Sanctuary Asia — January 2018

Meadows of

the Sub-Antarctic

Cloaks of Invisibility

Sanctuary | Natural History

The breeding grounds of Adelie Penguins are located southernmost than any other species of penguin. They are known to walk

almost 96 km. on certain occasions to reach their traditional breeding grounds.

Did You Know?

How does any organism manage to survive in the harsh,

unforgiving climes of the Antarctic and the sub-Antarctic islands?

The truth is, there are some tough and resilient beings that not

just survive, but thrive there. We are talking about ‘megaherbs’ of

the perpetually-freezing islands of the sub-Antarctic. While our

imagination paints a picture of a barren land, devoid of colourful

fl owering plants, the reality can take one’s breath away. You will

be surprised at the complete contrast in the form of bright and

colourful plant species that can be found growing, adapting and

evolving here.

Well-known British botanist, Sir Joseph Dalton Hooker, once

related the fl oral scenario of the Antarctic on an expedition as

“producing a fl oral display second to none outside the tropics”.

The coping mechanism in some of the herb species such as

Pleurophyllum speciosum exhibited surface temperature to be

around 4^0 C to 10^0 C higher than the surrounding air temperature.

Hairs on the leaf ridges trapped heat, darker colours absorbed

more solar radiation and large leaf sizes helped in taking in more

heat. These adaptations are defi nitely not exclusive to the plants in

the sub-Antarctic islands and are seen even in ‘giant herbs’ of the

tropical alpines such as Hawaii and Andes among others. Though

not closely related, plants of the sub-Antarctic and the alpines

resorted to similar adaptations and both have survived to tell their

tales, still largely unheard and little understood.

In nature, colour has purpose – and it’s not just the

presence of colour, even the absence of it. Deep in the dark

abysses of the oceans live some spectacular species of animals,

who have developed ingenious ways of becoming ‘invisible’ to

give their predators the slip.

Now, being transparent is about letting light pass right

through the body. Or even the ability to bend light in

such a way that none of it refl ects back to the observer’s

eyes rendering oneself invisible. The glass octopus

Vitreledonella richardi, for example, makes up for its

partly-transparent body with certain opaque organs by

minimising the shadows it casts, which could otherwise betray

its position. About 200 to 1,000 m. deep in the sea, the glass

squid (Cranchiidae family) can pull off the vanishing act by

using photophores found near its eyes. It produces light that

almost perfectly matches the amount of light falling on it from

all sides, thus blending its almost entirely transparent body

with the surrounding light.

Hyperiid amphipods apply ‘nanotechnology’ that allow

them to bend and interfere with light thereby not allowing

it to be refl ected. Close observation of the Hyperiid species

has revealed several microscopic protuberances in the form

of bumps and spheres, of about 100 to 300 nanometres in

size. Interestingly, scientists now think that these microscopic

structures could really be bacteria attached to the body, which

cloak the host animal with ‘invisibility’!

A glass squid makes up for its non-transparent

optical organs by using its photophores, which help

make it entirely 'invisible'.

Transparency works as a near-perfect

defensive feature for the glass octopus.

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