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InFocus

Raccoon dogs: an invader in waiting?

Our conservation correspondent considers the growing numbers of these dogs and their spread from Asia.

ON THE FACE OF IT,
RACCOON DOGS
(Nyctereutes
procyonoides
) are incredibly cute and
one can see why someone might want
to keep one as a pet. I have handled
a tame raccoon dog
and it was amazingly
friendly and engaging.
It was apparently taken
out for walks on the
beach and interacted
normally with the more
traditional pet dogs it
met. No reason not to
keep one as a companion then? Well
think again.

Raccoon dogs are natives of East
Asia which includes south-east Russia,
China, Mongolia, Japan, Korea and as
far south as Vietnam. Being true canids
they are not closely related to raccoons
but the similarity of their facial
markings and colouration to that of
raccoons gives them their name. They
are considered to be closely related
to primitive canids and are the only
canid species that undergoes a type
of hibernation during periods of very
cold weather.

Unusually they are also
considered to be monogamous with the male playing a big part in rearing
the young. Indeed, introductions to
other countries that involved the
release of pregnant females only were
far less successful than those when pairs of males and
females were released.
This was thought to
be due to the relative
lack of success of cub
rearing by lone females.

In their native
countries, raccoon dog
numbers have been reduced in places through over-hunting
for the fur trade, but in many areas
where they have been introduced
(originally to produce a wild “crop” for harvesting for their fur) they are
thriving. This is presenting ecological
problems, particularly for some native
species that fall easy prey to them.

Populations increasing

Introduced raccoon dogs are now
abundant in western Russia, the Baltic
countries and Finland, with spring
populations in Finland estimated to be
around 250,000 animals. They are also
increasingly found in Germany and

Poland with thousands shot by hunters
each year. And they have spread to
Hungary, Romania, Switzerland and
the Netherlands as well.

Sweden too now has raccoon dogs
spreading west from Finland and here
an intensive control programme is
under way, not just to try to halt its
spread but to eliminate it from the
country.

They are considered to be a serious
threat to many native bird species,
particularly ground-nesting birds, and
amphibians. They are omnivorous and
will eat virtually anything available,
and because they breed so rapidly,
numbers can grow explosively, often
out-competing the native European
badger and fox.

They are commonly predated by
wolves and lynx where numbers of
these predators are high, but over
much of northern and western Europe
this is not the case and they have no
natural enemies in these areas.

Sweden’s eradication programme
began around 10 years ago and today
makes use of the so-called “Judas
animals” approach. These are animals
that have been captured and sterilised and then released with radio collars
that allow them to be tracked. When
they stop moving it is likely to be
because they have found a mate and
they are then followed and any wild
mate is humanely destroyed.

The use of “Judas animals” was
a technique successfully used by the
Ecuadorian government to eradicate
goats from some of the Galapagos
Islands.

Likely to thrive

The significance to the UK is that
there are already raccoon dogs in the
country as pets and it is likely that
some will eventually escape or be
illegally released.

With no natural predators here they
are likely to thrive and their impact on
native species, while only speculation,
could be dramatic.

We have the examples of American
mink and the grey squirrel to illustrate
what has happened in the past. This is
a potential “invader in waiting” and it
is to be hoped that UK conservation
bodies are ahead of the game with
plans in place to deal with the situation
should it at any time arise.

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