Bull. Chicago Herp. Soc. 42(3): 41-43, 2007 Reproduction of the Atlantic Bushmaster

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Bull.  Chicago Herp.  Soc.  42(3):41-43,  2007

Reproduction of the Atlantic Bushmaster (Lachesis muta rhombeata) for the First Time in Captivity

Rodrigo C.  G.  de Souza

Serra Grande Grande Center for Lachesis m uta Breeding

Itacaré/ Bahia


lachesisbrasil@hotmail. com


Captive reproduction of Lachesis muta muta was achieved

in the ’80s at the Dallas Zoo (Boyer et al., 1989).  Ripa (1994)

published an account of the reproduction of the Central Ameri-

can species Lachesis stenophrys and Lachesis melanocephala

In this paper we present our experience in the reproduction of

Atlantic bushmasters in captivity for the first time, involving

parental (male and female) DNA from two (maybe three)

different couples.

Materials and Methods

It took us five years of environmental education to avoid

unnecessary killings and to form the groups (de Souza, 2006). 

As Ripa (2002) points out about our work:  “de Souza’s Project

Lachesis in the Atlantic Forest of Brazil, is a real bushmaster

‘farm’ where nuisance bushmasters colliding with encroaching

development are housed in outdoor enclosures separated only

by screen barriers from natural rainforest surrounding

them. . . .  De Souza has constructed artificial burrows based

on paca burrows and the snakes’ inhabit these exactly as in

nature.  The snakes experience the normal rainfall, humidity

and temperature gradients typical to the area.”

Our first step was to select healthy adults weighing over 4

kg to ensure overall (not only sexual) maturity and good gen-

eral condition, with some extra energy to spare.  All of them

were probed, dewormed and received a special diet in the

“intensive” system, or individual boxes, prior to their introduc-

tion into one of four 2:2 groups, which occurred by the end of

August 2006.  To reduce and, maybe avoid altogether the

possibility of loss of libido or sex drive, a problem already

observed in colonies kept in small cages, the animals were

communally kept for six months in large enclosures (up to 40

m  [430 sq ft]), built indoors in what we call “semi-intensive”


system or outdoors in what we call the “extensive” system,

both in prime Lachesis muta rhombeata territory, the Atlantic


In late September 2006, during a series of cold fronts and

thunderstorms, two of the four groups displayed indirect signs

of sexual activity (male combat):  destruction of plants, large

water bowls flipped over, uncoiled animals seen “side by side”

by one of the keepers.  On 14 December, we performed an egg

search in these two enclosures and found one clutch in each

group, totaling 18 eggs.   The fact that some of them could not

be separated from their clusters suggests egg-laying a few days

prior to the discovery.

In our region, cold fronts usually occur in September/

October, bringing sudden temperature drops and rising humid-

ity levels, a condition that Boyer et al. (1989) showed to trigger

hormonal response in female bushmasters.  If mating takes

place during these months, egg-laying will happen in the “dry”

season (January through March) when flooding is less likely to

occur.  In our experience, this apparently logical and evolution-

oriented calendar seems to be fiction,  and there’s no such thing

as a “breeding season” for bushmasters in the wild.  We

recorded actual mating again on 4 January 2007, during an

unexpected cold front.   Egg-laying should take place some 100

days on, coinciding with the beginning of the wet season.

The “no breeding season” idea is also supported by the fact

that in any given 12-month period,  we detect no pattern in the

size, thus age, of the animals we encounter, which vary from a

couple of months old, up to “teens” and young adults.

Based on previous experience, our main concern was to

keep insects in general and, particularly, a very small fly

(about one-quarter the size of a typical Drosophila), endemic in

our region, from getting to the eggs.  The problem was that,

Eggs found in an outdoor enclosure

Eggs found in the indoor enclosure


while we had to guarantee that the protection would be tight

enough to keep these flies away, normal egg metabolism had to

be preserved.  Since we had no information regarding gas

exchange of the eggs, we decided to conduct a simple experi-

ment to test if our protection scheme (more below) would allow 

normal metabolism of the eggs.  The experiment was based on

the reasonable assumption that the metabolic requirement of an

egg is less than that of a small gecko (Hemidactylus mabouia). 

