Category: Reptiles


Komodo Dragon

Komodo dragon, resting on a rock. Image taken at Woodland Park Zoo, Seattle.

Komodo dragons are crazy cool lizards, with no natural enemies. They’re only found on a few small islands in Indonesia and most of what we know about them we’ve only learned in the last 30 years. They are the largest living lizards in the world, averaging 150 lbs (68kg) and 8 ft. (2.4m) in length, though they’ve been known to grow as much as 300 lbs and 10 ft. in length. And actually, since they can eat 80% of their body weight in one sitting (!!), a male that just finished a large meal can be weighed at more than 550 pounds. This big lizard had big ancestors. Their largest ancestor was the Megalania prisca, which grew to over 23 ft and 1,400 pounds and was the largest venomous animal to have ever lived (as far as we know).

Sleeping Dragon

A resting Komodo dragon. Image taken at the Woodland Park Zoo, Seattle.

Predominantly ambush predators, these lizards can hunt animals 5 times larger than themselves and 15 times their weight, including deer and water buffalo.  Although they appear toothless, because their gums cover their teeth until they’re ready to bite, they have 60 inch-long teeth and deliver deeper and more damaging wounds than a crocodile. When they eat, their gums tear and bleed. The blood mixes with the saliva and makes a slime that allows them to swallow their food whole. Every part of the prey is eaten, even hooves, and it all gets dissolved in their strong stomach acids. The lizard may have to sleep for up to an entire week while its food digests after eating a big meal.

Sleepy Komodo Dragon

Resting Komodo dragon at the Woodland Park Zoo, Seattle.

Oh and they’re venomous. What’s that you say? No they’re not? You learned a long time ago that the Komodo dragon has bacteria in its mouth and it’s a bacterial infection that causes the slow, agonizing death of the prey? Yeah, so did I. It wasn’t until 2009 that scientists discovered that they are venomous. They have venom glands in their mouth and venom causes their prey to continuously bleed. They die from blood loss and infection.

Cutey Pie

Komodo dragon. Image taken at the Woodland Park Zoo, Seattle.

Nothing is safe from a Komodo dragon-not even Komodo dragons. They are cannibalistic, with healthy dragons eating the young, old or injured dragons. Young Komodo dragons make up about 10% of an adult dragon’s diet. For this reason, when young dragons hatch, they dash up into the trees to avoid being eaten. But many won’t make it. Birds, snakes and other Komodo dragons-sometimes even their mothers- will catch them before they can reach the safety of the tree. They have to be cautious and quick when they come down for water and sometimes they may roll around in feces to mask their odor from adults.

I see you

A Komodo dragon. Image taken at Los Angeles Zoo.

One reason why they eat their own young may be that they need to in order to reach their huge size. The young eat insects, and small lizards and mammals, but there are very few medium sized animals on the islands. Those that are there were introduced and so weren’t always around. Perhaps eating their own young gets them to the next size level where they can go after bigger animals.

adorable lizard

Komodo dragon resting on a big rock. Image taken at the Woodland Park Zoo, Seattle.

These predators have excellent senses. They have a forked 16-inch tongue that works like a snake’s tongue-flicking it out into the world, they can taste/smell with their tongue. They can find carrion more than 5 miles away. They are covered in hard scales, each one with a sensory plaque for increased sensitivity. On their face and feet, each scale has 3 or more sensory plaques, further heightening their sensitivity. They can see in color. We used to think they were deaf, but that was disproved by a zookeeper that trained one to come when it heard her voice. Now we know that they only hear sounds in the low range of pitches. They can even distinguish between different human voices.

I see you

A Komodo dragon checking us out. Image taken at the Los Angeles Zoo.

Male Komodo dragons are territorial. Females and young can inhabit their territory, but males are only allowed to pass through when the visitor is tracking prey. They will fight other males to breed, standing on their hind legs and balancing on their tales. After the loser falls, he will lie still while the winner scrapes his claws along the loser’s back and tail as a sign of dominance.

