Most people have seen programs on television showing crocodiles attacking large animals like deer and cattle. While this is amazing, and sometimes horrifying, those creatures are not alligators. The function of a crocodile's dentition is somewhat different than an alligator's. Alligators favor prey items that will fit inside their head. That is, if they can swallow it whole, then they will normally attack it. While I've heard witnesses tell of alligators taking deer in the park, the prey was very small fawns. Alligators have also been seen with large nutria. But, most of the time, they will eat things like small fish, frogs, and crayfish. Snakes and turtles are also pursued, with alligators seeming to be especially well-adapted for eating turtles. A recent study done in Texas examined the stomach contents of about 50 alligators (which were unharmed). Research showed that only one of these alligators had eaten a bird (which couldn't be identified, it might have already been carrion when taken), and the rest had stomach full of small fish and shellfish. I've seen 11-foot alligators going after prey that was no larger than their largest teeth (very small frogs and fish).
April 19, 2015--
After the heavy rains that came last Friday and Saturday, I was looking
forward to seeing what BBSP looked like. I wasn't disappointed. Water
levels in the lakes high, and water moved slowly under the Spillway
Bridge, since Pilant Lake was almost the same level as Pilant Slough.
All the rain probably lowered the general water temperature; and it
also covered much of the lower banks of the islands and around the
lakes. And the Sun was bright. So....this meant that many alligators
were out of the water, and near the trails. There were many sightings
of alligators crossing trails.
During conditions like these, it is especially important for visitors to be aware of "alligator etiquette", and there are many opportunities for "teachable moments"; especially for those of us doing Trail Interpretation. After all, we are right there with the alligators and the visitors at the same time.
The two photographers were actually concentrating on a large alligator on the bank of Elm Lake when this one began crossing the trail behind them. I called out an alert, and they turned around to
watch (and film) the crossing. Meanwhile, the gator crossed until it got close to the other, larger one. *I* expected some kind of interaction, but nothing immediately happened. But,then, without any signal I could see (otherwise I'd have filmed it), the large one rushed the smaller one (still about 7' long), causing it to submerge and swim off. This sudden burst of motion is hard to catch (because there isn't much warning), but is a definite demonstration of how quickly an annoyed gator can move. The larger gator returned to the bank, but not before lying in the water and swishing end off its tail back-and-forth (much like an annoyed cat does), before it slid back up on the bank. It appeared that it just wanted the nice basking spot for itself--no sharing. I've
edited photos and video into short clips: Click the links to see it--Gator Walking 04192015.wmv
MORNING WALK ON THE TRAIL WATCHING THE ONE ALREADY THERE ANNOYED AND THRASHING TAIL
Then there was the group of gators in front of the composting restrooms. The new front deck made a handy path around the gators. There, also, was a nice shallow bank for the gators to bask on. I saw another minor disagreement between 2 gators there, also.
When one of the John Deere vehicles drove by, 2 of the alligators slid into the water. But , after just a few minutes, one of the gators slid back up on the grass. However, this was in the spot where the larger gator had been basking. The larger alligator came back to the bank, and looked at the gator on the grass for a few minutes. When the staring didn't work, it moved into "head oblique/tail arched" posture...and then did a loud headslap. This did not impress the other alligator, which gave a low growl. The larger gator then settled for moving up onto the grass right next to the "good spot:" I've edited photos and video into short clips: Click the links to see it--Gators Basking argue 04192015.wmv
GATORS BY THE BATHROOMS LOOKING DOWN FROM THE DECK HEY! YOU TOOK MY SPOT! THE HEADSLAP
Then at about 12 pm, I was on walking towards New Horseshoe Lake when I noticed a group of about 10 people looking down into the lake. When I got there, I saw that a large alligator had a deer carcass in its jaws. I was happy to see that most of the park visitors were giving the alligator a lot of room. I watched and was able to talk about how the alligator would probably deal with the carcass (it was NOT a small fawn). I didn't see many other alligators around, but there was another large on on the bank nearby. I suggested that the gator with the carcass was probably trying to leave the New Horseshoe to get into Elm...mostly to keep the carcass for itself. I also told those visitors who remained nearby that the we should stay out of the direct path of the alligator, and give it lots of space. If we did those things, we'd probably see the alligator cross with the carcass. And...the alligator *did* start across....a couple times. But each time it lifted its head (with dangling carcass) and began to walk, it would step on the carcass....and of course didn't get far. Then it would stop and rest a few minutes more. Finally, the alligator did an odd sort of "plowing" movement and pushed the carcass and slid it forward.
NEARER THE WATER IN NEW HORSESHOE LAKE MOVING UP ONTO THE LEVEL GRASS STARTING TO SLIDE ACROSS THE TRAIL
The attached pictures show some of this...and I attached the animated gifs to show the movement. During all of this, I was able to share my theme of how alligators don't have it easy--even as "apex predators". I pointed out the effort the alligator was expending just to keep its meal--and also that it could take days for the gator to even be able to get it into pieces small enough to eat.
