In non-humans, a few types of transmissible cancer have been described, wherein the cancer spreads between animals by transmission of the tumor cells themselves.
The cytotrophoblast layer spreads and contacts the cytotrophoblast layers of neighboring anchoring villi, creating a continuous layer called the cytotrophoblastic shell.
He also spreads the sweepings and unsaleable leftovers from his barley crop on his fields in winter and believes this may have helped attract the birds.
