SRAC Publication No. 231

SouthernRegionalAquacultureCenter

May 1993

Alligator Production

Breeding and Egg Incubation

Michael P. Masser*

Alligator farming requires specificculture techniques and specializedknowledge on the part of the pro-ducer. The commercial produc-tion of alligators can be dividedinto 3 phases:

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management of adult alligators

egg collection, incubation, andhatching

grow-out of juvenile alligatorsto market size

Louisiana, Florida and Texaseggs and/or hatchlings maybetaken from the wild under specialpermit regulations. In all otherstates it is illegal to take eggs orhatchlings from the wild (in 1993).Therefore, prospective alligatorfarmers must either purchase eggsor hatchlings from other produc-ers or produce their own. Louisi-ana law makes it illegal to sellalligator eggs outside of Louisiana.Hatchlings can be purchased fromexisting farms or hatcheries in Lou-isiana, Florida and Texas. Theprice of hatchlings changes yearlydue to the laws of supply and de-mand. In 1990 hatchlings sold for$30 each or more. In 1992 theprice had fallen to about $20 each,largely due to the low marketprice for hides.

This publication addresses thecare of adult alligators, their breed-ing, and the collection, incubationand hatching of alligator eggs. Forinformation on grow-out of juve-nile alligators to market size seeSRAC Publication No. 232, Alligator Production: Grow-out and Har-vest.

difficult. Exact environmental, so-cial and dietary needs of adult alli-gators are poorly understood. Thefollowing discussion is based onthe limited amount of researchavailable and from personal com-munications and observationswith both researchers and commer-cial producers.

Management of breedingAdult alligators that have beenreared entirely in captivity/con-

alligators finement behave very differentlyfrom wild stock. Farm-raised alli-

Maintaining adult alligators and gators accept confinement andachieving successful and consis- crowding as adults much bettertent reproduction is extremely

* Extension Fisheries Specialist AuburnUniversity, Alabama Adult alligators feed on red meat in a pond environment.

than those captured from the wild.Also, adult alligators that havebeen raised together tend to de-velop a social structure, and adaptquicker and breed more consis-tently than animals lacking any es-tablished social structure.Inbreeding can be eliminated byobtaining males and females fromdifferent clutches. However, itmay not be possible to obtainadults using the above criteria.

If adequate numbers of adults can-not be purchased, then the beststrategy may be to select futurebrood stock from your own younganimals or purchase young fromanother producer. Try to selectfast-growing individuals. Captivealligators raised in temperature-controlled environments for threeyears reach sexual maturity at 5 to6 years of age compared to the 9 ormore years that it takes in the wild.

Pen design for adultalligators

Pens for adult alligators need tobe one to two acres in size. Largerpens have been used but can pre-sent problems if alligators haveto be captured. Pens must be care-fully fenced to prevent their es-cape. Some general recommenda-tions for fence design include:

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heavy-duty, woven, rust-resis-tant wire,

wire should be a minimum of 6feet high and buried in theground to a depth of 1 foot,

mesh size should not exceed 2 x4 inches,

a 1 x 6-inch treated boardshould be attached to the inte-rior base of the fence,

fence posts should be spaced on8-foot centers,

fences should have roundedcorners (avoid 90° comers asthey encourage climbing andpiling-up of the alligators),

gates must be equal in height tothe rest of the fence and of com-parable fencing material,

8. gate frames must be heavy-duty, attached by at least 2hinges, and secured by at least 2latches along the opening.

Remember, alligators can climb,are very strong, and will probablytry to escape. Improper construc-tion of holding pens which allowsthem to escape is illegal in moststates. Check with your stategame and fish agency for specificguidelines.

Breeding pen design, particularlythe land to water ratio and configu-ration, is very important. Landarea to water area within the penshould be approximately 3:1.Shape of the pond(s) needs tomaximize shoreline. Presentthinking suggests that an ‘M’, ‘S’,‘W’, ‘Z’ or similar shape is best, al-though other pen designs havebeen used. One experienced pro-ducer observed that male alliga-tors fight less during the breedingseason if they cannot see eachother in the pond, thus the reasonfor the shape of the ponds. Thepond shoreline should be no closerthan 75 to 100 feet from the fence.

