Here
is another surprising aspect of alligator behavior. They will protect
their eggs through incubation (about 60 days), and then will protect
their hatchlings for
around two years. I've witnessed the care that
a female alligator shows while she moves among a newly-hatched pod of baby
alligators. I've faced a female alligator over her young,
and stood and
watched her with respect on more than one occasion. If her babies gave
an alarm, she--with her eyes upon me--would quietly move closer to me,
in the water. Only
if I didn't give way, or if others moved quickly or
loudly, would she actually begin her threatening behavior. If one gives
her respect, then she remains quiet, though watchful. The
picture of a
silent, strong protector of its young is not the mental image most people
would have of an alligator. Maybe these pages can alter the common perception
of alligators.
Additional
August 27 follows!
If you
were able to watch and hear the video clip with sound, then you heard 3
sounds, sort of like a cross between a chirp and a croak. Juvenile alligators
make these sounds. The following information
is drawn from:
Crocodilian
Biology and Evolution, Gordon C. Grigg, ed. Feb, 2001. The information
is in Chapter 30, written by Adam R. C. Britton. (italics
are my own conclusions/thoughts)
This
chapter deals with crocodilians in general, but seems to indicate that
the different species share similar behaviors. In any case, it's interesting.
From before they are born, young crocodilians vocalize.
They begin chirping
while
still inside the egg. This is thought to alert nearby adults (usually
the mother, since she is normally guarding the nest)
to approach the nest. Apparently, even male animals will
respond
with assistance (That is, they don't come
to eat the young.) An interesting point
is that other animals, notably predators, could also be alerted
by these sounds, and could also
respond.
If they
reach the before the adult crocodilian, then the young wouldn't
survive. Then, after they are born, the young alligators will continue
to make various sounds. What is most interesting is that there are different
sounds for
different
situations, or to give different messages. The chapter lists 5 different
calls (possibly 6). This is only one study. As with all scientific work,
it is subject to further experimentation and
verification. Calls in the
study were analyzed with sonograms, and broken down into components.
So,
many differences between the calls are quite subtle, and difficult, if
not
impossible
to detect by
humans. Some
of these signals can probably be read by context. The 5 main types
were: Hatching, Contact, Threat, Annoyance, and Distress.
1.
Hatching Calls--these were divided into "pre-hatching", and "post-hatching"
calls. The study gives differences between
calls
as occurring from milliseconds of duration, frequency, and harmonic.
The "pre-hatching" call is thought to cause the adult to open the nest,
while the "post hatching" call may help the adult locate the
newborn to
carry it to the water. There is also mention of another possible sound
that may prevent the adult from swallowing the young while it's being carried
in
the
adult's mouth. However, some of these
difference could be due to physical
conditions around the baby, such as the egg muffling the sound (I
suppose being inside an adult's mouth might cause produced sounds to be
seem different also.)
For
those who wonder, the chapter *does* mention that how the babies can produce
sounds *inside* the egg isn't known.
2.
Contact Calls-- are given from time to time, and are probably used so the
young animals can recognize their group. That is, this call helps keep
the pod together. Sometimes one baby approaching
another will make one
of these sounds. Sometimes it gets an answer. These are probably the sounds
that are being made on my video clip. These happen in non-threatening situations.
Young
crocodilians (hereafter,
just "crocs") apparently
respond to this sound favorably, sometimes
responding
to similar sounds made by other non-threatening animals, or even the adult
female.
3.
Threat calls--With the social behavior of depending on adult animals for
protection, young crocs normally will seek to escape, hide, and call for
an adult if threatened (Who
wouldn't want a dragon 10
times their size that they
could
call on for help? A baby alligator is 9 inches long. A large female is
9 feet, or 108 inches long.) . On
rare occasions, however, they will attempt to face down their
tormentor.
When doing so, they will show aggressive body postures
while
making the noise. These sounds seem to be quite different from the other
vocalizations. (From
what I can see, these are more
related to loud "hissing" noises the the
"croaking" noises.)
4.
Annoyance calls--These are high-pitched sounds that a young croc might
make after it has been grabbed. These are used in conjunction with attempts
to bite their attacker. There is no evidence
either way that shows
an adult would respond to these calls. These are generally a higher pitch
than "distress calls".
5.
Distress calls--These occur when a young croc feels threatened. They seem
to be primarily for summoning an adult. Adults other than the actual parent
may respond. These calls can also serve as a
warning to other juveniles
in the area (probably
in the same pod) that
there is trouble. One drawback of this behavior is that the caller
could be eaten before help could arrive.