We placed a 4" specimen of this gecko under the same condi-

tions as the eggs and were able to keep it alive and well for two

weeks without any air renewal.  Just to be safe, we decided to

ventilate each bowl every third day and inserted insulin needles

through the plastic film covering the glass bowls to serve as

vents, assuring free gas exchange without compromising the

protection against the tiny flies (circle in the picture below).

The chosen substrate was vermiculite, mixed 1:1 by weight

with sterilized water.  This vermiculite was kept in an oven at

300EC (572EF) for 3 hours and vacuum packed until needed, a

month later.  Fungi were not a problem.  Since we are experi-

encing one of the hottest summers in recorded history, every 10

to 15 days each medium received 10 ml of sterile water (the

same normally used in hospitals).  The temperature in the

Atlantic rainforest, where the vivaria and the eggs were kept,

was naturally always between 25 and 28EC (77


82EF) and the

humidity levels were always between 80 and 95%.

We decided to add some extra protection, an adapted 200-l

(53-gallon) aquarium in which we placed the sealed glass bowls

with the eggs when we found a rice rat (Oryzomys sp, a bush-

master’s favorite) in the incubating room.  These little guys are

known to eat anything,  eggs included.

The decision to follow common sense and avoid “placing all

eggs in the same basket,” dividing them in several bowls,

turned out to be very important,  because on the 50th day of

incubation,  one of the handlers in charge of the ventilation of

the bowls, left one of them uncovered for 24 hours and, within

a few days, the eggs shriveled up.  Their shells became leath-

ery and changed color, from white to a greenish yellow.  The

picture below shows these eggs with a window cut off, allow-

ing us to clearly see the fetuses, with their loreal pits clearly

formed already (arrows).

Out of 18 eggs (78


82 g each, 4 samples) from two differ-

ent groups, one atresic egg was lost in the fourth day, two lost

to flies in the 50th day and 15 babies (39


61 g, total length 43


49 cm) are doing fine.  Hatching between 74


79 days at 75EF

(25.4EC) average under 80


99% humidity levels.  We credit

the good success ratio to the cool conditions.  The Atlantic

rainforest, natural Lachesis territory, determined these atmo-

spheric parameters; no electricity or technology was involved.


Manipulation of the eggs when they start “pipping” or when

the snout starts to protude may lead to a twisting of the umbili-

cal cord and nutritional deficit.  Sometimes the neonate will

take as long as 5 days to leave the egg and attempts to “help”

or even to take good photographs may lead to harmful motion.


Following in the footsteps of Boyer and Ripa, we have

achieved an important step towards the preservation of the highly

endangered Atlantic bushmaster.  Our observations lead us to

conclude that there is no such thing as a “breeding season” for

bushmasters in the wild.   Every cold front is a potential breed-

ing season for these rare, reclusive, demanding and highly 

specialized snakes, already faced with the destruction of 93%

of their Atlantic rainforest habitat.  For the second time, we

observed apparent male/female guarding of eggs, behavior yet

to be confirmed by further observation.


We would like to express our gratitude to Paulo de Tarso,

YONIC Organization Director for the friendship and finantial

support; to Dean Ripa (Cape Fear Serpentarium), Ruston

Hartdegen (Dallas Zoo) and Rob Carmichael (Elawa Wildlife

Discovery Center) for their guidance and also to João Luis

Cardoso, Butantan Institute, for his trust.

Literature Cited

Boyer, D. M., L. A. Mitchell, and J. B. Murphy.  1989.  Reproduction and husbandry of the Bushmaster Lachesis m. muta at the Dallas

Zoo.  Int’l Zoo Yearbook 28:190-194.

de Souza, R. C. G.  2006.  Concerning Lachesis and capoeira.  Bull. Chicago Herp. Soc. 41(4):65-68.

Ripa, D.   1994.  The reproduction of the Central American bushmasters (Lachesis muta stenophrys) and the blackheaded bushmasters


Lachesis muta melanocephala) for the first time in captivity. Bulletin of the Chicago Herpetological Society, Vol 29, No.4.


.    2002.  The bushmasters (Genus Lachesis Daudin 1803):  Morphology in evolution and behavior [CD-ROM].  Wilmington,

N. Carolina: Cape Fear Serpentarium.

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