Females use their claws to dig egg chambers. Since Komodo dragons will raid each others’ nests, the mother dragon will dig mazes of false tunnels to confuse any would-be egg raiders.

dragon claws

Komodo dragon claws, front foot. Females use their claws to dig egg chambers. Males will scrape them across defeated Komodos. Image taken at Los Angels Zoo.

dragon claws

Front feet of the Komodo dragon.  Image taken at the Los Angeles Zoo.

back claws

Komodo dragon claws, hind leg. Image taken at the Los Angeles Zoo.

Females will also guard their nests for up to 3 months. She’ll leave once the rainy season hits, since the chances of her eggs being disturbed are substantially less.

In 2006, we discovered another surprising fact about Komodo dragon reproduction. The females can be parthenogenetic! In London’s Chester Zoo, a female produced 8 offspring without ever having met a male, giving us our first glimpse at this cool adaptation.

Komodo dragons can live 50 years in the wild and up to 9 months without water. They are strong swimmers, able to travel between islands and dive to depths of 15 feet.

Swim time

Time to cool off. A Komodo dragon about to take a swim. Image taken at the Los Angeles Zoo.

Komodo Swimming

Komodo dragon going for a swim. Image taken at the Los Angeles Zoo.

People in Komodo and Rinca take precautions to avoid attacks from Komodo dragons. They don’t wander into the forests or grasslands alone and they never antagonize or approach the dragons. They’ve also had a long-held belief that if they feed the old dragons that could no longer hunt, throwing them old deer heads and hides and fish heads and guts, it was sort of a peace offering and it kept them and their children safe from getting attacked. Younger dragons sometimes ate the food as well. There was only 1 human death recorded in 30 years (since records started) from 1965-1995.

However, in 1995 Komodo park authorities banned the feeding of Komodo dragons, which environmentalists thought would make them grow lazy and forget how to hunt themselves. They also outlawed the dogs, which are considered an invasive species, which have been used to keep the dragons out of the villages. Since these things have been put in place, several people have been killed by Komodo dragons since 2000 and some dragons have recently begun to enter school buildings and homes. That’s right. Imagine a giant 8-foot venomous lizard walking down your school hallway.

K. dragon

Komodo dragon. Image taken at the Los Angeles Zoo.

It may surprise you to know that King Kong was actually based on an expedition to collect Komodo dragons. The best trappers had extreme difficulty and the dragons were escaping. The movie producer Merian C. Cooper took the story and changed the giant lizard to an ape.

Komodo dragons appear in a few other movies as well. In The Freshman they used an Asian water monitor to be a “Komodo dragon.” In Komodo Dragon, the dragons are computer generated. It turns out that real Komodos don’t do well with handling.

You can also find cool Komodo dragon art, like this awesome statue that lives at the Woodland Park Zoo in Seattle, that kids are allowed to climb on.

Dragon statue

A Komodo dragon statue in Woodland Park Zoo, Seattle. There are brightly colored tiles along its back. Children are allowed to play on it.

Alright, one last cool tidbit on this really long post. At a Singapore Zoo, they’ve used acupuncture to treat a sick dragon. It’s thought to have been successful.

Have one last photo of these beautiful animals.

Komodo Dragon

Komodo dragon, clearly contemplating the meaning of life. Image taken at the Los Angeles Zoo.

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See You Later…

 

alligator

An up close shot of a baby alligator. Image taken at the San Francisco Zoo.

It’s hard to believe I’ve been writing this blog for so long and yet I haven’t written about alligators until today. There are so many cool and amazing things about alligators, a lot of which are adaptations that are so efficient, they have been around in some form for millions of years.

Take the little dots all over their face, which you can see on Lafayette, the alligator shown above. Those little dots can feel vibrations in the water. Obviously this can help them find moving food. But it may also play a role in courtship. When alligators are courting, the males will make a low bellowing sound and blow bubbles and the vibrations these actions make in the water can be felt by other alligators. When they’re courting, they’ll also rub each others backs. Here is a great video of alligators making their bellowing sounds. I know is sounds really ferocious, but this is not the sound to worry about. When an alligator is feeling threatened (and therefore can be dangerous, although very few people are attacked and killed by alligators), they make a hissing sound. Hiss=bad.