Water depth of at least 6 feet mustbe maintained during the breedingseason, which could require awater source (i.e., well, reservoirpond, etc.) When possible, pondsshould also be constructed withdrains so that water can be re-moved if the animals need to becaptured.

Dense vegetation around the pondis needed to provide cover, shadeand nesting material. The naturalinvasion of wetland plants is suffi-cient for cover in many areas.However, many producers feelthat invading vegetation is not op-timal for nesting purposes and pre-fer to plant alternative types ofvegetation. Brush and cane typevegetation (because of its coarsenature) should be discouraged asnesting material because it canpuncture and kill eggs as they arebeing laid into the nest. In gen-eral, vegetation for nesting mate-rial needs to be a rank growinggrass (i.e., tall, deep grass, 24 to 30inches in height) that will hold

sufficient moisture, not desiccateduring incubation, and not rot tooquickly. Tall fescue maybe agood candidate for vegetativecover in much of the South. Manyproducers add bales of hay to thebreeding pens in June to supple-ment natural vegetation for nestbuilding.

Shade is important to preventoverheating during the summer.Alligators will burrow into thepond banks if adequate shade isnot provided. Burrowing can bereduced by building shade awn-ings in the pens.

Stocking density of adult alligators(from farm-raised stock) should bebetween 10 to 20 per acre. Someproducers have been successful atdensities as high as 50 per acre;others maintain densities at 6 to 8per acre. Adults between 6 and 20years old are usually reliablebreeders, females 8 to 10 years oldare the most consistent breeders.Female to male ratio should be ap-proximately 3 to 1 (but less than4:1).

Each pen should have several feed-ing stations to keep the alligatorsspread out during feedings. Feed-ing stations should be establishednear basking areas where alliga-tors sun themselves or along pathson the shoreline of the pond. Feed-ing should begin each springwhen temperatures rise above700F (usually March or April).Feed 4 to 7 percent of body weightper week (7 percent throughoutthe summer months). Adults areusually fed only once per week.Early fall feeding appears to beparticularly important so that thefemales are in good condition foregg development. Adults do notneed to be fed during the late falland winter. It is important thatadult alligators are not overfed;they should be in trim body condi-tion, not fat!

Adult breeders should be dis-turbed as little as possible fromFebruary through August duringegg maturation, courting and nest-ing. Activities such as moving ani-mals or pond maintenance should

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be performed between Septemberand January.

Alligators are extremely shy ani-mals and are easily stressed.Stress reduces growth rates, fertil-ity rates and probably predisposesthe animals to disease and infertil-ity. Farms should be located inareas where outside disturbancecan be minimized. Producers musttry to limit all stressful contactwith people and other animals(see section on stress in SRAC Pub-lication No. 232, Alligator Produc-tion: Grow-out and Harvest).

Courtship and breeding

Courtship and breeding activity isextremely important. Alligators ap-pear to develop a social structurewithin a group. Wild alligatorswhich are captured and penned

can be very aggressive towardeach other during the breeding sea-son. Wild males have been knownto kill rival males during the breed-ing season, and wild females willkill, or not breed with, unaccept-able males. Alligators raised incaptivity are less territorial and ag-gressive towards each other, par-ticularly if they have been pennedtogether before they are 3 yearsold.

Courtship and breeding occur be-tween April and July dependingon temperature/weather condi-tions. Courtship is a time ofheightened activity by both sexes.This activity includes vigorousswimming and bellowing. Bellow-ing is the most common activity as-sociated with courtship, althoughlimited bellowing can occur atother times. Most courtship and

mating occurs just after sunrise indeep water, and repeated copula-tion is commonly observed. Themating sequence from precopula-tory behavior through first copula-tion takes approximately 45minutes.

Nest building and egg layingoccur at night. The nest is builtfrom natural vegetation (e.g.,broomsedge, bullwhip, cutgrass,wiregrass and available annuals),hay (if provided), and soil. Nestsare built into a round, mound-typestructure. A female may start sev-eral nests before a single nest issuccessfully completed. Eggs aredeposited at the top of the moundand then sink to the center form-ing layers with vegetation. Fi-nally, the eggs are covered withapproximately one foot of vegeta-tion. All nesting activity usuallyoccurs within a two week period.