Another
concept I hadn't considered was an alligator's voice changing as it grows
(similar to the way ours does).
As
they grow, and some species can grow to more than 10 times their birth
size, the
structures that make the sounds also grow. Generally, the "peak
frequency" of their calls lowers. That is, their voices get deeper.
There is mention that adults respond more rapidly to higher-pitched distress
calls, than to lower ones. I surmise
that after a certain point, the adult no longer recognizes or responds
to a distress call that falls outside a certain frequency window. Although
they still may make
distress calls, the adult will not respond. I also
believe that with this comes another behavior, where the young alligator
has become large enough to be recognized as a threat to the current brood,
and
may be chased off. I see many
alligators around 3 feet long by themselves at the park. I see few
between 2 and 3 feet long alone. If this interests you at all, I
urge you to locate the book, and either buy it
or borrow it. The book is
a collection of different papers by different study groups. Much of it
is quite technical, but it's still interesting.
August
25, 2002Most
important news: BABY ALLIGATORS at the park! Readers may recall that
a few weeks ago (see heading August 18 above) the park naturalists had
to relocate 28 eggs from an alligator
nest that had flooded. On Wednesday,
August 21, the eggs hatched! Actually, 19 of the 28 eggs hatched. The remaining
9 eggs turned out to have been infertile. Not bad! Not bad at all! I wish
I could have been
there, but alas, I was at work, and the eggs began hatching
around 3:00 pm. However, today (Sunday) I was able to visit the new additions
to the park. The image below (SOME HANDFUL) shows my hand
holding some
of these new alligators. The young gators were surprisingly docile, and
did not show much alarm at my approach. Of course I only handled these
animals with permission from the park naturalists.
More images of these
4-day-old babies follow.
They
are about 9 inches long (YOUNG SIZE, below). We have 3 live alligators
in the Visitor's Center that were born almost a year ago. Here are
two pictures
comparing the two. Note that the young in the VC are not fed
as often as they'd like to be, but they *do* eat all year.
SOME
HANDFUL
YOUNG SIZE
COUSIN?
BIG
DEAL, ONE YEAR
Therefore
the wild alligators may be a bit larger than this one. (see COUSIN?, and
BIG DEAL, ONE YEAR, above). Even after 4 days, the yolk sack they are born
with is still visible (see YOLK SACK, below)
Like
many other reptiles, alligators are born with a "Developmental Chamber
Escape Tool" (my term), otherwise known as an "egg tooth". This is
a temporary sharp "tooth" that is usually at the tip of the skull
(near
the nostrils), that is used to tear through the egg membrane, and sometimes
the softer shells of reptile eggs. Sometime later, this "tooth" falls off.
Here is a young alligator's face (see BABY PICTURE,
below) and a close-up
of the egg tooth (EGG TOOTH, below). The egg tooth is the white triangular
spot on the tip of the snout. The entire young alligator, as it lies quietly
in my hand (IN MY HAND, below).
YOLK
SACK
BABY PICTURE
EGG TOOTH
------IN MY HAND
Also,
David (park naturalist) attempted to give these young alligators their
first meal. Remember, there are born with a yolk sack, and this sustains
them for their first few days of life. Two of the young alligators
did take the food (large chunks of diced earthworm...LE YUM!), while most
of them ignored it; although a few did bite on the worms, chew them and
spit them out. I was able to get a few film clips of this first
successful
feeding.
Here
are three links (the pictures below are from the clips):
4-day-olds,
with a few chirps. (flv video 433kb, see BROTHERS AND SISTERS , below)
4-day-old's
first attack (real video 503kb, see AM I SUPPOSED TO EAT THIS?, below).
4-day-old's
first prey (flv video 478kb, see MMMMM...BOY!, below).
BROTHERS
AND SISTERS
AM I SUPPOSED TO EAT THIS?
MMMMM...BOY!
This
was a pretty successful hatching. Usually, the mother alligator would have
assisted with this hatching. That means that when the babies started croaking,
the mother would have gently scraped the top off
the nest and helped the
babies leave their eggs. The mother gators have been observed gently cracking
the shells in their jaws, and carrying the live babies to the water.