I will reiterate, alligators are really not usually aggressive. They are territorial, so you want to leave them their space, but they don’t usually see people as food. We’re too big. It’s crocodiles you gotta watch out for. So…how do you tell the difference? Well, where are you? If you are not in the Southeastern United States or in the Yangtze River in China then you are looking at a crocodile. But if you are in the south east of the U.S., then you can encounter both. Crocodiles are generally going to be much bigger, although a small crocodile and a large alligator will be very close. Crocs will have a narrower snout and at least two of their lower teeth will be visible when their mouth is closed. Alligators have a more rounded snout and their bottom teeth don’t show when their mouth is closed.

 

claude

Claude, an albino alligator. Notice his "U" shaped snout and the lack of visible bottom teeth. Image taken at the California Academy of Sciences.

Still, my advice is to not get close enough to check out their dentition.

So, humans are not really on the menu for alligators, but as opportunistic carnivores, they will eat just about any appropriate sized meat, including fish, turtles, birds and whatever else they can grab. But, if not eating them for dinner or feeling threatened by them, alligators can sometimes live closely with other animals without any danger. Claude (above) got along quite well with his snapping turtle tank mates. And this baby alligator is enjoying a turtle bed:

 

alligator and turtles

Alligator Lafayette using his turtle tank mates as a bed. Image taken at the San Francisco Zoo.

While we’re looking at a baby alligator, their is a lot to be said about how these little cuties come about. As reptiles go, the alligator mom is very attentive to her young. She starts by making a nest for them. She makes a nest out of decaying material and in the decaying process it gives off heat. In a sense she makes a natural incubator. Whether or not a young alligator is hatched a male or a female depends on the temperature (one of the concerns about climate change is that it will skew the ratio of males and females for animals with temperature dependent sex determination) they are incubated at. Since the ones at the center of the nest will typically be warmer than those at the outside, this usually leads to a pretty decent mix of males and females. When the young are ready to hatch, they will start making hatching calls that sound like a video game laser or a chirp. They make these sounds while they are still inside of their egg! The sound lets mom know that it’s time to unbury her nest and carry her little hatchlings to the water very gently in her mouth. She will care for her young for up to 2 years after they are hatched, which is very important since there are many predators for a young alligator, including other alligators. If a young alligator makes a distress call, the females in the area that have young will come to the aid of that youngster, whether it’s their young or not.

Lafayette and turtle

Lafayette on his turtle tank mate. Lest you think that the alligator is always on top, I have definitely observed turtles climbing over their alligator tank mates as well. Image taken at the San Francisco Zoo.

This young alligator was not even two years old when this picture was taken. For alligators, that is just a baby. They can live to be 65-80 years old in the care of a zoological facility and even in the wild they are very long lived. And they are survivors. Because they have low energy demands and relatively slow metabolisms they can even go up to 2 years without eating at all, just relying on the stores of fat in their tails. 2 years! These traits plus one other really cool adaptation also gives them the ability to hold their breath in warm water for up to 30 minutes. That other adaptation? Well it’s a little piece of their anatomy that is very special. They breathe and circulate blood pretty much just like we do. They breathe air into their lungs. Blood comes through the lungs to get oxygen and then gets pumped out to the body then back to the lungs, to the body, to the lungs and so on. But their 4 chambered heart (like ours and their relatives the birds but different from other reptiles) has a shunt in it that allows them to bypass their lungs entirely. They can keep recirculating their blood through their body and getting every last bit of oxygen out of it without it going to the lungs to refill. What a cool trick! In fact if you lower the water temperature, because they are cold blooded their metabolism drops even more. The record for an alligator staying under water, albeit in near freezing temperatures was 8 hours! 8 hours without breathing!