The alligator finally got into Elm Lake, and swam off with the carcass. One thing I forgot to do was take an immediate length estimate by using my walking stick. But, compare the length of the alligator with the width of the trail. I thought the deer was surprisingly large, and could only guess at how the alligator had gotten it. The carcass didn't stink, and there were no flies on it--so it wasn't too old. Maybe the high water trapped the deer?
I've edited photos and video into a short clip: Click the link to see it--Gator with Deer 04192015.wmv
CATCHING WITH THE LOWER JAW STANDING UP TO PUSH FIRST PART OF THE SLIDE SECOND PART OF THE SLIDE
All of this happened in just ONE day! It was great!
It was cold and raining, and generally uncomfortable outside. The
near-80's weather that we'd had a week or so before had gone away. As I
stepped on to the Spillway Bridge, I found this alligator with a small
nutria in its mouth. After one shift in position the alligator didn't
move again. When I left it, I walked to Elm Lake; and around Elm Lake.
When I retured along the bridge, hours later, the alligator was in the
same postion as when I had left it. I suspect that the lower
temperatures slowed the alligator's movements. I've seen an alligator
work on a nutria for hours!
While I was at Elm Lake, I stopped at the Observation Platform,
where I saw a bright red Vermilion Flycatcher that seemed to glow in the
overcast grey air.
NUTRIA AT THE BRIDGE NUTRIA FROM ONE SIDE FROM THE OTHER SIDE Vermilion Flycatcher
April 21, 2013 (update added 1/10/17) An
alligator had claimed the corner of Pilant Lake where the East end of
the Spillway Trail meets Elm Lake. When that happens, the dominant
alligator chases other alligators--and other animals that are fishing--away from that area. A week or so before, a park visitor had his backback stolen when
he'd left it on the bank while he was fishing. The alligator followed the fish the visitor had dragged out of the water, saw the backpack, and grabbed that
instead. It eventually left the backback out in the weeds.
So today, when I saw the alligator chewing on something dark, I thought it had the backback again. That is, until the alligator shook the bundle and a huge wing
extended. The alligator had a Great Blue Heron! I've seen alligators chase wading birds out of their "fishing holes". I watched one alligator follow a Great Blue
Heron-that had taken a fish out of the gator's puddle-into the woods as the heron tried to eat the fish. So, I believe that this Great Blue Heron annoyed the alligator
enough for the alligator to attack it. The images below are photos and frame grabs from the video I filmed. The video is through this link.
August 28, 2011 As
the water evaporated out of Pilant Lake (and the other lakes, too) at
Brazos Bend State Park through our dry summer, the deeper spots
became collection areas for all kinds of aquatic life. Or, as it might sometimes be known...alligator food. The southeast corner of Pilant Lake (right near the
intersection of the Spillway Trail and the Elm Lake Trail) remained wet through the entire summer. As the water evaporated, fish and other life collected
at that Southeast corner. Through the summer, that corner became a desired feeding ground for the alligators. Early in the summer, the corner was claimed
by an 8-foot long alligator that had a big scar that ran along the left side of its head, through the eye and into the ear flap. The pictures below show this
alligator near that corner of Pilant Lake on February 20, 2001--that is, earlier this year.
THE SCARRED ALLIGATOR LEFT SIDE BLINDED EYE, DAMAGED EAR
However, sometime later, "Scar" was chased off by a somewhat larger alligator--one about 9 feet long. From sometime in June, this larger alligator
maintained control of the corner puddle as it dwindled in size. There were a lot of opportunities to watch alligator social interaction.
As the water became shallow throughout the park the alligators took advantage of the prey caught in the dwindling pools. There were many opportunities to
watch alligators trapping food with a technique that I call "seining". This page of mine shows the first time I noticed this behavior, back in 2002 (with some
movie clips). Basically, the alligator uses its body as a barrier to trap prey, usually against the bank of a pond; but sometimes the alligator will "dam" a
section of water. While using its body as a barrier, the alligator may also move one of its forelegs (usually the one closest to the bank) in the water and/or
move its tail. Both of these motions can herd prey towards the alligator's head. Sometimes the alligator will move its tail from side-to-side in the swimming
motion that normally moves the alligator through the water. But, the alligator remains standing, so this movement thrusts the water away from the alligator--
which generates a current. The alligator sometimes turns the end of its tail so that the current moves towards the alligator's head from the rear; sometimes
it pushes water away to the rear--but in a small pool, this causes the current to move in a circle and towards the front of the alligator's head. Most of the
time this is an effective technique, since most creatures seem to move where the alligator wants them to (which is eventually towards its head and jaws).
This leads to my story here. Trapped in the Southeast Corner of Pilant Lake were, among other things, a bunch of gar. These appeared to be longnosed gar
...but there may have been some spotted gar as well. Gar, seem to be a bit more crafty than most other fish, as shown here. Although the gar *were* being
herded to some extent; beyond a certain point they figured out that they could get past the alligator. They would do this either by swimming *up onto the
mud*, and then past the alligator; or...by simply jumping over the alligator! I caught some of this activity in video with the high-speed camera. Although
the alligator was successful sometimes--sometimes it was not. At least, while there was still enough water for the gar to swim in. The images here are frame
captures from some of the video. And, here is the video clip (wmv 30mb). I enjoyed watching the daredevil gar.
