Food chains link the creatures of coastal ecology

Don’t stick your hand in that shell! You don’t know who might be home. It could be a carnivorous snail or a “clawsome” crab. Take a look at our Texas state shell, the lightning whelk or left-handed whelk, which feeds on bivalves like oysters and clams. Perhaps the snail that makes the shell is still hiding inside, or perhaps the shell is home to a hermit crab. Unlike most crabs, hermit crabs use the shells of snails as homes to protect their soft bodies.

Hermit Crab

Hermit crab taking residence in an empty lightning whelk shell.

Texas is home to some fascinating creatures, and our coast is no exception. In addition to the Gulf side beaches, there are salt marshes, jetties and the bay to investigate. Our coastal habitats are just waiting to be explored, and with the right gear, you can see organisms at every trophic level. (You knew I was going to talk about food chains, didn’t you?) 


Lightning whelk snail retracted into its shell, operculum blocking the opening.

Most folks will notice some of the upper-level consumers: birds like pelicans and gulls. Who could miss the gull snatching your unattended hotdogs? Or the pelicans plummeting into the water face first to catch fish? Maybe you’ve noticed fishermen along the beach as they pull in small bonnethead sharks. Some animals may require good timing and tons of mosquito repellent to see, like our rare and critically endangered Kemp’s ridley sea turtle. If you pay attention, there are even rattlesnakes catching mice that are feeding on insects and plants in the dunes!Food Web

As you follow a food pyramid from the apex down to the base, top predators like humans and sharks feed on the organisms in the level below. There you might find the larger bony fish we feed on, like redfish or snapper, and below them you can find some of the crustaceans and mollusks they feed on in turn. Crustaceans, like our blue crabs, stone crabs, and the smaller ghost crabs, often scavenge in addition to feeding on mollusks, worms, or even plant matter. Many of our mollusks are filter feeders, like oysters, pulling algae and plankton from the water. Finally, at the base of the food pyramid, there are the producers. The phytoplankton and algae make their own food with energy from the sun.

A food chain pyramid is a great way to show different types of food chains on one example. I used a pyramid created by my friend Julia and drew examples of food chains from our coast on it. One side has the trophic levels on it and the other three sides have example food chains. What’s on the bottom of the pyramid? The Sun, of course!Pyramid

Coastal ecology isn’t just about sand, shells, and dodging gulls. It’s also about the interactions between plants, animals, and their environment. The plants anchor the dunes, the dunes protect and replenish the beach sand, the sand houses animals like mole crabs and mantis shrimp, and we get to enjoy it when we protect it.

If tracking home beach sand in your shoes, car, towels, and suits doesn’t excite you, our new Hamman Hall of Coastal Ecology may be just the air-conditioned trip to the coast you need on a scorching summer day in Texas. Members, come join us Memorial Day weekend to see wonders of the Texas coastline!

Tales from Tanzania: Oh, the things you’ll find in a caldera

On the next leg of our trip, we visited the Ngorongoro Conservation Area.

NgorongoroNow, you may ask, “Nicole, your last adventure was in a national park, and this is a conservation area — what’s the difference?” And I’d answer that a conservation area has people living on it, whereas in a national park, no permanent settlements are allowed. The Maasi people live in the Ngorongoro Conservation Area with their cattle full time. They have been allowed this exception since they do not hunt. According to their traditional customs, they are only allowed to eat cow, goat and sheep so the wild animals in the crater have nothing to fear from them.

The Ngorongoro Conservation Area is especially interesting, as it contains the largest unbroken caldera in the world. It was created by a volcano, which has now collapsed. Before it collapsed, the volcano would have been much, much higher than Kilimanjaro.

The formation of a caldera

The crater has given rise to a variety of ecosystems due to its geography and sheer size. Moisture is pushed in from the ocean in the east, but it gets caught at the rim of the crater. The outside eastern edge of the crater, therefore, is home to a thick highland forest full of tropical birds. The west side of the crater only gets rain in the rainy season and most of the time looks something like dry west Texas.

Interestingly, the crater is responsible for most of what we have seen and what we will be seeing on this trip. The eastern edge of the crater is so dense that natural springs flow into Lake Manyara rather than the crater, keeping it green and providing a source of water for animals.

Looking to the west, when the volcano erupted 2.5 million years ago, the wind blew the volcanic ash to the Serengeti, which caused hard-packed earth that only the acacia can penetrate.

Later in the evening, we were able to talk to crater naturalist, Yotham, at our hotel. He was very surprised to see several of our pictures (we always knew we were looking at something awesome if one of the driver guides took out a cell phone to take a picture).

In particular, Yotham was surprised to see our shots of the Little Bee Eater, as they usually don’t come into the crater. Instead, they live in the highland forests on the outside western edge.

DSCN1517DSCN1205As we continued to go through our shots, he indicated that we had, in fact, had a very, very good day of observations.