Their lungs are no less special than their heart shunt when it comes to assisting them in their aquatic lifestyle. Their lungs, filled with air, provide quite a lot of buoyancy. The alligators use this to their advantage. When they want to dive under the water, they can shift their lungs towards their tail. This lifts their lower regions up and dips their head downwards, giving them the first little dive they need. They can also shift their lungs from side to side, to allow them to roll. If anyone reading this was a fan of the crocodile hunter, you’ll remember him talking about the animal’s “death spiral.” That was achieved by moving their lungs around inside of their chest cavity.

 

albino alligator

Claude's rock is heated and he enjoys basking on it, especially after a big meal. Image taken at the California Academy of Sciences.

albino alligator and turtle

See I told ya. A turtle climbing on an alligator. Image taken at the California Academy of Sciences.

As well adapted as alligators are, there has been just one force of nature that almost proved to be too strong for them. Yup. You know it. Us. Believe it or not, there was a time when alligator skin purses, belts and boots were super fashionable-to the point where alligators were declared “endangered” even before the Endangered Species Act was passed. Fortunately, protections were put in place and alligator farms were established. These farms were allowed to operate as long as they released at least 25% of their alligators into the wild. With all of the protections in place, alligators flourished again and they are doing really well. Although, they certainly still have some human induced problems…the most interesting one being an introduction of non-native ginormous snakes, Burmese pythons, in Florida. Alligators can eat the young of these snakes but the adult snakes can take on alligators. The fascinating part about it is that alligators, when stressed, can lower their metabolism substantially and reduce their heart rate. When a snake is constricting, and the alligator drops its heart rate to just a few beats per minute, the snake assumes it’s dead and begins to swallow it. However, the alligators sometimes seem to come back from the dead and begin to fight the snakes from the inside out! There have actually been instances where the snake finished eating the alligator and it burst open from the inside! You can see a great video of a partially swallowed alligator fighting back here.

desert tortoise

A desert tortoise cruising around in the Mojave Desert.

This cutey is a desert tortoise, a beloved species that is the state reptile of both California and Nevada. I ran into this individual with my herpetology class in the Mojave Desert, near the Zzyzx desert station. It was my first ever glimpse of a wild tortoise! Despite the fact that they are large and slow moving (they “run” at between .13 and .3mph), I considered myself quite lucky to get a chance to spot one. Because of the harsh desert climate that can reach up to 140° F (!!), the desert tortoise survives by digging underground burrows to escape the incredible heat. And still, from November through February, it can get really cold, so the tortoises remain dormant and protect themselves from freezing by living in burrows. These things together means that these tortoises will spend 95% of their life in a burrow. So seeing one out and about was quite a privilege, though we increased our odds by  choosing a good time of day and season.

desert tortoise

This picture shows two important features of the desert tortoise-its gular horn and its long digging nails. Image taken in the Mojave Desert.

This picture shows two important features of the desert tortoise. Notice the long nails on its feet for digging those oh so important burrows I was talking about. But they dig for another reason too.  As they live in an environment that has very little rainfall, water is incredibly scarce. These tortoises get most of their water from the vegetation they eat. But, they have an extra trick to get some extra water-they dig catchment basins in the soil. They will remember the location of the basins that they created and can even be found waiting by them when rain is near!

The second feature is its gular horn, which is the part of its shell poking out from under its head. Both sexes have a gular horn, but it’s larger on the males. Males will use these to fight other males by trying to flip their opponent onto their back. The males will fight at any time of year and usually the fight ends with one of the tortoises running away. Despite their fighting, where there are burrows that can hold several individuals, the tortoises will share. As soon as they leave the burrow, the males will begin fighting again, but protection from the extreme heat is just too important.

Aside from the extreme climate, desert tortoises have another struggle. Getting enough calcium for those shells, which make up approximately 80% of their skeleton, can be very difficult. Although they are herbivores, because of their need for calcium, they will occasionally chew on bones to help meet that need.

