reptile collections and found to be a safe and reliable means to permanently identify animals. Potential benefits of this system are theft deterrence, pedigree assessment and  verification of legal protected animals. It is strongly recommended for  zoo collections, and its low cost makes it within reach of the serious  hobbyist.

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