Popular Science Monthly/Volume 43/September 1893/The Psychology of Lizards
By M. J. DELBŒUF.
I PUBLISHED two articles in February and October, 1891, telling of two ocellated lizards which I had captured in May, 1890 — one at Port Bon, on the borders of Spain, the other on the banks of the Tarn, near Peyrdean, France. I described their characteristic differences at length, telling how the former lizard was bold, snappish, suspicious, and stupid; and the latter was timid, gentle, confiding, and straightforward. I told how the French lizard having been lost for twenty-six days in May of the following year, the Spaniard refused all food; and how, his companion having been found again, he went at once to catching flies. I praised their good understanding with one another, and their fellowship, which, however, did not extend to self-denial; and I related with great pleasure how, by forbearance and kind attention, I finally established excellent relations between myself and the Spaniard, while only a few delicate attentions were needed to gain the heart of the French lizard from the very first.
I concluded that the animals which we are accustomed to regard as in the lowest degree of intelligence among vertebrates, and which we are apt to suppose are all cast in a common mold, offer notable differences in character and docility. Yet, since those which are under consideration here are adults, they have necessarily each received the share of force and cunning which was indispensable to enable them to come safely out of the struggle for existence. Whence do their peculiar qualities come, and what use do they make of them? In wild animals, whose mode of life presupposes a well-determined combination of native qualities which age can only develop and strengthen, should not differences tend to disappear?
What I have to relate now is not less curious than my former story. I do not even know — although like observations ought to be made on domestic animals like the dog — that the bearing of them as traits of animal psychology has been brought out. My Spaniard is certainly a lizard apart. He is somebody.
But before going into individual details, I will add the final to the incidents which I have already given concerning my lizards. I have had them three years, and they have kept in admirable health. They have not hibernated, for the house has been kept warmed all the time, and their cage has been near a register. They have therefore been all the time wide-awake and very active. From this we conclude that hibernation is not organic with them like the rest of plants, and that it is a consecutive of cold weather, which causes besides the disappearance of the in- sects on which they feed.
Their food, therefore, does not necessarily consist of living prey. They eat with the same appetite the remains of beetles, such as the skeletons of night borers, and all decayed or dried chrysalides. Last year, the cabbage butterfly being extremely abundant, I col- lected a stock of chrysalides which they devoured to the last one. They always refused raw and bloody meat. ISTevertheless, when they were forced to swallow it, which was not easy, they di- gested it.
They are said to be fond of grapes, and in vine-growing coun- tries, I was told, hunt for the fruit. But with me they never wanted grapes, not even the southern variety or the dried raisin.
On the other hand, they are fond of dates, and attacked them with avidity the first time they saw them. I made them up some balls of dates as large as a good-sized grape, of which they were able to swallow three or four one after another I received other ocellated lizards last year, and they all liked dates, one of them to my surprise gulping down a whole one in a wink. It agreed with him perfectly, his digestive powers, as I took pains to observe, proving adequate to dispose of the stone in a proper manner, al- though my friends feared that it would be caught in the sinuosi- ties of the intestine, with perhaps fatal effects. It seems that this animal estimated rightly the capacity of his digestive apparatus. The preceding curious feature in the present case is that all the lizards at once recognized an eatable fruit in the date, although they had never seen or tasted dates or anything like them. They may have eaten figs at home, but they refused dried figs.
All my lizards lived, I might say, in freedom. During our summers in the country, they had a large room with latticed windows, with sunshine on three sides. They had stones and boxes of every sort, and for a gymnasium convenient scaffoldings furnished with rags in which they climbed, hid, and chased one another with evident amusement.
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At Li^ge they live in my office. They usually keep in their cage, wliere there are also rags. When the sun is shining, they come out and scramble among the books or over me. The Span- iard looks at me when I am writing. They run over my person, hide in my clothes ; and one day last year I had so completely forgotten them that I went out to deliver my lecture with my two animals on my back. I perceived them after I had been some time on the lecture stand, and was in mortal terror during the rest of the lesson, lest they might take a notion to perform their untimely and undignified gambols.