I mentioned earlier that these animals are beloved and I was serious. They have some pretty powerful friends. In particular, Dianne Feinstein has a fondness for the tortoise (in fact one of the desert tortoises at the San Francisco Zoo has the middle name “Dianne Feinstein” as a recognition for all of her tortoise support). Desert tortoises are listed as threatened both federally and by the state of California and they played a key roll in the passage of the California Desert Protection Act in 1994, which has just been updated this year to include more protections, again specifically because of the desert tortoise. The reasons for their declining populations are many, including the usual culprits. They live a really long time (60-80 years in the wild, longer in captivity.) and they are late to reproduce. When they are younger, for the first few years they have a soft shell and predation is a major problem; in particular an increase in the raven population due to an increase of food from people’s garbage has led to an increase in predation on tortoises. But one of the worst problems to date has been problems with pets. People collect the tortoises as pets and when they don’t want them anymore or when they outlive the original owner some folks have thought it a wonderful idea to release the former pets into the wild. This has led to the spread of a horrible respiratory disease that has been fatal to many wild tortoises. These tortoises are not good pets and because of their protected status, it is illegal to collect a desert tortoise. So remember:

 

desert tortoise sign

This sign is a reminder that it is illegal to even touch a wild desert tortoise. Image taken at Zzyzx research station.

If you are lucky enough to come across a wild desert tortoise, don’t touch it! It is illegal and can be fatal to the tortoise. These tortoises store extra water in their bladders, which can still be used, but if they are scared, they will sometimes release this excess water, increasing their likelihood of dehydration. With all of the natural problems they have to face, the last thing they need is avoidable human caused problems.

Western fence lizard

A western fence lizard perched on my hand. Image taken in the San Francisco Bay Area.

If you enjoy hiking and live on the west coast of the United States, chances are you have come across this little lizard. This is a western fence lizard, which is also known as a “blue belly.” Blue belly is a good nickname for this lizard because…well, look:

Western fence lizard belly

A western fence lizard showing why they have earned the nickname "blue bellies." Image taken in the San Francisco Bay Area.

They do actually have blue bellies. The males are generally more blue than the females and will flatten to flash their blue when potential mates approach. When they are mating, some of the brownish scales will also turn bright blue. The only problem with the nickname blue belly is that there are a few species of lizard that have blue bellies, so it can get confusing.

Anyway, both female and male western fence lizards create a territory and they return to the same area year after year to reclaim it. This happens in the spring, which is a really good time to stop and watch them; this is when a lot of their interesting behaviors happen. While establishing their territory, they’ll posture and mark the area with chemical cues. Breeding males with do push-ups to try and attract females. If they succeed, they’ll bite the female’s neck and mate with her. If the female changes her mind however, she’ll flip over and use all four feet to kick the male off of her.

But aside from being entertaining, these little lizards that you see running around all of the time also provide a wonderful service for hikers, in what is probably the coolest animal fact I have uncovered since the photosynthesizing sea slug. Here’s what it does:

A tick on western fence lizard

A tick feeding on a western fence lizard. Image taken in the San Francisco Bay Area.

That lump on its neck is a tick. (Notice the lizard in the second picture has two, one on each side) The western black-legged tick is the main vector of Lyme disease for humans in our area. However, the blood of a western fence lizard has a protein in it that kills the bacteria that causes Lyme disease. If one of these ticks feasts on a western fence lizard, it becomes “disinfected.” If it had the offending bacteria, it no longer does and can no longer cause disease in humans! What’s more, these ticks, especially the nymphs, love to feast on fence lizards. The overall result? In areas that are not lucky enough to have these lizards around, about half of these ticks carry the Lyme disease causing bacteria. Where there are western fence lizards, that percentage drops to between 1 and 5%. Even if we get bitten by the right species of tick, the likelihood of getting the disease is really low.

When I find out about something as unlikely as this, it always reminds me that we are a part of an overall balance and cannot possibly know the effects of removing one species from it. So many factors like this crisscross in ways we have yet to uncover. Before the late ’90s, when this was discovered, who would have guessed that if the western fence lizards were to disappear, we could face an increase in cases of Lyme disease? Or that their blood would have a Lyme disease-bacteria-killing protein in it? And how awesome is that!

Anyway, thank you western fence lizard; your sacrifice is much appreciated.

Northern Pacific Rattlesnake

A Northern Pacific rattlesnake. Image taken at the California Academy of Sciences.

