In 2014, scientific research was published that reported that it had found – among others – endogenous viral elements (EVEs) from a Hepatitis B Virus in the speckled rattlesnake (Crotalus mitchellii). Analysis reveals genome fragments from the virus family were inserted into the genome of this snake over the past 50 million years.
. These elements can be seen as the genetic ‘fossils’ of which can be detected in whole genome sequence data millions of years later. Endogenization of viruses is not rare; in fact, it appears to be a recurrent and on-going process.
Further research for EVEs in the genome of the speckled rattlesnake revealed that there are two fragments with significant similarity to sequences from Hepatitis B Viruses. These were given the names endogenous Snake Hepatitis B Virus 1 and 2 (or eSHBV1 and eSHBV2).
Parrot Hepatitis B Virus.
 Gilbert et al: Endogenous hepadnaviruses, bornaviruses and circoviruses in snakes in Proceedings of The Royal Society – 2014
 Katzourakis et al: Endogenous viral elements in animal genomes in PLoS Genetics – 2010
 Holmes: The Evolution of Endogenous Viral Elements in Cell Host & Microbe – 2011