Alligators usually follow a series of non-violent behaviors when interacting with each other. But they are animals, not machines, just like we are. People, which are supposed to be "civilized", may react savagely if provoked in the right way. The same can be said for any of our domestic animals. Occasionally, even alligators will react violently towards each other. It is foolish to provoke any wild animal, regardless of size or disposition. The animals have a right to live in their habitat, and humans can share it with them if they take the time to understand the animals.
May 13, 2012-- I
was on my bicycle on the Spillway Trail, heading towards Elm Lake. I
was about 20 yards from the West end of the Spillway Bridge when I
heard a loud splash. Since a loud splash at Brazos Bend
State park frequently means an alligator has caught something, I turned
around to look for the cause of the disturbance. I found the source of
the splash. There were two alligators, about 7 feet long, biting
onto each other. They had each grabbed the other near the
hindquarters--near the base of the tail. When an alligator expends the effort
to attempt to crush something, shake something, or twist something in
its jaws, it usually has to rest for a while afterwards. This rest
period can be from 5 minutes to a half-hour long. I saw this
behavior during the hour or so that I watched these two. I shot some
photos--but mostly video--during that time. The images below are from
the video clip (41 mb) that I shot today.
It was still mating season, so it was not unusual to see two alligators in this kind of disagreement. At first, I thought that this was an odd situation, since the alligators attack and defend with their jaws. But on further thought, it does make sense. Many alligator interactions are very subtle, and postures of dominance and submission are usually performed with a minimum of movement and speed. The submissive alligator will usually turn and swim away, and is occasionally followed by the dominant one. And...sometimes the dominant alligator will increase speed, and chase rapidly--and will sometimes clamp jaws on the retreating alligator. The "clamp" usually brief (especially if the two are similar in size). But, what would happen if the chasing alligator grabbed the retreating alligator by the base of the tail, and the retreating alligator curved itself back and bit the chasing one? It couldn't bend its body too sharply, and so would probably clamp its jaws on the other alligators' hindquarters (where it could reach). The result would probably look very much like the situation I found.
The alligator on the right seemed to have the better grip. The right alligator would occasionally try to shake the left alligator. It might have been trying to roll as well. But when the water turbulence subsided, I could see that the left alligator had clamped its jaws around the body of the right alligator. That would prevent the right alligator from slinging the left alligator around.
The alligator on the left would sometimes open its jaws and let go. But the right alligator did not respond by opening its jaws. So the left alligator tried to clamp onto the right alligator again.
It would try to get its jaws around the right alligator's body. While it tried to do this, I could see (and hear) the teeth of the left alligator scraping on the back (and osteoderms) of the right alligator. BOTH alligators would try to crush whatever part of the other alligator was between their jaws. I could tell by the heads jerked while the jaws clamped and the huge jaw muscles expanded with the effort,
When the right alligator would begin its shaking movement, I noticed that it would turn the top of its body counter-clockwise (towards the left). Of course I can't tell if this was a preferred movement, but it seems to me that the alligator could have turned either way. What's interesting about turning to the left is--in this situation--it would turn the osteoderm-covered back of the alligator (and not the softer underside) towards the teeth and jaws of the other alligator. This would would use those surfaces to the best advantage for protection.
I've a read a number of items about the cost in energy and food for growing those disks of bone (the osteoderms) on the alligator's back. For alligators to have expended those
resources for millions of years, osteoderms must be useful for something. I've read that they serve as support structures to reinforce the spine, and also as an aid in thermoregulation.
They are often referred to as "armor". References to these and other purposes of osteoderms can be found in: "Internal vascularity of the dermal plates of Stegosaurus
(Ornithischia, Thyreophora)" by James O. Farlow, Shoji Hayashi, Glenn J. Tattersall; specifically pages 8-9 (the section called "Function of alligator osteoderms"). Other studies can be found in the "references" section of that paper. It can be found online here: http://www.brocku.ca/researchers/glenn_tattersall/PDFs/farlow et al stegosaurus.pdf
In my videos here, it seems that they are acting as a sort of armor. Since the osteoderms can be used to redistribute various mechanical stresses on the skeletal structure,
perhaps they could also be a mechanism for redistribution or absorption of the compressive stress from another alligator's jaws. At least, that's how it seems to me. But, that's
just a guess on my part.
