The frogs are vociferous; and now if they were more silent they would last longer.
Of all the reptiles known to me, only two utter vocal sounds,--the alligator and the elephant tortoise. The former roars or bellows, the latter grunts.
IV
THE MOST INTELLIGENT ANIMALS
To the professional animal-man, year in and year out comes the eternal question, "Which are the most intelligent animals?"
The question is entirely legitimate. What animals are the best exponents of animal intelligence?
It seems to me that the numerous factors involved, and the comparisons that must be made, can best be expressed in figures.
Opinions that are based upon only one or two sets of facts are not worth much. There are about ten factors to be taken into account and appraised separately.
In order to express many opinions in a small amount of s.p.a.ce, we submit a table of estimates and summaries, covering a few mammalian species that are representative of many. But, try as they will, it is not likely that any two animal men will set down the same estimates. It all depends upon the wealth or the poverty of first-hand, eye-witness evidence. When we enter the field of evidence that must stand in quotation marks, we cease to know where we will come out. We desire to state that nearly all of the figures in the attached table of estimates are based upon the author"s own observations, made during a period of more than forty years of ups and downs with wild animals. ESTIMATES OF THE COMPARATIVE INTELLIGENCE AND ABILITY OF CERTAIN CONSPICUOUS WILD ANIMALS, BASED UPON KNOWN PERFORMANCES, OR THE ABSENCE OF THEM.
[Footnote: To the author, correspondence regarding the reasons for these estimates is impossible.]
[beginning of chart]
Perfection in all=100 [list of categories below are written vertically above the columns, with the last column unnamed and representing a total score of animal intelligence/1000]
Hereditary Knowledge Perceptive Faculties Original Thought Memory Reason Receptivity in Training Efficiency in Execution Nervous Energy Keenness of the Senses Use of the Voice
Primates
Chimpanzee ... ... ...100 100 100 100 75 100 100 100 100 50 925 Orang-Utan ... ... ...100 100 100 75 100 75 100 75 100 25 850 Gorilla... ... ... ... .50 50 50 50 75 25 25 50 100 25 500
Ungulates
Indian Elephant ... ...100 100 100 100 100 100 100 75 50 25 850 Rhinoceros... ... ...25 25 25 25 25 0 0 25 25 0 175 Giraffe ... ... ... ... .50 25 25 25 25 25 0 25 100 0 300 White-Tailed Deer ...100 100 100 25 50 0 0 100 100 0 575 Big-Horn Sheep ... ...100 100 50 25 50 0 0 100 100 0 525 Mountain Goat... ... .100 100 100 25 100 0 0 100 100 0 625 Domestic Horse... ...100 100 100 75 75 75 75 100 100 50 850
Carnivores
Lion ... ... ... ... ... .100 100 50 75 50 75 50 100 100 25 725 Tiger ... ... ... ... ...100 75 50 50 50 25 25 100 100 0 575 Grizzly Bear ... ... ...100 100 50 25 50 75 50 75 100 25 725 Brown Bear (European)100 100 50 25 50 75 50 75 100 25 650 Gray Wolf ... ... ... . . 100 100 100 25 75 00 100 100 25 625 Coyote ... ... ... ... . . 100 75 50 25 50 0 0 75 100 25 500 Red Fox ... ... ... ... . 100 100 50 75 100 0 0 100 100 25 650 Domestic Dog ... ... ...50 100 75 75 75 75 100 100 100 100 850 Wolverine ... ... ... . .100 100 100 25 100 0 75 100 100 0 700
Beaver ... ... ... ... . .100 100 100 25 100 0 100 100 100 0 725
According to the author"s information and belief, _these are "the most intelligent" animals:_ The Chimpanzee is the most intelligent of all animals below man. His mind approaches most closely to that of man, and it carries him farthest upward toward the human level. He can learn more by training, and learn more easily, than any other animal.
The Orang-Utan is mentally next to the chimpanzee.
The Indian Elephant in mental capacity is third from man.
The high-cla.s.s domestic Horse is a very wise and capable animal; but this is chiefly due to its age-long a.s.sociation with man, and education by him. Mentally the wild horse is a very different animal, and in the intellectual scale it ranks with the deer and antelopes.
The Beaver manifests, in domestic economy, more intelligence, mechanical skill and reasoning power than any other wild animal.
The Lion is endowed with keen perceptive faculties, reasoning ability and judgment of a high order, and its mind is surprisingly receptive.
The Grizzly Bear is believed to be the wisest of all bears.
The Pack Rat (_Neotona_) is the intellectual phenomenon of the great group of gnawing animals. It is in a cla.s.s by itself.
The White Mountain Goat seems to be the wisest of all the mountain summit animals whose habits are known to zoologists and sportsmen.
A high-cla.s.s Dog is the animal that mentally is in closest touch with the mind, the feelings and the impulses of man; and it is the only one that can read a man"s feelings from his eyes and his facial expression.
The Marvelous Beaver. Let us consider this animal as an illuminating example of high-power intelligence.
In domestic economy the beaver is the most intelligent of all living mammals. His inherited knowledge, his original thought, his reasoning power and his engineering and mechanical skill in constructive works are marvelous and beyond compare. In his manifold industrial activities, there is no other mammal that is even a good second to him. He builds dams both great and small, to provide water in which to live, to store food and to escape from his enemies. He builds air-tight houses of sticks and mud, either as islands, or on the sh.o.r.e. When he cannot live as a pond-beaver with a house he cheerfully becomes a river-beaver.
He lives in a river-bank burrow when house-building in a pond is impossible; and he will cheerfully tunnel under a stone wall from one-pond monotony, to go exploring outside.
[Ill.u.s.tration: CHRISTMAS AT THE PRIMATES" HOUSE Chimpanzees (with large ears) and orang-utans (small ears). The animal on the extreme right is an orang of the common caste]
He cuts down trees, both small and large, and he makes them fall as he wishes them to fall. He trims off all branches, and leaves no "slash" to c.u.mber the ground. He buries green branches, in great quant.i.ty, in the mud at the bottom of his pond, so that in winter he can get at them under a foot of solid ice. He digs ca.n.a.ls, of any length he pleases, to float logs and billets of wood from hinterland to pond.
If you are locating beavers in your own zoo, and are wise, you can induce beavers to build their dam where you wish it to be. This is how we did it!
We dug out a pond of mud in order that the beavers might have a pond of water; and we wished the beavers to build a dam forty feet long, at a point about thirty feet from the iron fence where the brook ran out. On thinking it over we concluded that we could manage it by showing the animals where we wished them to go to work.
We set a l2-inch plank on its edge, all the way across the dam site, and pegged it down. Above it the water soon formed a little pool and began to flow over the top edge in a very miniature waterfall. Then we turned loose four beavers and left them.
The next morning we found a cart-load of sticks and fresh mud placed like a dam against the iron fence. In beaver language this said to us:
"We would rather build our dam here,--if you don"t mind. It will be easier for us, and quicker."
We removed all their material; and in our language that action said: "No; we would rather have you build over the plank."
The next night more mud and sticks piled against the fence said to us,
"We really _insist_ upon building it here!"
We made a second clearance of their materials, saying in effect:
"You _shall not_ build against the fence! You _must_ build where we tell you!"
Thereupon, the beavers began to build over the plank, saying,
"Oh, well, if you are going to make a fuss about it, we will let you have your way."
So they built a beautiful water-tight dam precisely where we suggested it to them, and after that our only trouble was to keep them from overdoing the matter, and flooding the whole valley.
I am not going to dwell upon the mind and manners of the beaver.