— biologists herald this the fastest recovery of a land mammal in the history of the endangered species act. — feral pigs were eradicated from santa cruz, opening the door for island foxes to flourish, which they have. initially, it was thought that santa cruz island had a carrying capacity of approximately 1,200 to 1,500 island foxes, but estimates show a population infusion of 2,100 animals on the largest, most biodiverse island off the california coast.