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62
to water still might be necessary to prevent dehydration/dessication - especially
in the case of juveniles.
Exploration of the winter den by crawling through its tunnels, reveal€d it to
consist ;f a circular main lunnel tnclosing an a'ea approximately 6-8 m !n
diameter (Figure ?). Three side lunnels branched from the main tunnel, one of
which \^/as too small in diameter to be explored. The den system included two
main chambersi (1) s smaller chamber of a little less than 1 0 m in diameter'
where the juveniles were seen' and (2) a larger chamber measuring- I'5-2'0m in
diameter and about 1.0m in height. The larger chamber also contained a small
amount of pine litter, but it could not be determined \jhether this material had
any relationship to the use of this den by alljgators and no alljgators were seen 'n
th; den during its exploration on 16 July 1992. The den's system
.tunnel
represented a iotal length of about 24m' with a typical cross-section of the main
tunnel measuring 30-40 cm in height by ?0_120 cm in width' The trrnnel \ras
rcughly oval in ;hape with a flaltened boltom. Chen et al. (1990) described a
simitar strape for the cross seclion ol a tunnel from the den of a chinese aliigator
(AlliEator ;inensis), Although these authors describe the construction and usb of
etaUorate aen/tunnel systems by lhe Chinese species, until the present study'
there had been no evidence that the American species ever constructed
subterranean dens with a conparable degree of complexity.
chen et al. (1990) indicate that the size and complexity of the chinese
slligatoris burrord vary with age and sex' with those of females being more
cor;plex, Both the cross-sectional size and length of the Par Pond burrow were
within the range of sizes given by these authors for the burrows of adult chinese
alligators whoie tunnels are 33 36cm hjgh by 39-60cm wide and-whiah are
betieen 10 25m in length. l,ike the dens described by Chen et al' (1990) for the
Chinese alligator, the tar Pond den also had two entrances that were locatad in a
south-faeing thickly vegetated verticai embankment near (what had been ) the
water's edgi. The;e authors also describe small diversionary side chambers fot
young, located at the point of bifurcation of den tunnels' which ls exactly the
configuration of the chamber containing young in this sludy (Figure 7). Chen et
al. (1-990) also describe the presence of a "sleeping platlorm,'r water pool and air
holes opening to the surface in the den systems of Chinese ailjgators' While
theae w;s a ;ma hole in the roof of the easternmost side tunnel of the Par Pond
den (Figure ?), there was no evidence that thjs structure had been purposely
'fhe
constru6ted by the alligator. absence of water from the Par Pond den
prevented a determjnation of which if any portion of the .tunnel
system or
;hambers might have contained water when the den was originally construaled'
The entire Par Pond den system was generalty less than 10-20cm below the
surface of the ground considetably less than the 1.0 1.8m depth reported by
Chen et al, (1990) for the den of tbe Chinese alligator.
With the exception of the adult found in the den described above, all other
alljgators observ€d at Par Pond remained in the reservoir's open water during the
winler months. Although few visllal observations were recorded during the
winter, all of the telemetered alligators spent the colder months in locatjons that
made it extremely unlikely that any den use was taking place. AIl of the animals
were found in areas that until only recently had been covered by a depth of 6-8m
of open wat€r, anal the single observation of den use described above as \!ell as
other previous studies all indicate that when winter dens are used by alligators of
either species, they are always constmcted either at the water's edge or ln
relatively sballow water (! 2m), thus allowing the occupant easy access to the