Scientists find 30% of catfish population in Vermont lake affected by a transmissible cancer

Tasmanian devils, dogs and shellfish are some of the only animals that are known to carry naturally occurring cancers that can pass between individuals. But scientists in Vermont have discovered a new animal species that can do the same, catfish. When they researched the mysterious black skin lesions afflicting catfish in Lake Memphremagog and other New England and Canadian lakes, they discovered a skin cancer that is spreading from catfish to catfish, making it the fourth transmissible cancer ever found in nature.Tasmanian devils bite each other's faces when mating or fighting and thus let tumour cells pass directly from one animal's wounds into another's. Something similar happens in dogs, where canine transmissible venereal tumour cells spread between mating partners via damage to their genitals. Shellfish pass cancer cells to each other through the water they live in. When a shellfish with cancer dies, it releases huge numbers of cancerous blood cells into the water. Other shellfish filter that water as they feed, and can pick up the cancer cells in the process.In each case, cancer cells break free from one body, travel to another and carry on living and dividing as cancer cell...