Even after the hatching the mother will
protect her young, for two years
or so. In spite of all this protection, one alligator in 60 (yes--ONE
IN SIXTY) will survive the first 3 years of life. This high mortality rate
is due mostly to predation by numerous
animals which view young alligators
as a food item. These can include snakes, turtles, wading birds, fish (remember
the giant alligator gar we found at the park?), raccoons, river otters
(these have been
observed at Brazos Bend State Park), and other alligators.
A particularly severe winter can also cause smaller alligators to die.
Therefore, I considered myself very lucky to be able to observe such a
group
of newborn alligators so closely.
June
30, 2002 It had been raining all weekend.
Not steadily, but enough to make things wet and the air close and sticky.
I hadn't been at the park very long, before it started raining on me. I
was near the
water station on Elm Lake Trail, and between that point and
to about 75 yards past the first pier, I saw 8 alligators lying still in
the water. For at least 15 minutes, all the alligators were unmoving, and
facing
the trail (SEE RAINY MORNING, below) . Two smaller alligators
were very close to the shore, and one of them is the rickubiscam shot for
this week. After this brief period of stillness, during which the rain
paused for a short time, the the some of the alligators began moving around.
There were two larger alligators (probably males), near in the group. Two
of the mid size alligators (about 6 feet long) started
moving first. The
alligators slightly tilted their heads as they swam, showing the their
lips above the surface, but keeping the head almost horizontal. They also
showed most of their upper back and tail as
they swam at a leisurely pace.
Eventually, all the alligators had scattered.
The
rain finally stopped, at around 10:00. I wandered the trails for
a while, which were clear of visitors.
Sometime
later, I, and a couple others, went to visit one of our new alligator nests.
Alligators build nests during this month, and two have nested within easy
sight of one of our most accessible trails, the Creekfield
Trail. The first
nest is about 10 minute's walk from the Visitor's Center, and close enough
to be seen easily from the trail, yet far enough away from the trail for
the mother to be undisturbed (and therefore not
moved to vigorously defend
her nest). Although we are far enough away from her nest, the female
is definitely keeping an eye on us. See SHE'S WATCHING ME, below.
She is actually behind the nest (from
the viewpoint of the trail). The
nest is the pile of old grass and logs in front of her. This female
has put some pretty large pieces of wood into her nest. If her nest
remains unharmed (unfortunately, there are many
raccoons in the area she
chose), she will guard her nest for the 60 days required to incubate
her eggs. This is one of the largest females-if not the largest-that
I've seen at the park. It's not possible to be 100
percent sure of an alligator's
sex unless one does a physical examination, but nest-guarding behavior
is not shown by male American Alligators.
------------
RAINY
MORNING
SHE'S
WATCHING ME
MY VISITOR
August
18, 2002Most
important news: WE GOT RAIN at the park! About 9 inches worth, and now
the park looks like it should. Unfortunately, the two alligator nests
by the Creekfield trail were threatened by the
raised water level. In fact,
one nest was totally submerged, so the eggs were relocated. The other
nest was left alone, since the top of it was still above water. The
nest looked like this before the rain (see DRY
NEST, below.) And now, it
looks like this (see WET NEST, below.)
DRY NEST
WET NEST
September
23, 2001. Have I mentioned that I think
alligators are pretty cool? Of course I have! Maybe I haven't made this
clear. Actually, I'm not doing this to make anyone believe they
are interesting. I do this
because I already think that they are.
Alligators are not typical reptiles. They are among the largest living
reptiles. They have a 4 chambered heart (other reptiles have 3 chambers),
and they protect their
young for up to two years. This time, I was fortunate
enough to encounter a litter of baby alligators (BABIES!,
below), along with their mother...or at any
rate, an adult alligator who was very protective. I'd already
heard
of her...interactions with some of the park staff. The water level was
still high at the park, so the water came up very close to the paths. When
someone approached too close to her brood, the mother
would hiss, and/or
slap the water with her tail or jaw (by slapping with her head). At this
point, the prudent person leaves the area. At Brazos Bend Park, the
alligators have the right of way at all times.
I approached to
about 15 feet, and then let the video camera do the work of zooming in
closer. The mother alligator kept a close eye on me, anyway. Here
is a video clip of the alligators and their protector
.
(flv video 747kb)
If you'd like to know more about the park follow these links:
Brazos Bend State Park The main page.
Brazos
Bend State Park Volunteer's Page The
volunteer's main page.
Go back to my main alligator page, Alligators
Go back to my home page, Welcome
to rickubis.com
Go
back to the RICKUBISCAM
page.
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back to the See
the World page.