Here are some of the highlights: 

Hyena kill: We arrived right after the wildebeest was taken down. Just out of screen are several other hyenas and 20 or so vultures waiting for their turn at the carcass. The eating hyena kept dragging the carcass away so it could eat without feeling crowded.

DSCN1604Ostrich: So, I learned something new today. When you see a male ostrich with a bright pink neck, it is feeling frisky. A male ostrich with a white or gray neck is not currently interested. Female ostriches are very beautiful but very differently colored than the male ostriches.

DSCN2036DSCN2048Serval: This picture is a bit miraculous. The serval is normally a nocturnal animal, so it was amazing to see it out during the day. AND THEN IT STARTED HUNTING. AND IT WAS AWESOME.


Tales from Tanzania: Witnessing the resiliency of nature at Lake Manyara National Park

Our first game drive through the 285 square miles (460 km2) of Lake Manyara National Park did not disappoint. Covering 89 square miles (231 km2) of the park, Lake Manyara is a salt lake ranging from 20 to 50 feet deep. The lake’s high alkalinity comes from sodium bicarbonate, which leaches out of the volcanic rock in which it sits.

When we arrived, the surrounding area had recently flooded, causing serious changes to the landscape in several ways. The most drastic had come from landslides so powerful they had nearly covered the original ranger office.

When the area flooded, the level of the lake also rose, causing the surrounding area to have significant deposits of sodium bicarbonate. This sudden change killed all of the trees in the flood area.

However, by the time of our visit we were able to witness the incredible resiliency of nature, as the area had already started to heal itself. This is helped by the many underground springs which bring in fresh water, giving the animals clean drinking water and clearing out the salt deposits. The grass is already making a comeback and the rangers are confident that the trees will soon follow.

While the flooding was terrible in so many ways, it might have done the area good, as it gets very little rain. Each year 75 percent of the lake evaporates in the dry season, which concentrates the salts. Hopefully the floods diluted the salts, if only for a short period. And as you can see in the following pictures, the animals hardly seem to have minded the flooding.


The baboons in Africa amazed me. As far as I can tell, they are the equivalent of a diurnal raccoon in the states. They are smart, quick on the uptake, like eating leftovers, and aren’t afraid to come take something that is shiny or smells good. We didn’t have any troubles with them, but we were warned not to feed them and were told tales of cameras and other treasures lost to the unsuspecting.


The second coolest things we saw that day was a Verreaux’s Eagle Owl with a fresh kill in its talons. It was surprising to see a diurnal owl here as most of ours are nocturnal.


Being part of the science dork crew from the Museum, the coolest thing I think we saw that day was a hippo carcass. I was in a truck with a large animal vet that day, Mary Sue, so we spent a good bit of time trying to CSI the hippo. A clear indication that large predators are in the area, the hippo carcass was picked clean — except for the skin, which was too thick for anyone to eat.

Tales from Tanzania: The banks of the Nile that divide two crocodiles

In a previous post, I mentioned that beetles are my favorite invertebrates — which sort of begs the question, “What’s your favorite vertebrate?” And that’s an easy one: Alligator mississippiensis or the American alligator. I am lucky that we live in Houston, close to alligators, and even luckier that we have a juvenile alligator in our live animal collection.

For now though, I am super excited to see a Nile crocodile. I have been assured that we will get a look at one today, as we travel through the Grumeti River area in the Western Corridor of the Serengeti National Park.

nile_crocodileUntil about two years ago the number of crocodilian species numbered 23. Was a new species discovered? The answer is kinda, but not really. Modern science proved what the ancient Egyptians already knew: The “Nile crocodile” is actually two species: the Eastern Nile crocodile (Crocodylus niloticus) and the Western Nile crocodile (Crocodylus suchus). The smaller, more docile Western Nile crocodile was commonly used in Egyptian culture (mummified, kept at temples, etc.) while evidence shows that Egyptians knew the larger, more aggressive Eastern Nile crocodile was to be avoided. DNA evidence comparing living crocodile populations and mummified crocodiles proved the distinct difference in the two species and brought the total number of crocodilians up to 24, of which nine are currently threatened or endangered.

What’s more, the same DNA study also showed that the Eastern Nile crocodile was more closely related to four species in the Caribbean than it was its neighbor, the Western Nile crocodile.

The Eastern Nile crocodile is the second largest extant reptile in the world. The largest accurately recorded male was shot in Tanzania and measured 21 feet, 3 inches and weighed approximately 2,400 pounds. In fact, we are visiting Tanzania at the perfect time to get a glimpse of these ambush predators as it is the dry season and they will be nesting.

I don’t want to get too close, however, as 63 percent of the 250 to 750 Nile crocodile attacks on humans per year prove fatal!

Bonus fact: A group of crocodiles is called a bask.