2010 RUNNING & TRAVEL ADVENTURES

 

   
 
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BRAZOS BEND STATE PARK, PART 6: 
IT'S TOUGH TO BE A BABY ALLIGATOR

FRIDAY, MARCH 26

 

"Survival rate of hatchlings is very low. Only about three or four hatchlings out of a hundred
are thought to make it to adulthood. They are preyed upon by fish, wading birds,
hawks and owls, river otters, raccoons, turtles, and other alligators."

~ from a Brazos Bend information sheet about American alligators

 
 

There's that food chain thing again.

Baby alligators are only about six to eight inches long when they hatch in August or September. Although the pod of 30-60 hatchlings stays close to mama for six months or more, mother alligators cannot protect each little 'gator from all the predators out there.

Three to four percent is a really low survival rate!

Above and below:  seven-month old baby 'gators hide near their mama (3ed picture)
in the grass along the shore at 40-Acre Lake; I counted at least twenty babies.

 


Mama to the babies above

These little guys are already predators, however.

The pink yolk sack that protrudes from their stomachs when they hatch provides food for about a week. The mother doesn't provide them with any food. If they're lucky, they might find some food scraps she left behind. Mostly they're on their own. They eat whatever they can fit into their tiny mouths: insects, worms, crustaceans, minnows, tadpoles, and frogs are usually on the menu.

Fortunately, alligators require very little food from October to March. That helps prevent mom from eating her young! (See section farther below about the diet of adult alligators.)


Best 'gator picture ever! Photo taken at Brazos Bens SP in 2004 by Trey Neal.

The baby 'gators that do survive in the wild grow about one foot a year up to six years of age, when they are considered adults and their growth rate slows down. As they get bigger and smarter the odds of survival increase in their favor . . . and their menu choices broaden to larger and larger prey such as fish, snakes, wading birds, hawks and owls, river otters, raccoons, turtles, deer, and other alligators.

If you remember from the opening quote, most of those are the same critters that like to eat tender baby alligators!

That's some cosmic justice, eh? What goes around, comes around.

LET'S GO SEE SOME ALLIGATORS!

We aren't the only visitors drawn to Brazos Bend SP because of the alligators. They are one of the main reasons the park is near the top of the popularity charts in this whole country, not just in Texas. This is quite possibly the best place to see a healthy, un-hunted inland alligator population.


A ten-foot alligator makes himself right at home next to the Spillway Trail.

Brazos Bend is home to about three hundred adult American alligators that are six feet long and over. There are many others that are younger and shorter.

Above and below: we often saw these two buddies below the Spillway bridge; they are 7-8 feet long.

This population has held steady since the park opened in 1984, which says something about the balance of the park's food chain; hunting or relocation to lower the number of 'gators hasn't been required so far.


Another big boy farther along the Spillway Trail;  Pilant Lake is to the right.

Brazos Bend wasn't on our travel radar until near the end of February when we attended a naturalist's talk about alligators at Huntsville State Park. We've never seen any alligators in the wild at HSP in several extended winter visits there, although signs warning about their presence are prominently displayed around the park. We joke to each other about the "phantom" alligators, although we usually don't let Cody get in the lake, creeks, or swamps there -- just in case.

The only alligators we've ever seen at Huntsville State Park are the two cute little five- or six-month old babies that were hatched at Brazos Bend State Park last August or September.


One of the baby 'gators in the Huntsville SP aquarium;  cute, eh?

The babies Huntsville displays and uses for educational purposes are usually ones that are orphaned by their mothers and rescued by park rangers before they hatch. They live in an aquarium in the nature center. They get to come out to be petted by visitors when rangers or volunteers are manning the center and conducting weekend nature talks.

When they are about a year old, a foot long, and starting to bite, they are released into the wild -- sounds like a good plan! That's also about the time Huntsville  receives more newborns from Brazos Bend.


Seven-month old alligators swimming in a tank at the BBSP Nature Center

After that interesting and informative lecture, we just had to check out Alligator Central at Brazos Bend!

EL LAGARTO

The word "alligator" is a derivation of "el lagarto," Spanish for "lizard." These are some big lizards, but nowhere near as big as their prehistoric ancestors.

