World_of_Animals_Issue_46_2017
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<strong>Animals</strong> answers<br />
Can it really rain frogs?<br />
Surprisingly, yes. Frogs, fish and other<br />
small animals can be carried into<br />
the atmosphere by tornadoes before<br />
plummeting down again when the storm<br />
subsides. In 2000, the BBC reported fish<br />
raining down in Norfolk after a minitornado<br />
travelled in from the sea.<br />
These swirling winds form over land,<br />
and if they travel over water they can<br />
create a waterspout with an area <strong>of</strong> low<br />
pressure in the centre. This pressure<br />
difference draws liquid and other objects<br />
upwards into the air, occasionally<br />
carrying aquatic animals away from<br />
their homes. As the winds start to drop,<br />
the heaviest objects fall first, followed<br />
later by the lighter ones.<br />
It really has<br />
been known<br />
to rain frogs<br />
Haemocyanin<br />
Hemerythrin<br />
Why do crabs and spiders have blue blood,<br />
and does blood come in any other colours?<br />
Haemoglobin<br />
Chlorocruorin<br />
We are used to blood being red, but the animal kingdom has<br />
come up with a rainbow <strong>of</strong> other options.<br />
Our own blood contains the oxygen-carrying molecule<br />
haemoglobin. It is made from four units <strong>of</strong> haem, each <strong>of</strong><br />
which contains an atom <strong>of</strong> iron. The molecule absorbs certain<br />
wavelengths <strong>of</strong> light, giving it its distinctive red colour. When<br />
oxygen is bound, it appears bright, but without oxygen it’s a<br />
deeper hue.<br />
Crabs, lobsters, spiders, squid and octopuses have blue blood<br />
because they use a copper-based system to carry gas to their<br />
tissues. The molecule is known as haemocyanin and, without<br />
oxygen, it is colourless. When the gas binds, the colour changes.<br />
Some marine worms have iron-based systems with even<br />
wilder colours. Green blood is the result <strong>of</strong> a molecule called<br />
chlorocruorin, while a slightly different iron-containing molecule<br />
called hemerythrin is purple.<br />
And, some animals don’t have any oxygen-carrying pigments<br />
at all. In very cold water, there’s so much dissolved oxygen<br />
that colourful pigments aren’t necessary, so some deep sea<br />
creatures have completely transparent blood.<br />
© Thinkstock<br />
Crabs have copper<br />
in their blood<br />
Q.Why are<br />
March hares mad?<br />
Find out at…<br />
animalanswers.co.uk
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