African Nature Notes and Reminiscences 5

African Nature Notes and Reminiscences 5

ILLUSTRATIONS

 

 

"UNFORTUNATELY, ONE OF THESE TERRIFIC BLOWS, VERY PROBABLY THE FIRST

AIMED AT THE LEOPARD WHICH SEIZED THE CALF, HAD STRUCK THE LITTLE

CREATURE ON THE LOINS AND BROKEN ITS BACK" _Frontispiece_

 

FACING PAGE

 

"HE HAD EVIDENTLY BEEN SITTING OR LYING BY A FIRE WHEN CAUGHT" 53

 

PLATE SHOWING DIFFERENCES IN THE DEVELOPMENT OF THE MANE IN LIONS

INHABITING A COMPARATIVELY SMALL AREA OF COUNTRY IN SOUTH AFRICA 76

 

"A PICKED MAN OF DAUNTLESS HEART ... WOULD RUSH FORWARD ALONE...." 93

 

"ON THE SECOND NIGHT THEY ONCE MORE LEFT IT ALONE, BUT ON THE THIRD

THEY DEVOURED IT" 103

 

"SUCH OLD BUFFALO BULLS WERE VERY SLOW ABOUT GETTING OUT OF ONE'S

WAY" 146

 

PHOTOGRAPHS OF A STRUGGLE BETWEEN A RHINOCEROS AND A CROCODILE:

 

No. 1. Shows the Rhinoceros holding its own, but unable to reach the

bank 202

 

No. 2. Shows the Rhinoceros still struggling, but in deeper water 202

 

No. 3. Shows the Rhinoceros after it had turned round, and just

before it got into deep water and was pulled under 202

 

"I KNEW IT WAS A MALE INYALA--THE FIRST THAT MY EYES HAD EVER LOOKED

UPON" 242

 

"THE GEMSBUCKS WERE NOW GOING AT THEIR UTMOST SPEED, AND WHEN I HAD

PASSED THE ZEBRAS WERE STILL SIXTY OR SEVENTY YARDS IN FRONT OF

ME" 258

 

"MY GUN-CARRIER HURLED ANOTHER LUMP OF BURNING WOOD AT OUR VISITOR"

273

 

THE LAST OF SOUTH AFRICA'S GAME HAUNTS 302

 

 

 

 

CHAPTER I

 

NOTES ON THE QUESTIONS OF PROTECTIVE COLORATION, RECOGNITION MARKS,

AND THE INFLUENCE OF ENVIRONMENT ON LIVING ORGANISMS

 

Harmony of colour in nature--Theory of protective coloration--Sexual

selection--Conspicuous colours not harmful--The influence of

environment--The leucoryx--The Barbary sheep--The Sardinian

moufflon--African butterflies--Coloration of the musk ox

and caribou--Arctic hares and foxes--Coloration of mammals

in the Yukon Territory--The chamois in winter--Examples of

conspicuous coloration in African mammals--Colour not always

protective--Carnivorous animals usually hunt by scent--Wild

dogs and wolves--Wild dog and sable antelope--Sense of smell

in herbivorous animals--Sight of antelopes--Experience with

waterbuck--Dull sight of caribou--Demeanour of wild animals when

alarmed--Small antelopes--Lions--Large antelopes--Difficulty of

seeing wild animals sometimes exaggerated--Powers of sight of

Bushmen--Colour not protective against animals which hunt by

night and by scent--Animals in motion easy to see--Restlessness

of wild animals--Lions attacking bullocks--Zebras the principal

prey of lions since the disappearance of buffaloes--Appearance of

zebras--Undoubtedly conspicuous animals in open country--Zebras

by moonlight--Strong smell of zebras--Conspicuous antelopes in

East Africa--Effect of the juxtaposition of black and white--Bold

coloration of the sable antelope.

 

 

Although there are certain striking exceptions to the general rule,

yet, broadly speaking, it cannot be gainsaid that living organisms are

usually coloured in such a way as to make them difficult of detection

by the human eye amongst their natural surroundings. Every collecting

entomologist knows how closely certain species of butterflies when

resting with closed wings in shady forests resemble dead leaves, or

moths the bark of trees. Birds too, especially those which nest on the

ground, often harmonise with their surroundings in a most marvellous

way.

 

In the open treeless regions within the Arctic Circle, as well as on

bare mountain ranges, nearly all the resident species of animals and

birds turn white in winter, when their whole visible world is covered

with an unbroken mantle of pure white snow, and become brown or grey

during the short period of summer.

 

In treeless deserts again within the tropics, where the rainfall is

very scanty and the climate excessively hot and dry, with intense

sunlight throughout the year, all resident living organisms, mammals,

birds, reptiles, and insects, are found to be of a dull coloration

which harmonises in the most wonderful way with the sandy or stony soil

on which they live. It is also very often the case that animals which

live in forests where the foliage is not too dense to allow the sun to

penetrate are spotted or striped, whilst those which live in really

thick jungle or amongst deep gloomy ravines are of a uniform dark

coloration.