Rattlesnakes! Very common and very venomous snakes on the west coast and fascinating reptiles to learn about. Where to begin? I suppose the most common questions I’ve encountered about snakes have to do with their venom and the way they catch and kill food.

Humans are most likely to have problems with rattlesnakes when the snakes are feeling threatened and are defending themselves. Venom is actually very energy expensive to make and not beneficial to the snake to waste, so if a snake is aware of you and it can get away, it is likely to disappear before you’ve even noticed it. But, if you do cross a rattlesnake and it is threatened, usually it will give you a warning by shaking its rattle as a threat. Usually. Young rattlesnakes do not yet have a rattle, and the pieces or “beads” of its rattle will come with each shed. (You can’t actually tell how old a rattlesnake is by its rattle because pieces of the rattle can fall off and the number of sheds a snake has varies.)This fact is most unfortunate, because young rattlesnakes are actually more dangerous than adults. Adult rattlesnakes control the amount of venom they use to try to conserve it, whereas the young don’t hold back venom.

There is another reason why this warning is sometimes absent. Humans are selecting against it. Human fear of rattlesnakes often causes them to kill rattlesnakes when they are discovered. Therefore, the snakes that don’t make their presence known are the ones that are surviving and reproducing. Apparently, the number of rattlesnakes not giving this warning anymore is significantly increasing. So thank you, ignorant humans.

Northern pacific rattlesnake rattle

A Northern Pacific rattlesnake's rattle and its distinctive stripey tail. Image taken at the California Academy of Sciences.

In any case, usually a rattlesnake will rattle and hopefully the creature that stumbled too close respects the warning. If not, the rattlesnake will bite to defend itself. Sometimes the bites are “dry bites,” where the snake bites but does not inject venom. And sometimes they are not. The NIH has some excellent suggestions for how to avoid snake bites and what to do if you are unfortunate enough to get bitten here. My favorite piece of info gleaned from this site? Don’t pick up dead snakes because they can still bite up to an hour after death. ZOMBIE SNAKES!!! (Or a really strong biting reflex.)

So, venom and rattle are a great defense. So great that rattlesnakes even have non-venomous mimics. Gopher snakes have a similar coloration to some types of rattlesnakes and will shake their tail in dry leaves and hiss to mimic the sound and the appearance of a rattle. Rattlesnake defense is very important because far from being top predators, these animals are right in the middle of the food chain. Various birds of prey, especially red-tailed hawks are known to consume these snakes.

Venom does not always work as the best defense, however. Kingsnakes, for example, are immune to rattlesnake venom and will eat rattlesnakes. Ground squirrels are also immune to Northern Pacific rattlesnake venom and will exhibit mobbing behavior, aka ganging up on them. So these animals have a lot to worry about.

But, they are not always the victim. They are also the hunter. Awesome hunters. Rattlesnakes have an extra sense to help them hunt. Take a look at the image below. See the big circular spot under his eye, above his mouth?

Northern Pacific Rattlesnake

A Northern Pacific rattlesnake. Note the circular heat sensing pit. Image taken at the California Academy of Sciences.

This is a heat sensing pit. So, when you hold your hand over a stove, you can tell its hot without touching it right? Well imagine if that sense was so strong, you could feel the body heat of a furry creature at a distance. That’s what that pit does. So, even if the wind is blowing in the opposite direction and the snake can’t smell food, it can still find its prey. Neat, huh? And it uses its venom to hunt as well. This rattlesnake pictured here will bite its prey and let it go, but follow it until the animal stops running. The venom will actually partially digest the animal for the snake before it gets to it.

They’re not just great predators and great defenders, but the Northern Pacific rattlesnake is also one of the few snakes to exhibit any form of “parental care.” That is, young rattlesnakes are allowed to stay with their mother for a few weeks and gain protection from her presence. When its time to hibernate, they follow their mother’s scent trail to the same den year after year. Some of these dens have been occupied for over 100 years!

And one last way that these snakes might surprise you…they are actually great swimmers and have even been found several miles out to sea.