The alligators that are native to the Southeastern part of the United States are called American alligators. They are one of about twenty-two species in the crocodile family and are uniquely American. They live in freshwater or brackish swamps, marshes, wetlands, lakes, and rivers in Virginia, North and South Carolina, Georgia, Florida, Alabama, Mississippi, Louisiana, Texas, Arkansas, and Oklahoma. The largest alligator populations are in Florida and Louisiana.


American alligator skeleton in the BBSP Nature Center

American alligators were prolific in the region before humans nearly decimated their numbers through hunting and encroaching on their habitat. For a while they were on the endangered species list. Their numbers increased enough that there is now an alligator hunting season, like deer and wild pig hunting seasons, in some areas of the country. These hunts are strictly regulated.

As mentioned, there has never been a need for alligator hunting at Brazos Bend State Park because the population has remained steady since the park opened in 1984.


Alligator skull (L) and crocodile skull (R); the display at BBSP explains the differences.

Alligators that live in the wild are still a "protected" species, with rules and regulations that ensure they don't face extinction again. At Huntsville and Brazos Bend State Parks it is illegal to feed, harass, or harm the alligators and visitors are warned to stay at least thirty feet away from them.

Many of us get much closer than that on the trails around 40-Acre, Elm, and Creekfield lakes and on the Spillway Trail, a levee that bisects Pilant Slough.


A large 'gator swims silently in Pilant Slough near the trail.

Alligator farms are a growing industry to supply more readily available meat and hides to folks who like products made from those parts -- and to protect their wild cousins. Think 'gator-trimmed purses, boots, and wallets . . .

SURVIVAL OF THE SMARTEST

Alligators are in their element in the water of the swamps and lakes in their natural territory. They maneuver much faster in the water than on land. However, they can't breathe under water. They require oxygen and have to surface periodically to get it.

At Huntsville SP the alligators live in swampy areas or in dens under banks along the far edge of Lake Raven, usually not near trails.

At Brazos Bend, they live pretty much anywhere they want to because there is so much more water in that park!


These three alligators are dozing in the sun right along the trail at Elm Lake.

Visitors can see several dozen juvenile and adult alligators quite easily from the trails at Brazos Bend on warm, sunny days around 40-Acre, Elm, and Creekfield Lakes and along the Spillway Trail.

In fact, you have to be careful not to step on some of them! Visitors are often fearful of walking within a few feet of large alligators but it's safe -- as long as they don't do something stupid to frighten the 'gator! A few other people are so bold they'll get within a couple feet of an alligator to have their photo taken. That's not very intelligent, either.

The alligators are all there on cooler, cloudier days, too, just harder to spot because they spend more time under water to keep warm:


On our first day in the park Jim took this picture of a 'gator that is mostly under water.

The ones you can see are the hardiest survivors. The perils of alligator propagation are very interesting. Not only are newly-hatched and young alligators extremely vulnerable to predators, as described at the beginning of this entry, the eggs are also considered very tasty by many of the same predators.

Mama alligators do their best to outwit these predators by building a virtual fortress to protect their eggs. The large nests are so impenetrable that the hatchlings can't get out until their mother hears their high-pitched chirps and digs them out.

Alligators breed in April and May. When attracting a female, males produce a loud rumbling noise that can be heard over a mile away. We could already hear the beginning of the bellowing at Brazos Bend the last week of March. Very cool.


This cute little guy is 17-18" long, indicating he was born about 1 years ago.

A mother alligator spends a lot of time building her nest in June, usually within about thirty feet of the water so she can keep an eye on her babies.

When she finds what she considers to be an appropriate location for her nest, she clears a large area of ground. Then she gathers as much vegetative material as possible on land and in the nearby water to build a large mound that is typically two to three feet high and up to eight feet in diameter. Mud helps hold the reeds, grasses, leaves, twigs, and other vegetation together.

The mother digs a hole in the center, lays from thirty to sixty eggs inside, then packs the materials down around her eggs until the mound is solid and tight.

The nest is similar to a compost pile in that it warms up as the vegetative material composes. During the two months that it takes for the eggs to incubate the mother regulates the temperature by digging into the mound to release heat or by adding more mulch to make it warmer.