T0 T1 T3 T5

T7 B7 T30 T52

Figure 1. Opaque banding of alligator eggs from day laid through day 52 of incubation (Ferguson 1981).T = top view; B = bottom view; numbers= days of incubation.

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Typical alligator nest in the wild.

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Baby alligators hatching from eggs.

The female guards and protectsthe nest but predation from rac-coons and other animals is com-mon. Nests can also be destroyedby other females trying to buildnests if pen density is too high orif vegetation for nest building isscarce. Farm-raised females havebeen known to lay eggs in thesame nest, again demonstratingthe breakdown of territoriality thatis common to wild alligators.

Nesting success in captive alliga-tors has been highly variable.Wild versus farm-raised origin,pen design, density, developmentof a social structure within thegroup, and diet all impact on nest-ing success. Nesting rates foradult females in the wild averagearound 60 to 70 percent wherehabitat and environmental condi-tions are excellent. Nesting ratesin captivity are usually muchlower, depending on the manage-ment skill of the farmer. If farm-raised animals are selected andgrouped together at an early age,pens are constructed properly, sexratios are near three females toeach male, densities are around 20alligators per acre or less, andstress is eliminated, then diet be-comes the most important factorin reproductive success (see sec-tion on diets). A few good manag-ers have achieved nesting rates of70 percent of the adult femalesnesting each year.

Clutch size varies with age andcondition of the female. Large andolder females generally lay moreeggs. Clutch size should average35 to 40 eggs (range 2 to 58). Eggfertility can vary from 70 to 95 per-cent. Embryo survival can alsovary from 70 to 95 percent. Hatch-ing rate varies from 50 to 90 per-cent. Egg fertility, embryosurvival, and hatching rate of eggstaken from the wild and incubatedartificially are 95, 95, and 90 per-cent, respectively. Captive repro-duction can and should approachthese values.

Reproductive success of captivealligators has been the most diffi-cult problem for producers to over-come and is probably the greatest

obstacle to face prospective breed-ers.

Egg collection

The method and timing of egg col-lection is very important. Alliga-tor embryos are very sensitive tohandling (mechanical injury) from7 to 28 days after they are laid.Many embryos will die if handledduring this period. Current recom-mendations are either to collecteggs within the first week or waituntil the fourth week of natural in-cubation. Collecting eggs withinthe first 24 hours after being laidhas several advantages:

Eggs are not easily damaged be-cause the embryo is not yet at-tached to the shell.

Egg collection allows the farmerto separate good eggs from in-fertile or dead eggs.

Eggs that were laid upright canbe repositioned.

It eliminates losses caused bypredation and/or bad weather.

It eliminates losses in breedingpens when more than one fe- -

male tries to lay eggs in thesame nest.

After 4 weeks of incubation theembryo has developed enough toresist most damage from handling.

Most alligator eggs cannot beturned or repositioned when takenfrom the nest (unlike bird eggs).Eggs should be marked with an“X” across the top before remov-ing them from the nest so that theycan be maintained during trans-port and incubation in the sameposition as they were laid. Eggsthat are laid upright in the nest(long axis perpendicular to theground) will die unless reposi-tioned correctly (long axis parallelor laying on its side and not onend) before artificial incubation.This repositioning can only takeplace in the first few hours afternesting.

Some captive alligators will aggres-sively guard their nests. Use cau-tion collecting eggs. It is a goodidea to work with another person

while collecting eggs. If the femaleis not aggressive then do not an-tagonize her. Many times an ag-gressive animal can be chasedaway or kept at bay using a longsturdy pole.

During collection place 8 to 12inches of nesting material or grasshay (moisten several days in ad-vance) in the bottom of the collec-tion container to support the eggs.Place the marked eggs in a singlelayer in the container and in thesame position that they were inthe nest. Cover the eggs with 2 to3 inches of nesting material. Trans-port very gently!

