The Rural Voice, 1993-07, Page 38A stranger among us
Climatic changes bring opossum to Ontario
by Wayne Kelly
Residents of southern Ontario have mixed feelings about
the apparent shift of weather patterns in this part of the
world. But the arrival of milder, more open winters in our
area has meant the arrival of something else — new or
previously uncommon species of wildlife.
One such arrival is the Virginia opossum.
While not totally unknown in the province, the
appearance of the opossum is directly related to our
weather.
Pud Hunter, a wildlife biologist at the Aylmer office of
the Ministry of Natural Resources, describes the opossum
as "an opportunist".
"This is an animal that displays a very opportunistic
mode of life," Hunter says. "It does not historically inhabit
this area but seems to come into Ontario in waves that
correspond with changing weather."
The opossum ranges through the eastern half of the
United States and south into Mexico and South America,
but since 1850 it has appeared sporadically in southern
Ontario. Detailed records show it has invaded this area on
at least four occasions — about 1850-60, 1890-1910, 1930-
35 and from 1980 onward — with the most recent invasion
being heavier and more extensive than previous ones.
"The harsh, severe winters we experienced from the
1940s to the end of the 1970s seem to have moderated for
the time being," Hunter said. "The past decade of milder
winters has indeed lessened the stress on wildlife
populations in general."
A unique animal, the opossum is the only marsupial or
pouched mammal to live outside Australia. With a
gestation period of 13 days, up to 21 young may be born.
At birth they are the size of a white bean, blind, naked and
poorly developed except for a single feature: the clawed
front feet. With these claws they pull themselves through
the mother's fur to the pouch where perhaps only a dozen
will attach themselves to the existing nipples. The rest die.
Remaining in the travelling nursery for two months,
they grow to the size of small mice, emerging then to ride
and cling to the back and sides of the mother. A full-grown
adult is about the size of a small cat, gray to black to dusty -
white in colour, bare black ears, flesh -coloured feet, sharp
claws, powerful jaws studded with 50 teeth and a naked,
rat -like tail.
The opossum's diet may be one reason for its tenacious
existence. Nearly as omnivorous as the coyote, the
opossum eats rodents, insects, worms, grubs, birds, eggs,
meat, fruit and berries. Not presently considered a pest by
most farmers, it has a benefit as an insect controller since
its food of choice is in the form of crickets, grasshoppers,
beetles and other larvae.
According to Hunter, the opossum has few natural
predators.
"Certainly coyotes and dogs will go after this critter, but
the human trapper is likely the most serious threat it
34 THE RURAL VOICE
The opossum has spread throughout southern Ontario.
experiences. True, they may get into a hen house and cause
problems, but they will more often avoid domestic
livestock, thus removing most reasons to view them as
pests we have to control."
Mike Malhiot, Ministry of Natural Resources, a
biologist for Huron and Perth counties, reports the first