As my children, too, are fond of playing with them, they are always under observation. My articles have given them a Euro- pean reputation. M. Tarde, the eminent sociologist and crimi- nalogist, passed eight days with them. M. Forel, the celebrated student of ants, found them after a few days as interesting as his ants. They were intimate with a learned English psychologist, M. Waller, and his wife, and had the honor of being presented to eminent physiologists like M. Morat and great poets like M. Jean Aicond. They have even been invited into society and caressed by beautiful and noble ladies, whom they conquered by the grace of their motions and the beauty of their dress. Thus they have acquired gentle manners and are in safe and agreeable relations. Man inspires no fear in them, and they play indiscriminately with all visitors who encourage their familiarities.
When they play in the light and make turns in their gymna- sium, going out, re-entering, putting their noses against the win- dow, turning their pretty heads, or flattening their backs in the sun so as to receive more of its rays, they really present a charm- ing spectacle ; and I think, not without a shade of sadness, how nearly some countries would resemble a terrestrial paradise if man, instead of making himself the terror of everything living, would become its protector and friend.
Ail my lizards but one come at my call, whistle, snapping of the thumb, or jpsitt, to take flour worms or dates. They know where their larder is. When we go to the worm keg, they divine what it means, and are all on the alert, manifesting their expec- tation with unequivocal signs. The Spaniard, at first the most savage and stupid, became the most familiar and apparently on the best understanding. Not only was he not afraid of being taken, but he seemed to find pleasure in it, and suffered himself to be caressed for hours without giving a sign of weariness. He liked to be scratched under the jaw, however roughly.
The story of the way this transformation from wild to gentle was brought about is long but suggestive. MM. Sabbatier and Robert, of Montpellier, and M. Tarde had promised to send me ocellated lizards, but had not been able to fulfill their promise.
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I was regretting it, when M. Winssinger, an engineer of Brussels, put me in communication with one of his friends, M. H. Dineur, Director of the Mines of Fillols, near Prades. He sent me an ocellated lizard on the 1st of October, 1891. This lizard died by being inadvertently smothered, at the end of March in the next year. The autopsy disclosed that it was a female ; it weighed only fifty-six grammes, while the Spanish lizard weighed more than one hundred and thirty grammes, and the one from the Tarn more than ninety grammes. The Spanish lizard was a male.
It possibly came to pass that the young female disturbed the harmony between the Spanish and the French lizards, for I ob- served that they no longer lived on a footing of complete in- timacy. I observed at first only scoldings between them, but these were succeeded by bitings. In the beginning the quarrels were transient, but they became more and more frequent, and the acts of hostility were graver — the Spanish lizard, presuming on his strength, pursuing his rival, driving him out of corners, biting him, and at last rendering his existence so miserable that I was obliged to separate them. After the tragic death of the lizard of Prades, I hoped there would be a reconciliation, but there was none. The French lizard, indeed, made several attempts to estab- lish peace, but the Spaniard sprang upon him furiously as soon as he perceived him and made him scamper his fastest.
M. Dineur sent me other consignments of lizards, six in all. One very small one escaped into the field ; another died a little while after its arrival. It was a very fine animal, but it had sharply bitten a workman who picked it up, and the stupid and cruel brute took his revenge upon it by making it bite a bar of red-hot iron. Its mouth was all a sore when I received it, and it survived its horrible burning only a few days.
Among the four new lizards that were left me was one for- midable one, which, although it lost most of its tail when it was captured, still weighed nearly two hundred grammes. They very soon became familiar, except one, which, while it would eat from the hand, persisted in running away if one tried to pick it up, and bite when it was captured. The Spanish lizard received them hospitably, but if I put the French animal among them he would immediately recognize him and chase him.
But after some weeks of peaceful living together, the Span- ish lizard began to tyrannize over his new companions too, the largest at first and then the smaller ones. He is a decided teaser and a bad bedfellow. Nothing can be more curious then the tac- tics he employs to cut off their retreat. He turns himself cross- wise, in such a way as to bar their passage. Then, when he has driven them into a corner, he lifts up his paws, swells out his neck, puts down his head, darts his great open mouth at them.
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and bites them on the head, tlie flanks, seldom on the paws or tail. The large lizard in particular was the favorite object of his attacks. The good-humored animal paid no attention to this, till we were on the point of asking ourselves whether ho did not re- gard these bitings as marks of friendship. This lasted some two or three months. But one fine day — we were present at the scene — the large lizard became impatient. He seized the Spaniard with his formidable mouth, shook it, let it go, and then set in chase of it. The other ran off as fast as he could, giving all the signs of terror. After this the large lizard became quiet, and even seemed to have forgotten the matter.