Michaela: The Red-eared Slider Turtle

Michaela

Baby Michaela, peeking out from her shell in the palm of my friend Nickie's hand.

Since I had pictures of my other furry and scaly family members posted under “Animals with their tongues out,” I thought it would be nice to also introduce my only female, Michaela. Michaela is a red-eared slider turtle.

Michaela

Grown up Michaela swimming around, shot from underneath her tank.

Michaela joined the family in mid 2004 and has grown quite a bit! I love this shot because you can see her pretty belly scales.

Like many reptiles, these turtles are frequently bought when they are really young and small and released when they get larger than the owner anticipated, or when the owner discovers how difficult they are to care for or how long they live. Red-eared sliders are not native here in California and are heavily competing with our only native pond turtle, the Western pond turtle. Western pond turtles are in serious decline right now, but that is mostly due to habitat destruction. Right now, zoos in California and Oregon are working with universities to collect Western pond turtle eggs, incubate and hatch them and care for the hatchlings until they reach a larger size, increasing their chances of survival, and then releasing them back into their habitat. They are also studying them to find out at what temperatures embryos develop into males and at what temperatures they develop into females (For many reptiles, incubation temperature plays a role in sex determination. Sometimes it’s the only factor, as far as we know). I am quite excited to see where this research leads and if they have much success in their “head start” program.

Alligator Snapping Turtles

Alligator Snapping Turtle

Alligator snapping turtle, mouth open. Image taken at the California Academy of Sciences.

Alligator snapping turtles are the largest freshwater turtles in North America. These creatures, which can weigh up to 250 pounds (there are unverified claims of finding some over 400 pounds), were nearly hunted to extinction for their meat, which used to be found in red and white cans on grocery store shelves (Campbell’s even made turtle soup).  This turtle shown above was one of several that was going to be made into turtle soup at a restaurant in the early ’70s until a biologist from the California Academy of Sciences found them and took them for their swamp exhibit instead. And what a wonderful addition they are. These slow moving, ancient-looking creatures are surprisingly graceful as they move about their home and coexist with their tank mate, Claude the albino alligator, quite well. Their other tank mates are not always so lucky because although they are well fed, well, they do sometimes eat the fish in the exhibit. But that is rare. During the early ’70s, over 3 tons of snapping turtle was caught every day, but thankfully now they are protected (by states, not federally). Hopefully they will be able to make a recovery just like the American alligators did.

These turtles are pretty sedentary animals. They only have to come up for breath every 40 minutes or so (again, here we are wasting precious energy and thus oxygen to keep our temperatures up! Oh to be an ectotherm!). At night they will actively hunt, but during the day they are ambush predators, so they will sit really still at the bottom of a river (adults, except for egg-laying females, spend their entire time in the water) waiting for food to come to them and algae will settle on their backs or grow on them, which helps with camouflage. But these sit-and-wait predators have an extra trick up their shell. Inside their mouth, at the end of their tongue they have a little appendage that look exactly like a worm.  And they will wiggle that little tongue around until an unsuspecting fish comes by looking for a snack and instead SNAP! And this SNAP is a very strong SNAP. It has been verified by researchers that this SNAP has cleanly severed fingers off.

So, these turtles are already pretty cool, but is there a way to make them even cuter? Why, yes. The juveniles have prehensile tails that may help stop them from being washed down stream by heavy currents.

For more info, the USGS has a few interesting tidbits and a wonderful list of sources for further research.

Bearded Dragon, Duke

A bearded dragon, Duke, enjoys the warm sun. Image taken at the San Francisco Zoo.

These friendly little lizards have an awesome temperament. It’s rare that I would recommend a herp as a pet, but if you can take care of them these lovely lizards are really fun to just hang out with, hence the title, lounge lizards.

This particular lizard shown above is Duke and he was the most awesome-est bearded dragon ever. My most memorable moment with him was when I was holding him for an “open house” at the San Francisco Zoo and he suddenly started to get squirmy, which was unusual for him. The guitarist from Green Day was enjoying our open house and he and some other folks came up to touch Duke and that was when Duke pooped in my hand. He did try to warn me first. Duke passed away not too long ago, and I really miss him. So this post is dedicated to my lost lizard friend, Duke.

