The Chinese Year of the Rat, the first in the lunar cycle, begins 7 February. Rats are arguably the most damaging invasive animal, doing massive damage to crops and biodiversity and carrying many zoonotic diseases. Most famously they are associated with the pandemics of bubonic plague, responsible for wiping out maybe a third of the population on Europe in the Middle Ages.
By my reckoning nine of the 12 Chinese horoscope animals are feral somewhere. What do you think?
Rat: ricefield rats in South East Asia eat the equivalent of the caloric intake of Indonesia every year!
Ox: regeneration of native trees in Hawaii can be completely stopped by feral cattle.
Tiger: I don't know of any feral tiger reports - never a species we think of as overabundant.
Rabbit: Australia's worst Christmas present, arriving 1859.
Dragon: I don't know of any but still 280,000 hits on Google
Snake: the brown tree snake is Guam's worst enemy
Horse: Wikipedia lists 13 different feral horses from Portugal to Namibia to Nova Scotia to new Zealand.
Goat: the "Judas Goat" technique is very effective in tracking down goats and is widely used in eradication programs.
Monkey: rampant monkey populations aggressively demanding food are Hong Kong's worst feral species.
Rooster: this was one of the three I left off the list but Google gives me 36,000 hits on "feral rooster" - mainly keeping people wake on Hawain islands.
Dog: rabies still kills over 50,000 people annually with feral dogs a major source.
Pig: we might have five times more feral pigs than domestic ones in Australia!
So let's make it 10 out of 12.