Very ingenious.


A young alligator suns him(her?)self on a fallen tree at the edge of Creekfield Lake.
Note all the green aquatic plants AKA "pond scum" sticking to the 'gator.

Even more amazing is that the temperature of the nest also determines the sex of the babies! The cooler temperatures at the bottom of the next produce females; the warmer temperatures at the top produce males. This process leads to almost even populations of males and females.

Wonder how many millennia it took for alligators to evolve like this in order to survive?


This larger 'gator is resting on a log but appears to be
floating on top of the reddish plants in the swamp water.

When the babies begin to hatch in August and September the mother literally digs them out of the mound. She picks up each egg in her mouth, carries it to the water's edge, carefully cracks it open in her mouth, and releases it.

Here's an amazing photo from a slide show at the park that shows the mother releasing one of her babies into the water:

She repeats this over and over until all the hatchlings are freed from the nest.

MINIMAL HUMAN INTERFERENCE

Unfortunately, sometimes the nests are too close to water and vulnerable to flooding -- or more often, too close to trails and vulnerable to human interference. Situations like that create unique challenges for rangers, who try to protect both the eggs and too-curious visitors without interfering too much with either the alligators or humans.

The most dangerous alligators in the parks are mothers who are protecting their eggs or hatchlings. You don't want to try to pick up a baby whose mama is nearby! That pretty much applies to any wild species of animal.


Fake alligator? This log sure looks like one from a distance!

Some of the rangers' solutions to awkwardly-placed nests are ingenious. One of them told us about a clever idea he had several years ago that redirected visitors to a fake nest he built in order to protect the real nest nearby. Mama had built her nest right on the levee trail next to one of the popular lakes. A large sign and fencing around the fake nest drew visitors' attention and they didn't even notice the real nest! Mama was happy, the nest was safe, and the babies hatched normally two months later.

Crisis averted.


Rangers sometimes have to harvest orphaned alligator eggs at Brazos Bend.
These two photos are from a video we watched at the Nature Center.


A helping hand is required if Mama's not there to crack the egg open.

Relocating a nest is a good way to kill or orphan the babies but sometimes it's the only solution. That is one way the rangers at Brazos Bend obtain alligator eggs. Another is when something happens to the mother and she doesn't retrieve her babies as they begin to hatch.

When the rangers harvest orphaned eggs they incubate them until they hatch, then release them into the wild or use them for educational purposes in the nature centers at various parks until the next summer. Brazos Bend has about six baby 'gators in its own aquarium this spring. They get lots of attention:


Trained volunteers at the Nature Center let visitors pet
the baby alligators that are kept in the aquarium.

All the other alligators do just fine with no or minimal human contact at Brazos Bend and Huntsville. The rangers vigorously enforce park rules about bothering alligators and they try to estimate how many of the critters live in the parks, but they don't feed them or do anything that would interfere with their natural existence there.

THAT'S A LOT OF ALLIGATOR!

Before American alligators were hunted to near-extinction and their natural territories were larger, they used to live longer and grow bigger. The largest alligator on record, estimated at 100 years old, was 19 feet 2 inches long! That was back in 1890 and has not been verified to everyone's satisfaction.

Since it's hard to determine the exact age of an alligator in the wild, scientists can only say with any certainty the size and age of alligators that are held in captivity. They range from 6-8 inches when they hatch. They grow about a foot each year for the first five or six years, then the rate of growth slows down as they mature.


Three large 'gators hang out on a little "island" in the slough along the Spillway Trail

The average size of a mature female American alligator is 8-10 feet; males typically grow 11-15 feet long. Max size is about 16 feet.

The naturalist at Huntsville said the alligators that live there tend to range from 6 to 9 feet long. They often get 10-12 feet at Brazos Bend, where it's warmer and there are more food sources. Jim and I have seen lots of those larger alligators here at Brazos Bend.

The average life span of a female American alligator in captivity is 35 years for a female and 53 years for a male, less in the wild.

SUPER*CROC: SIZE DID MATTER BACK THEN

Size-wise, modern alligators and crocodiles pale in comparison to SuperCroc.