The Spaniard took no notice of the generosity of its antagonist. Only becoming more prudent, it devised other tactics. Pretend- ing indifference, it approached the Hercules slyly and a step at a time, and when it was near enough to him struck him with its jaw and ran away. Finally, the large lizard concluded that the Spaniard was too provoking; he sprang upon it anew, caught it, and gave it a forcible blow. After that the Spaniard re- garded itself as beaten, always fled at the approach of the large one, and let him alone. After that, too, it prepared to make its attacks and bitings on the smaller ones. Its bad character be- came the cause of its being given a privileged position. It was put in the cage only while the others were allowed to be at large. If it sees us playing with them, it comes and goes into its cage like a troubled soul, and vents its anger ujjon the trellis. It is exceedingly jealous, and its jealousy blinds it so much that it could not refrain from still taking its satisfaction out of the large one if it saw him running over me. The rest of the time it played freely, and did not abuse its liberty in any other way. It usually perches on its cage by the side of the chest furnished with rags, which serves as its sleeping-room. Toward three or four o'clock in the afternoon it regularly goes to bed, and comes from it habitually toward sunrise. Is not this a singular history ; and does it not show that animals have passions, preferences, and antipathies, differences of character and changing moods which we have thought exclusively applied to men ?
We now come to traits of intelligence. The cover of the Spanish lizard's chest slides. If it is pushed so as to leave a crack not largo enough for him to go through, he works perseveringly, pushing his head into it till he has made it large enough. If the opening is too small for that, he scratches at it and makes a great noise with his paws, for the purpose, apparently, of making him- self heard. In the same way sparrows knock on the windows of houses whore they are accustomed to being fed. This reminds me of a story of a sparrow.
Several years ago I tamed one in the country. It was free in the
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garden and came at my call. If I did not call, it came all the same. As I was accustomed to liave hemp seed in my mouth, it would peck at me, picking my beard and mustache furiously till I had satisfied its appetite. It was satisfied that it had tamed me and made me its slave. My lizard is nearly in the same condition. It does not molest me, but when I take the box of worms it rises and snaps them from my hand and even from the box. It is well persuaded that man is the friend of the lizard. It has a delicate ear. When it is called from the end of the room, it turns its head to the right and the left, as if to get its bearings and find the direction whence the sound comes. It can hear the walk of an insect and a worm crawling on the ground. Its vision is likewise good, and it recognizes a meal-worm from a considerable distance.
The other lizards like their cage ; and toward three or four o'clock in the afternoon they will all, if they are, for example, on the table, start to come down, using the chains to help their descent to the ground, and then climbing back into their abode and hiding by choice in their rag houses.
The Spaniard, notwithstanding his jealous, vindictive, and vengeful character, is more petted than the others, because we have him constantly in hand, and he is the easiest to take up and exhibit. For this reason too he is best at the little tricks we teach them. But, in view of the stupidity he manifested for several months, there is no doubt that the others, which, as I have said, with one exception became gentle and trustful in two or three days, if they had been the objects of the same careful attention, would have given still more marked proofs of capacity for edu- cation. If I turn the Spaniard on his back and make a sign to him with my finger, he will remain there for some time, but not without showing some impatience and raising his head. The animal is obedient to force, however mildly it may be exercised, but such obedience is a sign of reasoning.
It can not be denied that all its ways have a perceptible re- semblance to those of the dog, particularly if we take into the ac- count its i^overty of means of expression. I saw in the London Zoological Gardens an Australian lizard, high on its legs, with the bearing and head of a greyhound, and very pleasant large eyes. I have forgotten its name. It impressed me as being easy to edu- cate, so far as I could judge of lizards by the face. And what might we not get from large lizards if we should succeed in form- ing a domesticated race ? We should not forget that my animals were captured adult. The conclusion of my long story is that the enormous intellectual differences which we usually assume as be- tween reptiles and the highest mammals probaljl)^ do not exist, and consequently that there is in the brain of reptiles sufficient avail-
�� � available matter to permit them to adjust themselves to a certain degree of domesticity or to sociability; and it is the social state which, other things being equal, is the highest product of animal as well as of human intelligence. — Translated for The Popular Science Monthly from the Revue Scientifique.