I watched these alligators for about an hour, but I had to leave to conduct a scheduled hike. By the time I was able to return to the area, I couldn't find any wounded alligators that I could be sure were one of these two. Once again, here's a link to the video clip (41 mb).
---- EXHALATION INHALATION
I have also uploaded two edited video clips to my web host. Here they are: Wounded alligator 1 Wounded Alligator 2
observed the alligator over 5 or 6 weeks, and it remained in the
same area of the lake. During most of that time, the wound was covered
by a mat of algae and various plants. When I did get a good view of the
wound, it seemed to be about the same. We didn't expect that the
alligator would die from infection. Studies have proven the antibiotic
properties of alligator blood. Basically, alligator blood is
an antibiotic all by itself--having demonstrated an ability to
kill many kinds of fungus, bacteria, and virus pathogens. Ongoing
studies continue to see if this antibiotic property can be used to
During the weeks I watched the alligator, many people (park visitors, and I) wondered what we were actually seeing inside the wound. What was that "membrane"? I wrote to a few people who would know about this, and got a reply from Dr.Leon Claessens. I was also able to look at his article, "A Cineradiographic Study of Lung Ventilation in Alligator mississippiensis", (Claessens LPAM. 2009. A cineradiographic study of lung ventilation in Alligator mississippiensis. J. Exp. Zool. 311A:563–585.). The article is very detailed, and quite technical. However, Dr. Claessens' explanation helped clarify it for me. This is what I understand was going on, and the pictures will help me explain.-
-Alligators have thin bones called "gastralia" within their abdominal muscles. (figure 2). These act with the muscles to allow the abdomen to be expanded and compressed with extra force. Other structures that assist in respiration are muscles (diaphragmaticus) that attach to the liver. These pull the liver back, which expands the lung cavity. The spine can flex up and down to a certain extent; and this also helps expand the lung cavity. During inhalation, all of these work together (Figure 4) to increase the volume of the lung cavity. The lungs and heart are also enclosed in a large "sack". In normal conditions, when this volume in increased, air rushes into the lungs to fill the void. But this alligator had that huge breach which prevented that expansion from pulling air into the lungs.
FIGURE 1 FIGURE 2 FIGURE 3 FIGURE 4
In normal conditions, when this volume in increased, air rushes into the lungs to fill the void. (figure 5) But this alligator had that huge breach which prevented that expansion from pulling air into the lungs (figure 6). So, instead of that nice expansion filling the lungs, the liver is pulled back, and then the collapsed lung and other organs are pulled back. (figure 7) But, this is just the physical movement of soft materials. Then, when things relax, and the lung cavity contracts--that same mass of soft materials is just squeezed forward again. Since that connective sack holds everything together, the soft materials "fill it back up" and it is pressed against the inside of the hole. (figure 1) One lung was probably collecting some air, but there was no chance the the alligator was getting its full amount of air. I've simplified this quite a bit. Alligator respiration is a complex process using integration of many structures and processes.
The alligator was finally reported dead on 6/11/2011. When I went to the park the next day, I couldn't find the carcass. It appears that something (probably an alligator) had dragged it off. For further information, you can see Dr. Claessens' work here: Claessens Laboratory. Also...a big thank you to Dr. Claessans for taking the time to answer my email, and for his generosity.
FIGURE 5 FIGURE 6 FIGURE 7
This is nearly the final act of a drama that seems to have started
A six-foot long alligator was seen in the jaws of a much larger alligator Wednesday. Rich witnessed the dead alligator being carried from 40-Acre Lake to Pilant Slough by passing under the Observation Tower bridge sometime Wednesday afternoon. This same alligator stayed near the Observation Tower in Pilant Slough for the rest of the week. During this time it continued chewing on the deceased alligator. If I understand correctly, David feels that the large alligator abandoned the carcass a day or so before Sunday. After being abandoned by the large alligator, the carcass was claimed by another alligator, estimated at about 10-feet long. It then stationed itself in the same area occupied by the previous larger alligator. The second alligator is the alligator pictured here.
