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NC3Rs: National Centre for the Replacement Refinement & Reduction of Animals in Research
Project grant

Non-invasive identification of individual Xenopus by photography and image processing

At a glance

Award date
October 2007
Grant amount
Principal investigator
Professor Matthew Guille
University of Portsmouth


  • Refinement



Recent developments in Xenopus transgenic techniques and mutagenesis screens have led to many more strains becoming available and therefore a greater need to identify individual frogs for a variety of reasons. These include improving husbandry information and keeping frogs of multiple genotypes in sufficiently large groups that they feel protected and exhibit normal feeding behaviour. Previous identification techniques (examples included freeze branding, toe clipping, threading tags through the skin and implanting microchips in the dorsal lymph sac) were generally effective but, considering that the animals are normally only used for breeding, probably unacceptable in terms of harm. Our preliminary data suggest that the individuals can be identified using digital imaging and machine vision techniques. We can measure the pattern and hue profile of the backs of the animals and foot veination patterns. Our aims are to develop the identification system, decide whether a single measurement or a combination is needed to identify individual frogs, test whether the markings change over a 2 year period and validate the system at three sites. In the longer term we intend to develop a cost-effective and accurate, commercially available solution to frog identification.