ESCAPE OVER THE TAIL
Here, the alligator was blocking off a narrower section of the pool. It moved its tail, and occasionally the right foreleg to flush the fish and panic them
enought to try to swim past the alligator's head. This gar jumped over the safe end.
JUMPING GROUP OF GAR 1 JUMPING GROUP OF GAR 2 JUMPING GROUP OF GAR 3 JUMPING GROUP OF GAR 4
The alligator would sometimes go into the deeper spots to flush fish towards the shallower edges. Then it would move towards the edges.
The gar had other ideas here. Instead of swimming away in panic, a group of them jumped over the alligator's back. This group of 7 images
shows the jump.
JUMPING GROUP OF GAR 5 JUMPING GROUP OF GAR 6 JUMPING GROUP OF GAR 7
FLUSHED FROM BEHIND 1 FLUSHED FROM BEHIND 2 FLUSHED FROM BEHIND 3
FLUSHED FROM BEHIND 4 FLUSHED FROM BEHIND 5
stirring things up in the deeper water, the alligator moved
towards the edge to see what moved there. It was on the tail of a gar,
but not for long. It might possibly have caught the gar...if the gar hadn't left the water! This group of 9 images shows the jump.
FLUSHED FROM BEHIND 6 FLUSHED FROM BEHIND 7 FLUSHED FROM BEHIND 8 FLUSHED FROM BEHIND 9
These last 3 images show the alligator encircling an area with its body, tail, and head! In the video, trapped critters
can be seen moving around in the trap. As the alligator turns its head, ready to close the trap, this gar leapt over
the "seine" to safety. One can see in these images (and in the clip) that this alligator has a good left eye. (unlike the
scarred one, above). Once again, here's the link to the video clip (wmv 30mb).
February 6, 2011:
is probably aware of the recent bout of cold weather we've had.
Starting sometime Thursday, the temperature dropped from around 69
degrees F to somewhere in the 20's--and stayed there through Saturday,
night. Sunday morning still had temperatures in the 40's, although by
afternoon it got up to 70 degrees.
Sunday morning, Feb.6, 2011, while it was still cold, I saw an alligator at the Spillway. The alligator had a nutria in its mouth. Since water was flowing over the Spillway, and with the alligator there; I closed the gates at both ends of the bridge.
I've read that alligators can't digest if their core temperature falls below 70 deg. F. As I mentioned above, air temperature was well below that for about 3 full days and nights. It's hard for me to believe that the water temperature anywhere was much higher than that, even in the deepest spots. So, the alligator must have been cold. This is also the extremely thin alligator that's been in that area for some months. And, the alligator is *blind* in both eyes! How did it catch the nutria in the first place? Today's RICKUBISCAM shows that alligator, illustrating the prominent backbone. The stick on its head is most likely there by accident. I've often seen alligators with such "headgear". This can happen if they surface under a random piece of floating debris. The images below show the alligator face in closer, and a close up of the face to show that the eyes are gone.
I thought this was an
interesting mystery. So, I looked again at information on how
alligators control their temperature. I
found these two studies about alligator thermoregulation. There are a
lot of factors that influence the internal temperature of an alligator.
Besides the general weather factors (sunlight, temperature) there is
the alligator's external behavior (moving in and out of the water,
turning towards the sun, gaping) and internal behavior (circulation,
respiration, and metabolic movement) and various other factors.
Temperature exchange happens faster in water (since it conducts heat
better than air), but it is a more stable thermal environment than air;
and is slower to change condition. So, alligators use water as a
An alligator heats up faster than it cools off (at least larger ones do--small ones heat and cool at the same rate). Alligators are efficient heat pumps.
Brazos Bend State Park The main page.
Brazos Bend State Park Volunteer's Page The volunteer's main page.
Here are a few links to more information on alligators. There's a LOT of it out there.
Here are my "alligator behavior" pages:
|SOCIAL INTERACTION||CONFLICT AND CANNIBALISM||FEEDING||BABY ALLIGATORS||ALLIGATOR DENS||ALLIGATORS ON LAND||FOSSIL CROCS|
|SIGNALS 1||CONFLICT 1||FEEDING 1||BABIES 1||DENS 1||ON LAND 1||FOSSILS 1|
|SIGNALS 2||CONFLICT 2||FEEDING 2||BABIES 2||ON LAND 2|
|SIGNALS 3||CONFLICT 3||FEEDING 3||BABIES 3||ON LAND 3|
|SIGNALS 4||FEEDING 4||BABIES 4||ON LAND 4|
|SIGNALS 5||FEEDING 5||BABIES 5||ON LAND 5|
|SIGNALS 6||FEEDING 6||BABIES 6||ON LAND 6|
|SIGNALS 7||ON LAND 7|
And, this page shows alligators at the park, on land, near various landmarks at the park.
Go back to my main alligator page, Alligators
Go back to my home page, Welcome
Go back to the See the World page.