 

Now a most interesting question arises as to the true causes which have

brought about the extraordinary variations of colour to be seen in

living organisms inhabiting different parts of the world.

 

It is, I believe, the general opinion of modern naturalists that,

putting aside cases where brilliant colours may have been produced

amongst birds and insects by the action of the law of sexual selection,

the coloration of all living organisms is protective, "serving," as

that distinguished naturalist Mr. Alfred Russel Wallace puts it, when

discussing the subject of the coloration of mammals, "to conceal

herbivorous species from their enemies, and enabling carnivorous

animals to approach their prey unperceived."

 

Many very striking facts can be adduced in support of this theory,

and no doubt it is of advantage to most species of mammals, birds,

reptiles, and insects to harmonise in colour with their surroundings;

but there are many instances in nature, especially amongst birds and

insects, where a very striking and conspicuous coloration does not

appear to have been prejudicial to the life of a species.

 

The highly decorative but very conspicuously coloured plumage to be

seen in the males of many species of birds, especially during the

breeding season, was considered by the immortal Darwin to be due to

the influence of sexual selection, and whatever may be urged against

the correctness of this theory, it is supported by a long array of

indisputable facts.

 

Great, however, as is the divergence between the plumage of the males

and females in many species of birds, not only during the breeding

season, but in a great number of cases at all times of year, and

however gaudy and conspicuous the coloration of the former may be

compared with that of the latter, such conspicuous coloration never

appears to be prejudicial to the life of a species, though in some

cases the brighter coloured male assists the female in incubation, and

it would thus appear that in all such cases the sombre coloured plumage

of the female was not absolutely necessary for purposes of protection

against enemies.

 

I therefore think that if it is admitted that bright and conspicuous

colours have been evolved in living organisms through the action of the

law of sexual selection, without detriment to the life of the species

in which such conspicuous colours are shown, it must be conceded that

a coloration harmonising with its surroundings is not a necessity of

existence in all cases to all species of mammals, birds, reptiles, and

insects, and that it is therefore quite possible that where living

organisms agree very closely in colour with their surroundings, such

harmonious coloration may have been produced by some other agency than

the need for protection by colour, and I would suggest that in addition

to the influence exerted in the evolution of colour in living organisms

by the action of sexual selection, and the necessity for protection

against enemies, a third factor has also been at work, which I will

call the influence of environment.

 

It is worthy of remark, I think, that in hot, dry deserts, where the

climatic conditions are stable, and where the general colour of the

landscape is therefore very much the same all the year round, _all_

the resident species of mammals, birds, reptiles, and insects are what

is called protectively coloured, that is to say, they are _all_ of a

dull brown or greyish coloration,[1] which harmonises beautifully with

their parched, dull-coloured environment. In the leucoryx, the Saharan

representative of the gemsbuck of South-Western Africa, all the black

markings which are so conspicuous in the latter animal have disappeared

or become pale brown, whilst the general colour of the body has been

bleached to a dirty white. Now, no one can persuade me that if the

leucoryx were coloured exactly like its near relative the gemsbuck,

it would suffer one iota more, in the open country in which it lives,

from the attacks of carnivorous animals than it does at present, and I

therefore believe that the faded colour of the leucoryx, as compared

with that of the gemsbuck or the beisa antelope, has not been brought

about in order to serve as a protection against enemies, but is

directly due to the influence of its desert environment, and constant

exposure to strong sunlight on treeless plains. Again, from the point

of view of a carnivorous animal hunting for food by daylight and by

sight, no two countries could be more alike than the open karoos of the

Cape Colony and the plains in the neighbourhood of Lakes Nakuru and

Elmenteita in British East Africa, where the grass is always kept very

short by the large herds of game, as well as by the cattle, sheep, and

goats belonging to the Masai, which pasture there. Before the advent

of Europeans, the carnivorous animals inhabiting the Cape Colony were

exactly the same as those found to-day in East Africa, viz. lions,

leopards, chetahs, wild dogs, and hyænas. In both districts lions

were once numerous, and in both zebras formed the principal food of

these carnivora. But whereas _Equus granti_, the form of zebra found

on the plains near Lake Nakuru, is the most brilliantly coloured

representative of the genus to which it belongs, with jet black

stripes on a pure white ground, the now extinct form of zebra--_Equus

quagga_--which once abounded on the plains of the Cape Colony, was of

a dull grey brown in ground colour, with darker brown stripes on the

head, neck, and fore-part of the body alone. Now, these two races of

zebras, both living on bare, open plains, could not both have been

coloured in the best possible way to escape being seen by the lions

which constantly preyed upon them. If, as has been contended, the

juxtaposition of the black and white stripes in Grant's zebras renders

these animals not only inconspicuous, but almost invisible under strong

sunlight on an open plain, and is, in fact, the supreme triumph of

protective coloration in large mammals, why had the quaggas of the

Cape Colony become dull brown, for they also lived on open plains in

strong sunlight, and needed protection from the lions every bit as much

as their congeners of East Africa? Moreover, I think all naturalists

and embryologists are agreed that _Equus quagga_ was the descendant of boldly striped ancestors.