The opossum (in fact, "possum") imported into New Zealand for its fur, have colonized all the country to the point that its population is now 70 millions, ie about 20 times higher than humans !! He devours throughout the forest, eating despite its small huge kilos of green/day, can climb to the treetops of multi centenarians trees and destroying its young leaves. It reproduces at a rapid pace, and worse, very cleaver, eluding the poison traps -ultra-dangerous to all other animals and even for men- .. Nothing to do against. Hunters specialists (!) at gold price hunt its in vain, a terrible massacred of thousand of these cute animals without it changing much. Worse, it transmits tuberculosis to cow cattles. "Researchers" has imagined.. to sterilize females, simple operation they say ... except that, to be effective, it will be done at the 3/4 of these, just 5 millions!! to capture, operate, and release (!) Great !