Like many animals, bearded dragons have a plethora of ways to protect themselves from predators. The first is of course camouflage. Their coloration helps them to blend in, but it is also worth noting that their color changes for various reasons, including temperature control, as they get darker when they need to absorb more heat and lighter when they need to reflect heat. (And here we are wasting precious calories making our own heat! Ha!) If a beardie is spotted, the next thing it’ll do is try to intimidate a potential predator by puffing out the extra skin around its throat to make a big black beard and to make their soft spikes stick up to look sharp and threatening. If the predator is not fooled, the lizard still won’t give up- instead it’ll high-tail it out of there by getting up on its two hind legs and running. And last but not least, if the predator should catch the lizard by its tail, it can drop its tail and the nerve endings in the tail will make it twitch and hopefully keep the predator distracted while the rest of the lizard makes its getaway. This last defense though is a one time only tactic, as they don’t regenerate their tails like some other lizards will.

I also think its cool that bearded dragons communicate with each other using different gestures. If two bearded dragons are cruising along and they run into each other, one way they might say “hello, I’m the same species as you” is to walk up and lick each other.  They will sometimes wave one arm in big circles as well, which might also serve as a sign of submission. They are not usually aggressive towards each other (although they can have “ritualistic sparring matches.”) and so they can sometimes be housed together, allowing me to have the opportunity to take adorable pictures of them, like these:

Tully and Derby

Tully and Derby, bearded dragon brothers, making a lizard pile. Image taken at the San Francisco Zoo.

Tully and Derby again

More of Tully and Derby's lizard pile. Image taken at the San Francisco Zoo.

The Horned Lizards

Coast horned lizard

Coast horned lizard. Image taken at Zzyzx desert station.

Hello cute little lizard.  You’re so cute and tiny, yes you are.  What a sweet little creature.  How does such a tiny lizard protect himself in this great, big desert?  Well, I can see that you blend in really well to your habitat that’s got to help.  All of those pretty spines reduce your shadows as well.  And of course, you’re a master at being motionless to avoid attracting predators.  What about those horns?  Are they good for anything?  Oh you don’t say?  Apparently there have been snakes and birds found dead with a horned lizard’s spike in their throat.  Hmm.  Okay.  That’s a good weapon.  I suppose that’s it then.  That’s all you really need right?

Unless you’re one of the four species of horned lizard that aims and  shoots a steady stream of blood out of their eye, like the lizard pictured above.  That’s right, the stigmata defense.  In Mexico, they call these lizards “torito de la Virgen,” which means the Virgin’s little bull, because they have horns, and they weep tears of blood.  Apparently this blood is pretty foul too, as coyotes have been seen whimpering away and rubbing their mouth after getting shot at.

Okay little lizard, you are protected.  But how are you able to find food?  What is it you like to eat? Ants? But I thought ants are usually found in big groups and gather to protect themselves.  Oh they do.  They just can’t get past your body armor.  And your immune to ant venom.  Huh.  Way to go.

Actually, their diet of mostly ants is probably why they have evolved all of these amazing defenses. Because ants have a lot of chitin in them and chitin can’t be digested, the horned lizard has to eat a lot of them.  That’s why they have that wide, big, fat, belly-to store a lot of ants.

Horned lizard fat belly

Horned lizard from above. Note the wide body shape. Image taken at Zzyzx desert station.

However, it does make it a little harder to get around, so they need something other than ridiculous speed to protect themselves.  Hence the camouflage, armor, horns and blood squirting eyes.

Worst case scenario, they can always give you the evil eye.

Horned lizard, front view

Coast horned lizard, front view. Image taken at Zzyzx desert station.

One other thing I’d like to mention, one of the biggest problems facing these animals right now is collection for the pet trade, so if after this you still think they might make a good pet, please consider this.  Ants as food are very hard to come by, and the lizards have a really low survival rate in captivity.  And they might just squirt blood at you.

For more information on our adorable friends, check them out on the University of Texas website.