I was lucky enough to briefly see some of this Sunday afternoon 4/24/2005. (I saw it very briefly Thursday morning, but couldn't stay to watch, then.) As more visitors passed by the observation tower Sunday afternoon, they got to see the occasional carcass-thrashing as the alligator tried to fragment the remains. The image above (CHOMP) is a picture taken during one of the chewing intervals. The caption refers to the fact that, well, the alligator is eating seconds, and they are obviously "sloppy" (see TASTES LIKE CHICKEN, and CLOSER, below).
TASTES LIKE CHICKEN CLOSER VIEW READY TO WHIP
WISH I HAD A KNIFE! PREY WHIPPING VIDEO(543kb)
the day, a pattern became obvious as the alligator would lie
for a long time (15-30 minutes) and then thrash (or whip) the carcass
just a few moments; and then rest for another long interval. The
image above (READY TO WHIP) shows the alligator preparing to whip the
by lifting its head, front part, and the carcass off the ground. You
see that the head is still attached to the carcass is and hanging below
the live alligator's jaw. The next image (WISH I HAD A KNIFE,
shows the end of the whip arc as the alligator has swung its head from
our left to our right. These are 2nd and 3rd in a series of 5 images I
shot in a burst. I discuss more of the mechanics of the prey-thrashing
on one of my other pages, here.
I've also got a short
taken before the other pictures, of this prey-whipping motion.
see the image of a single frame from the clip above (PREY WHIPPING
I had a lot of fun talking to the visitors about alligators in general for a few hours that Sunday. While there were about 20-30 people near the Observation Tower, I was looking through my camera when I heard a number of voices raised in suprise. When I turned towards the voices, I saw that an alligator (about 8 feet long) was crossing from 40-Acre Lake to Pilant Slough by walking over the trail--maybe about 12 feet in front of the water station. It was taking advantage
of a large gap among the visitors. After I shouted to "give it space", and "just let it pass", everyone moved back a bit, and the alligator made its slow way across the trail and down into the Slough. The crowd was entranced by the event, which took a few minutes.
It was EXCELLENT! Unfortunately, I had the camera turned towards the other side of the Slough, with a tele-adapter on it, so I couldn't get a shot of this alligator calmly walking past (through) the large group of people. I confess that I was concentrating on the crossing alligator and making sure everyone was a safe distance from it through most of this incident,
so I didn't really think much about looking away long enough to readjust anything, anyway. It was also a good opportunity for more interpretive material on alligators and of course I used it. Sharon was also nearby during this as well, and I
believe she also got to see the whole thing.
Why, or how the smaller alligator came to be deceased is unknown to me at this time. Many of us suspect that this was the outcome of a territorial conflict, but no one saw the kill. Alligators become mature at about 6 feet long (6 years of age). The dead alligator is estimated to be about 6 feet long. Alligators are territorial. The larger alligators will have the largest, "best" territories, and there are potentially alligators of all sizes and ages withing a single territory. On any year, in a healthy population of alligators, it stands to reason that there could be at least one newly-mature alligator in any one territory. This alligator will seek to mate, and claim an area. It will announce these intentions by bellowing, headslapping, and so on. Unfortunately for the new adult, these signals may not only attract a potential mate--they can also attract at larger alligator that has already claimed the vicinity. I've seen this type of situation myself.
One one of these occasions, I watched as two smaller males (about 7 feet long) bellowed about 20 feet apart. I thought that they might challenge each other. But, before this could happen, a much larger male (at least 10 feet long) came cruising from around one of the islands and went straight towards the two smaller males. They both turned and swam away from the approaching large male.
If either one of the smaller males decided to challenge, it could have been interesting, but it could have resulted with the smaller one's death. It can be seen by these behaviors that an alligator population can control itself. Hunting or culling by outside influnce is unnecessary--providing that the large alligators are left alone. Killing the largest alligators (As some people want to do for "trophies"--what a ludicrous concept. Why not shoot a log and hang that on a wall? No challenge or sport in killing an alligator.) only leaves large territories open for smaller alligators to split, and allows more smaller alligators to inhabit an area.
This has been one of my better days, that's for sure.
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.
Here are a few links to more information on alligators. There's a LOT of it out there.
Adam Britton's Pages 1
Adam Britton's Pages 2
Fish and Wildlife Page (Text)
Fish and Wildlife Endangered Species
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.