BBC Wildlife - UK (2019-12)

BBC Wildlife 69

on average 8.6 days shorter and survival
was hit, too – down by 5.1 per cent for every
degree of warming. Over the same period,
non-hibernating rodents were not affected.
Here in Britain, it has been shown that
hazel dormice are now hibernating for five
weeks fewer than they did 20 years ago.
Meanwhile, it is thought that warming
is having the same effect on hedgehogs.
Pat Morris, the UK’s hedgehog guru,
hassuggested mild weather
awakens the animals prematurely
inspring. It’s also possible
that temperate conditions
in autumn may encourage
females to breed late and
enter hibernation late, with
compromised fat reserves.
Among newts, the early
spring migration to ponds is now
a mid-winter event and reports
of frogs calling in January

proliferate. How will this affect them?

Nobody knows. Among insects, it is thought

that warmer winters might encourage

destructive pathogens to flourish, while it is

also possible that some flowers are blooming

too early, before the emergence of enough

bees to pollinate them. As with so many

aspects of climate science, cause and effect

are difficult to measure and prove.

One thing is for certain. Warming will

cause many changes, many of concern.

Maybe those fat dormice in Austria are on to

something. Long sleeps are a good idea. It’s

the shortened ones that cause the trouble.

FINDOUTMORE The dierent types of

deep sleep: bit.ly/2owXmrN

DOMINIC COUZENS has been a

professional wildlife writer for 25

years. He travels a lot and lives in

a house with otters in the back garden.

The hazel dormouse is the

only dormouse species

native to Britain. Below:

natterjack toads use sand

or mud to shelter them

from harsh temperatures.