How_It_Works_Issue_99_2017

DID YOU KNOW? Any osedax worm you see will be female. The microscopic males live inside the females!
Osedax worms
These marine worms have the affectionate
nickname of ‘zombie worm’ thanks to their
penchant for eating bones. Indeed, the worm’s
name ‘osedax’ means ‘bone devourer’ in Latin.
Despite their gruesome name, these small
worms are an important part of the marine
ecosystem. After a ‘whale fall’, where a dead
whale drops to the sea floor, bringing essential
nutrients with it, the worms are drawn to the
carcass. They root themselves into the bone,
splaying feathery gills into the water, which
look like a sprouting flower. Related to the
tubeworms found on hydrothermal vents in the
deep sea, osedax are also full of symbiotic
bacteria. In return for a safe home within the
worm, the bacteria break down the whale bone
matter to provide the osedax with food.
Aye-ayes
Teeth
The aye-aye uses its evergrowing,
razor-sharp teeth to
tear into trees and branches to
get to the grubs inside.
Fur
Unusual for such a hot
climate, these lemurs
are covered in thick,
black, woolly fur
tipped with white.
Meet the lemur’s crafty, and
slightly creepy, cousin
Don’t look the aye-aye in the eye is advice
that Madagascar’s locals would ofer you.
It’s considered an omen of death if the
aye-aye points at you with its elongated middle
digit, but whether that’s true or not, these little
primates (which are actually the world’s largest
nocturnal primate) are incredibly weird. They
are placed in their own taxonomic family but are
classiied as a kind of lemur, sporting huge eyes
and ears, long, needle-sharp teeth that never
stop growing and the strangest ingers and toes
in the animal kingdom.
The aye-aye’s digits are long and spindly and
topped with long, sharp claws. The middle
inger is particularly elongated and
knobbly, protruding a few inches
longer than the rest. It has ball and
socket joints, allowing the middle
inger to swivel a bit like our
shoulder joints do, and this curious
appendage has a very speciic job.
Under the cover of night, the
aye-aye moves along dead branches
in the forest and taps its middle inger
on the tree bark. It’s feeling for the
reverberations of the mines made by its
favourite food, wood-boring insect larvae,
beneath the bark; a method that mimics
echolocation used by mammals like bats. The
middle inger is then poked into tiny holes to ish
out the prey with sharp ingernails. This method
of inding food means the aye-aye essentially
occupies the same niche as a woodpecker!
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Fingers and toes
Each tipped with a
sharp, pointed claw
(apart from the big
toes, which have flat
nails), these
appendages are the
aye-aye’s essential
hunting tools.
Arms and legs
These are all the same
length, making walking
on all fours easy. They
are also strong and agile
for life in the forest.
Nipples
The only primate to
have such an
arrangement, the
aye-aye’s nipples aren’t
located on the chest but
on the lower abdomen.
Osedax worms don’t
have mouths or
stomachs, and have to
absorb nutrients
“ The aye-aye’s digits
are long and spindly
and topped with
long, sharp claws”
How It Works | 029
© Alamy; Thinkstock