One day we borrowed the National Geographic DVD titled "SuperCroc" from the park nature center. This is a very interesting video about the giant prehistoric crocodiles that roamed around northern Africa about 110 million years ago, give or take a few years.

How big? When scientists put together all the bones they excavated at one site in the Sahara Desert in the early 2000s, they were able to build a 40-foot, ten-ton crocodile that was large enough to eat some of the dinosaurs it shared turf with.

That's a lot of croc!

 
Depiction of SuperCroc by Raul Martin

This fascinating film followed paleontologist Paul Sereno and reptile expert Brady Barr to Florida, Africa, South America, India, and Australia to study and measure the largest species of modern crocodiles. A year after the fossils of "SuperCroc" were excavated, scientists had enough information and bones for a model expert to build the giant Sarcosuchus imperator.

Since then, the model has been on tour. This website gives more information about where you can see it and the science behind SuperCroc.

DON'T MESS WITH TEXAS *OR* ITS ALLIGATORS

There are signs all over this state's highways that warn, "Don't Mess with Texas!" The slogan became popular as a way to reduce litter, but it also exemplifies the feisty nature of the people in this state.

You really don't want to mess with any of Texas' alligators, either. Although the 'gators at Brazos Bend seem to ignore visitors who walk near them on the trails, they can move much faster than you'd think and they have the strongest known bite of any animal.


This large 'gator right next to the Spillway Trail has a typical "smile" on his face.
His eyes are open but many 'gators keep their eyes closed when people walk or ride by.

The basic instinct of an alligator to bite down on its prey and not let go is graphically illustrated in a story the naturalist at Huntsville SP told us. One scientist who studied alligators many decades ago conducted an experiment in which he placed a steel plate in one mature animal's mouth. The 'gator reportedly latched on to the plate, bit down, and didn't let go until its teeth had been pushed into the roof of its mouth!

I wouldn't want to think what it would do to my arm or leg.


On a warm day it's common to see 'gators with their mouths open. It's a little
disconcerting to walk by them until you know it's just a way for them to cool off.

The naturalist showed us the skull of a young alligator about four years old. It was already quite capable of tearing off the limb of many of the animals it preys on. Alligators have 80 conical teeth that are used to grasp food, not chew it. They bite off what they can swallow, then go back for another piece.

APEX PREDATORS IN THE FOOD CHAIN

What do alligators eat?

Just about anything they want to!!

I talked above about the diet of baby alligators. As they grow they hunt for larger fish, frogs, mollusks, and small mammals like mice.

Adult alligators really will eat about anything that moves. They prefer fish, turtles, birds, snakes, small mammals like raccoons and possums, and smaller alligators but they have also been known to eat deer, sheep, cattle, pigs, panthers, bobcats, bears -- and domestic pets like dogs. It is thought that a large portion of an alligator's diet is smaller alligators.

Wow. It's really an alligator-eat-alligator world, not a dog-eat-dog world!


Graphic slide from an alligator presentation we attended;
the 'gator victim is so large that I'm guessing it was lame, ill, or very old.

Alligators are opportunistic feeders, usually waiting patiently for a meal to come to them. If need be, they can move very quickly for short distances on land and farther distances in water.

Like other cold-blooded reptiles, they don't need to eat every day and they really don't need to eat all that much. A full-grown alligator can survive on something the size of a raccoon for a week. They eat very little from October to March, especially the ones that live farther north and almost go into hibernation.


Next meal?? Smaller 'gators like the 3-foot one on the left often don't live to adulthood.

It is very rare for an American alligator to maim or kill a human. They aren't naturally aggressive. You really have to provoke an alligator to get it that riled up. Ranger Dave says he's the only person to ever get bitten by a 'gator at Brazos Bend (long but interesting story). It is more likely for a crocodile to bite or kill a human than for an alligator to do so.

Unfortunately, I can't say the same for the humans who hunted alligators to near extinction and continue to crave alligator meat and consumer items made from their skins. I guess that makes us the ultimate predator.

Next entry:  Marsh Madness -- lots of things to do and see at Brazos Bend State Park

Happy trails,

Sue
"Runtrails & Company" - Sue Norwood, Jim O'Neil, and Cody the Ultra Lab

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2010 Sue Norwood and Jim O'Neil

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