Page 99 - BBC Wildlife Volume 36 #06

Q&A

Q BIRDS
Q INSECTS
How did shrikes learn to

impale prey? Males with bigger caches tend to interfere
breed with the earliest-arriving
females, producing more fledglings. glow-wor
A These hook-beaked They may even win two
birds are known for mates. By caching, a bird A Yes. Male glow-wo
skewering their can mark his territory, non-flying females by
insect and other hoard supplies for glow. This cold light is
small prey onto leaner times and by the chemical meta
spikes such store toxic prey, energy-storing molec
as thorns and such as lubber enzyme luciferase, an
barbed wire. grasshoppers, photosynthesis, releasing light photons into
They may have until the the night sky. Like moths, male glow-worms
developed the Shrikes: chemicals are attracted to artificial lights, which appear
Shrike: Michel Geven/Minden/FLPA;glow worm:Andy Sands/naturepl.com; illustration:Getty
technique by the thorn in they contain to confuse their navigation. The worry is that
the side of
accident, when decompose. The excessive lighting will distract them, preventing
many small
prey they were mammals. development of this them from finding the females in the rough,
wedging into technique may also grassy banks where they breed. Recent
forks of branches to have been an accident, experiments in a small Swiss town found that
manipulate, perhaps with males first impaling when road lighting was on, simple LED traps
because they lack strong the vivid insects to attract mates only received males in dark areas far from
talons, became stuck on before later discovering that they lamp posts, but when the lights were of, males
thorns. By repeatedly using became safe to eat. Liz Kalaugher occurred in all areas. The current thinking is
the same spikes, the birds that street lighting cuts ‘cheese holes’ in the
ended up with caches of food. beetles’ mating landscape.
Nowadays, males use these food Richard Jones
stores, along with display items
such as rags, snail shells and the Being very big is a
membrane-coated faecal sacs great way to avoid
produced by nestlings, becoming a target
for predators.
to attract females.

Q PALAEONTOLOGY

A D necks of sauropods acted like giant rakes, have driven physiological shifts towards larger
Dinosaurs were the largest species ever
l
t to walk the Earth. Some, like the sauropods, constantly sweeping in food as they swung bodies. Sauropod bones were also lightweight,
i
d
weighed around 90 tonnes (the equivalent from s eac hi h hollowed out by numerous air sacs extending
h
d
b
l
l
f
d
d
i
i
h
i
l
(
h
of 15 adult elephants) and make fascinating up foliage. Sauropods did not chew and had from the lungs, making a bigger body easier
examples of the extremities of biological specialised teeth for swallowing mouthfuls to support. Being huge also gave an advantage
engineering. There is no uncontroversial of food, stripped from plants. Their bulky against the large theropod dinosaurs and
explanation for their size, and scientists have bodies housed factory-like stomachs for highly could have been triggered by an evolutionary
numerous intriguing theories. The long efficient, massive-scale digestion, which might arms race against predators. Jon Tennant
June 2018 BBC Wildlife 99