in 2016, devils are at the verge of extinction as the localised populations were shown to have declined by 90 per cent and an overall species decline of more than 80 per cent in less than 20 years, with some models predicting extinction. despite this, devil populations persist in disease-stricken areas. the devils have, in a way, fought back the extinction by developing the gene that is immune to face tumors. the genes have already existed in the tasmanian devil as part of their immune system. they increased in frequency due to natural selection. that is, the individuals with particular forms of these genes (alleles) survived and reproduced disproportionately to those that lacked the specific variants when disease was present.