Scientists have discovered why cockroaches love filthy conditions and what makes them so hard to kill — and apparently, it's all in their DNA.
Researchers say they have identified specific genes which allow the critters to do anything from eating toxic food to regrowing limbs.
Shuai Zhan, of the Institute of Plant Physiology and Ecology in Shanghai, says the American cockroach has one of the largest genomes known to exist among insects.
The omnivorous scavenger is ones of the largest insect species to live in such close proximity to humans, but also has the exact same number of genes as us — that's 20,000 in all.
After studying their DNA, Zhan discovered cockroaches have genes which allow them to sense smells from food, especially fermented food.
They also have genes to combat infections, which makes roaches resilient to dirty living conditions and others allowing them to grow back broken limbs.
Scientists last year discovered that female cockroaches don't need a male partner as they can reproduce for years without mating.