Age of the eggs and developmen-tal progress can be observed bychanges in the opaque bandingthat occurs during incubation. Fig-ure 1 shows the sequence of band-ing associated with proper eggdevelopment.

Incubation and hatching

Artificial incubation, compared towild nesting, improves hatchingrates because of elimination of pre-dation and weather-related mortal-ity. The best hatching rates foreggs left in the wild is less than 70percent. Hatching rates for eggstaken from the wild and incubatedartificially average 90 percent orhigher.

Eggs should be transferred into in-cubation baskets and placed in anincubator (environmental cham-ber) within 3 or 4 hours after col-lection. Air circulation around theeggs during incubation is critical.Egg baskets or trays are best madefrom PVC coated 1 x 1/2 inch steelwire mesh or 1/2 inch heavy dutyplastic mesh. Top, bottom andsides of the baskets should bemade from the mesh material toenhance air circulation. Dimen-sions for egg baskets can vary (1foot x 2 feet, 2 feet x 2 feet and 2feet x 3 feet are common) butshould be 6 inches in depth to ac-commodate eggs and nesting mate-rial. Eggs must be completelysurrounded by nesting material.

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The decomposition of the nestingmaterial aides in the breakdown ofthe egg shell. Without this naturaldecomposition, hatching alligatorswill have a difficult time breakingout of the shell and some may die.Fresh, natural nesting materialcomposed mostly of grasses isbest. If natural nest material is notavailable, use grasses which havebeen soaked for about a week.Sphagnum moss can also be usedas incubation material. Producerswith captive breeders dip the eggsand incubation substrate in an anti-fungal agent like chlorhexadine di-acetate before incubation to reducepotential disease problems. Wildeggs are seldom treated before in-cubation.

Hatching baskets are set onshelves or brackets about 3 inchesabove the water in an incubator.The temperature, humidity andwater level are controlled in the in-cubator. Figure 2 is a constructiondiagram of a small environmentalchamber developed at the Rocke-feller Wildlife Refuge at GrandChenier, LA. The cost to build thisenvironmental chamber was ap-proximately $5,000. Other produc-ers use separate buildings withtemperature and humidity controlor small tanks housed inside a tem-perature-controlled grow-outbuilding. Relative humidityshould be kept above 90 percentwithin the chamber, and incuba-

tion media should be moistenedwith warm water as necessary tomaintain dampness.

Incubation temperature is criticalto survival and proper develop-ment. It also determines the sex ofthe hatchlings. Temperatures of86°F and below produce all fe-males while temperatures of 91°Fand above produce all males.Temperatures much above 91° orbelow 86°F, however, cause abnor-mal development usually result-ing in high mortality. Both sexesare produced at temperatures be-tween 86°F and 91°F. The criticaltemperature period for sex deter-mination is around 20 to 35 daysafter the eggs are laid. Most pro-ducers now incubate eggs at 88° to90°F. This produces a mixed sexpopulation with good survivaland growth.

Hatchling alligators make peepingor chirping sounds after hatching.When 10 to 15 percent of theclutch has hatched many produc-ers carefully open unhatched eggs.Eggs are cracked and opened atone end to free the baby alligator,but care must be taken not to de-tach or damage the umbilicalcord. If the umbilical cord is bro-ken the hatchling is likely to bleedto death or develop an infection.Hatchlings are retained in theirhatching baskets for 24 hours toallow the shell and umbilical cordto separate naturally. After 24

hours the hatchlings are removedfrom the egg baskets, sorted intouniform size groups, and movedinto environmentally controlledgrow-out facilities. Closely sizingthe alligators is very important.Smaller, weaker individuals willnot be able to compete with theirlarger siblings.

A few producers specialize in pro-ducing hatchlings for resale toother farms. Most hatchlings arenot sold until they are activelyfeeding. Once they are activelyfeeding they are ready to bemoved to grow-out facilities.

For information on the grow-outof alligators see SRAC PublicationNo. 232, Alligator Production: Grow-out and Harvest.

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The work reported in this publication was supported in part by the Southern Regional Aquaculture Center through Grant No. 89-38500-4516 from the UnitedStates Department of Agriculture.