1901-artificial incubation of alligator eggs - reese

8/2/2019 1901-Artificial Incubation of Alligator Eggs - REESE

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Artificial Incubation of Alligator EggsAuthor(s): Albert M. Reese

Reviewed work(s):Source: The American Naturalist, Vol. 35, No. 411 (Mar., 1901), pp. 193-195Published by: The University of Chicago Press for The American Society of NaturalistsStable URL: http://www.jstor.org/stable/2454333 .

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ARTIFICIAL INCUBATION OF ALLIGATOR EGGS.ALBERT MI. REESE.

THE writer eceived, bout the first fAugust, 1900, a lot ofalligator eggs from southern Georgia, and in order to geta series of embryos at different tages of development, twas necessary to find some means of incubatingthe eggsartificially.As is well known,the Florida alligator lays hereggs, aboutthirtyn number, n a so-called nest, which she constructsofsticks, leaves, earth,etc., on the banks of the pondor streamin which she lives. The eggs are laid in the cavity of thisnest, and are carefully overedand allowed to incubateby theheat of the sun. When the young alligators are about readyto hatch, theymake a curious squeaking noise,which attractsthe mother'sattention, nd she uncoversthe eggs so thattheyoung alligators mav not be smothered n the nest aftertheyescape from he eggs.The lot of eggs above mentioned was sent by expressfromGeorgia to Baltimore,and arrived in good condition,beingpacked in damp leaves and luinius, probablyfrom the nativenest. Several of the eggs were at once opened, and werefound to contain living embryos in an advanced state ofdevelopment.As the incubator which is ordinarilyused for chick eggswvasnot in operation, n attemptwas made to imitatenature,and the eggs were put into a large bucketof the loosely packedluimiis in which theyhad been received. Two thermometerswere thrust into the ibmitts, one deep clown to the bottom ofthe bucket, and the other near the surface. The whole artifi-cial nest was covered with thick cloths and put in the sun towarm. Before sunset the nest was brought nto a small roomwhichcould be tightly losed to prevent any verydecided fallin temperature. The weather was intenselyhot at thistime,193


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194 THE AMERICAN .1VA URALIST. [VOL. XXXV .so that no difficulty as experienced in keeping the eggsat a sufficientlyigh temperature. By very careful watchingthe temperature of the egos was kept fairly constant, theextremes being 320 C. and 40? C. In spite of this care, theembryoswithin the eggs were kept alive only a little over oneweek, and whether hey were killed by too great heat, too littleair, or too great variation in temperature, t was not easyto decide. It would seem that in nature the eggs must besubjected to a much greaterrange of temperature than theywere in this case, so it seemed probable that it was lack of airthat caused the death of the embryos.Towards the end of August a second lot of eggs wasreceived, but the contained embryoswere in such an advancedstate of development that most of the eg-gswere opened andthe young alligators preserved for anatomical study. WVhenthe shells were opened the young alligators would wriggle out,snapping their little toothless jaws and blinkingtheir eyes,although there was still a mass of unabsorbed yolk protrudingthrough he abdominal wall as large as a pigeon's egg.A few of these eggs were packed in a small box of damphumiSs, to prevent drying, nd were kept in an incubatorat atemperature f 370 C. On opening the incubator couple ofweeks later, curious squeaking sounds wereheard comingfromthe inside of the eggs, the sounds which, n nature,tell themother hatheryoungare about readyto hatch and shouldbehelped out of the mass of earthand leaves in which theyareburied. These sounds are audible at a distance of fifteenyardsormore, o thatevenwhenthe eggs are buried n the nestthe parent s probably ble to hear the call of heryoung. Thenext day afterthe first ound was heard one of the alligatorsbroke out of its shell, and a couple of days later two morehatched; the rest of the eggs provedto be infertile.During the act of hatching, heyoung alligatorswouldsnapat the fingers,or any small object, quite savagely; but afterfinally scaping fromthe egg theycould not be inducedto doso. The umbilical scar persistedfor some timeafterhatching,but gradually disappeared. The alligator is about 20 cm. inlength when hatched, and that an animal of its bulk should


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No. 411.3 INVCUBATIOAN OF ALLIUATOR EGGS. 195have been contained in so small an egg is quite astonishing.These three artificially atched alligators are now living, inapparent good health, n a glass-coveredbox in the laboratory.They are fed,about once a week, on small bits of raw meatwhich are thrown nto the shallow pan of water in their box.It is probable that had the firstot of eggs been treatedas wasthe second lot, the desired stages of developmentmighthavebeen obtained.

JOHNS HOPKINS UNIVERSITY.

1901-artificial incubation of alligator eggs - reese

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