BBC Wildlife - UK (2021-12)

94 BBC WILDLIFE December 2021

DAVE HAMILTON ANSWERS

One creature eating a certain type of

food doesn’t make it safe for another.

Birds and animals evolve different

mechanisms over time to break down

poisons, usually in the liver and kidneys.

For example, during a time of famine

some 5,000 years ago, some humans –

mostly in western Europe – developed

an enzyme to break down cow’s milk.

We can therefore hypothesise that

a similar evolutionary stimulus would

have allowed squirrels to eat death-cap

mushrooms and nightshade berries.

Likewise, many species of bird have

adapted to eat mistletoe and holly,

two berries that are poisonous to

humans. Interestingly, mistletoe

berries produce a sticky substance in

the digestive tract that’s difficult for

birds to excrete. When it’s time for

an individual to defecate, it has

to ‘wipe’ its bottom along the

branch it’s perched upon to

help draw the gluey waste out.

This, in turn, helps to disperse

mistletoe seeds.

How do birds eat

berries that poison us?

FAST ANSWERS

Why does the

eyelash viper

have ‘eyelashes’?

The eyelids of all snakes are fused

together to form a transparent

protective shield over the eyeball,

so an eyelash viper’s lashes are

certainly not for batting. Comprised

of elongated scales, their function

remains mysterious. They may provide

additional eye protection as the

viper pushes through dense tropical

American vegetation, or they may

help break up the ambush predator’s

serpentine outline as it lies in wait for

passing prey. SB

What’s the

difference between

a bog and a fen?

The main difference is that a bog is

fed by rainwater, while a fen is fed

by groundwater. Since groundwater

contains more nutrients and minerals

than rainwater, a fen can support a

wider range of wildlife. The UK’s best

known is arguably Wicken Fen in

Cambridgeshire, home to a whopping

9,175 recorded species. SM

Who are Adélie

penguins named

after?

These handsome birds were

named by French naval officer

Jules Dumont d’Urville (who

discovered the birds in 1840)

in honour of his wife, Adéle.

Cape Pepin and Adélie Land,

both in Antarctica, also

bear her name. After

spending his life at

sea charting new

territory, Jules died

• with Adéle – in
  his native France at
  the age of 51, in the 1842
  Versailles rail disaster. SM

Mistletoe berries are

poisonous to us but

perfectly edible to

the species that have

evolved to digest them

Q A