Penguins Essay, Research Paper

Myopic little men in tuxedos, or highly efficient

land/water animals? Recent research indicates

there’s more to penguins than meets the eye. If

you’ve every wondered what it would be like to

be able to see as clearly under water as you can

on land, just ask the nearest penguin.Most aquatic

animals are short-sighted on land. Most terrestrial

animals (and that includes us) are far-sighted under

water. But researchers have discovered that

penguins can apparently see equally well in both

environments, because of the unique structure of

their eyes. Penguins have to be able to see well

under water because their diet consists mainly of

plankton, molluscs, crustaceans, and the inevitable

fish. Through a special slowing-down of their heart

rate they’re able, like many other diving animals, to

stay submerged long enough to search out and

chase whatever catches their fancy. On dry land,

it’s a different story-or has been up to now.

Waddling along on their flat little feet, eyes fixed

intently on the ground, penguins appear myopic,

inefficient and generally out of place. In fact the

reverse is true. During a recent stay on the

Falkland Islands, a Canadian researcher

discovered that penguins are able to recognize

individuals and navigate the rocky terrain on which

they live quite well. Long of body and short of leg,

they probably poke their heads forward as an aid

to balance. And as for looking at the ground,

they’re merely-like us-keeping an eye on where

they’re going. The human eye is adapted for aerial

vision, which is why scuba divers-or even you and

I in the local swimming pool-must wear goggles or

a face mask to re-introduce air in front of our eyes

in order to see clearly. Among vertebrates in

general, the bird eye is frequently described as the

most efficient. Its superior quality, combined with

the fact that a large number of birds-cormorants,

pelicans, seagulls, even ducks, as well as

penguins-get their food from water, obviously

deserved research beyond that possible in a

controlled environment such as an aquarium or

zoo. Professor Jacob Sivak of the University of

Waterloo and his associate, Professor Howard

Howland of Cornell University, had a chance to

do that research recently. Their trip had but one

purpose-to study the structure of penguins’ eyes

while observing their natural habitat. The Falkland

Islands, off the coast of Argentina, offered this

opportunity, being one the few areas outside

Antarctica where penguins can be found in large

numbers. Three of the 16 known species were

located there: the Gentoo, which live on flat areas

right off the beach; the Magellan (also called

Jackass), which live in burrows; and the

Rock-hoppers, which live among the rocks along

the cliffs. The Rock-hoppers were by far the most

common, having a population of well over

100,000. The general rule is, the smaller the

penguin, the meaner the temperament, and the

researchers did witness the odd fight. Their

flippers may look pretty useless out of water, but

it’s not smart to play around with a penguin. Hel’ll

stand his ground in a face-off and if you’re foolish

enough to get too close, those flippers can knock

you flat. Dr. Sivak and his associate, however,

had little trouble. Rock-hoppers always

congregate in fairly tight groups, as a defense

against predatory birds such as the skua (a large

seagull that thinks it’s a hawk), and two more

upright figures in their midst didn’t seem to bother

them. Standing as close to their subjects as 0.3m,

the scientists used two devices: one, developed by

Professor Howland, to take photographs of the

penguins’ eyes; the othger, developed by Dr.

Sivak, to shine a series of concentric circles on the

cornea and give a measurement of how reflections

of objects are altered by curvature of the eye.

Despite the fact all the work had to be done at

night-the only time the penguins’ pupils were

dilated enough-the results were worth it.

Comparison of the photographs with similar

photos of human eyes, and study of the internal

structure of the eyes of creatures discovered killed

by seal lions, proved the scientists’ theory that the

penguin’s eyes are the secret of its survival. In

general terms, a penguin eye and a human eye are

almost identical. Both have the same components

necessary for vision-a cornea through which light

can enter; an iris which controls the amount of light

that enters; and a crystalline lens that focuses the

light onto the back of the eye where a specialized

membrane, the retina, receives it and passes the

message along the optic nerve to the brain for

interpretation. In the penguin eye, hoever, there

are many subtle differences. The cornea, for

example, is markedly flattened compared to ours

– so much so that it almost resembles a

window-pane. This greatly alters the angle at

which light can enter the eye and is very important

for underwater swimming, when light enters the

eye obliquely through a medium (water) whose

density is quite different to the density of air. The

penguin iris is controlled by a very powerful

muscle which is able to drastically alter the shape

of the lens attached to it, depending on whether

the penguin is in or out of the water. The lens,

comparatively larger than ours and differently

shaped, focuses the light coming through the

flattened cornea onto the retinal body at the back

of the eye. In this way, the penguin eye adapts to

whatever medium it happens to be in at the time.

Interestingly, there was no evidence of eye

problems (apart from one incident of blindness

due to injury) in the group of penguins studied. Of

course penguins don’t read, watch TV or

encounter any of the numerous irritants we

land-bound animals subject ourselves-or are

subjected-to during our lifetime. Both the testing

devices and methods used in this study are easily

adaptable for use with human eyes, paving the

way for fast, easy identification of eye problems.

Also, the researchers hope that the insights they’ve

gained into how animals deal with two

environments may lead to knowledge of how

humans, in the future, might do likewise.