Turtles and Tortoises

There are 360 species of turtles and tortoises on our planet, and they all fall under the same family Order: Testudines. These reptiles are unique creatures with many fascinating features.

We will look at a few of the major similarities and differences between turtles and tortoises. Nomenclature for these animals varies among countries; we won’t go into that here.

The fundamental difference between turtles and tortoises is where they live–land or water–and how their bodies have evolved to accommodate their environment.

Some of the ways turtles and tortoises are alike: both are cold-blooded (like all reptiles), lay their eggs on land, and have air-breathing lungs.

Just like their lizard cousins, turtles and tortoises need the sun to thermoregulate. Many of us have witnessed this sight before.

The carapaces (shells) of turtles and tortoises differ somewhat. But for both, the carapace is a permanent body part, it is never shed.

There are many of Earth’s creatures that have carapaces: armadillos, shell fish, crabs, most mollusks, beetles, and more.

But turtles and tortoises are the only reptiles with a shell.

Derived from bone, the carapace is permanently connected to the spine and ribs. During development, the ribs grow sideways and enter the animal’s skin, and then develop into broad, flat plates. They form their own personal armor.

More info: Turtle Wikipedia and Tortoise Wikipedia

Interesting Chart showing common species of turtles, tortoises, and terrapins.

And a few of the ways turtles and tortoises differ….

A turtle’s carapace is relatively flat and thin to help with diving and swimming. Small turtles have feet that are webbed or clawed to aid in swimming and climbing onto rocks.

Large turtles have flippers, as you can see (below).

This turtle, below, doesn’t have a full, hard shell (like most). It is classified as a softshell turtle because the carapace is not fully bone. In the center it has a layer of bone, while the edges are made of cartilage and are leathery. It allows them to move more flexibly on muddy lake bottoms, and more quickly on land.

Sea turtles are one of my favorite creatures on earth. There are seven species in the world. In the U.S. we have six species and all are listed as endangered or threatened. Much work has been done to protect our big sea turtles, but there is still a lot left to do to ensure their survival.

Just like the smaller turtles, sea turtles live mostly in the water, coming to shore to bask in the sunshine and/or lay eggs in the sand.

Under water the sea turtles glide with beauty, ease and speed. They are omnivores and spend their submerged time foraging on sea grass, like this one below, as well as jellies and invertebrates.

But turtles breathe air and must surface at regular intervals to refill their lungs.

They labor on land, moving slowly and awkwardly. They use their flippers as best they can, but the earth is not water.

Sea turtles are about four feet long (1.2 m) and weigh up to 400 pounds (181 kg). They generally live about 80 years.

So turtles are omnivores and built to swim and flourish in the water.

Conversely, tortoises are strictly land creatures. They cannot swim.

Their carapaces are heavy and domed for protection against predators. Their legs are short and sturdy to accommodate the heft. Their feet are padded and stumpy, and the front legs are scaled to protect the tortoise while burrowing.

We found this gopher tortoise while visiting the Jacksonville Botanical Gardens. It was about the size of a dinner plate. We were surprised at how quickly it was moving because tortoises are generally very slow. Things to do.

There is dispute about how far back into the ages turtles and tortoises go. But it doesn’t take a scientist to look at their ancient faces and see they are very old creatures.

And that brings us to the longest living land animal in the world: the Giant Tortoise.

While many of the Giant Tortoise species are now extinct, we still have a few living species on remote islands in the Seychelles and Galapagos.

I was fortunate to visit the Charles Darwin Research Station on the Galapagos Islands, where they have a breeding program and conservation practices for the perpetuation of the Giant Tortoise. To date there are 16 separate populations on ten of the largest Galapagos Islands.

We spent the afternoon in the highlands of Santa Cruz Island (Galapagos), where we came upon several of these most mesmerizing and magnificent creatures.

They have an average lifespan of 90-100 years, though there are records of some living longer, up to 188 years. They are herbivores, foraging on grasses, cacti, and fruit; and move very, very slowly.

We patiently and appreciatively watched this Galapagos Tortoise on the trail. It took about 20 minutes for it to travel 60 feet (18 m).

They are the Granddaddy of all tortoises, some weighing up to 919 pounds (417 kg).

That day it was quiet in the highland forest, and the tortoises were docile. Except for one sound.

They can pull their heads into their carapaces, like many tortoises and turtles, and when they do the most astounding thing happens. This slow and quiet animal releases a loud hissing sound.

The hiss is the result of the individual releasing the air in its lungs to make room inside the shell for the head.

We came upon these three Galapagos Tortoises sleeping in the mud, while ducks paddled and frigatebirds circled overhead.

The sleeping tortoises looked like boulders.

Every few minutes, a frigatebird, one of Earth’s largest sea birds, would dip its bill into the pond and take a sip.

For more info about Turtle and Tortoises differences click here — Turtle vs. Tortoise.

Turtles and tortoises, several hundred different species on our planet. They use the sun to create their energy and walk through life with a shell on their back. That is one unusual and beautiful being.

Written by Jet Eliot.

All photos in the wild by Athena Alexander.

Lizard Land — Part 2 of 2

Green Iguana, Belize, native


Last week in Part 1 of this series we looked at lizards’ antipredator adaptations, camouflage, and size. Today we look at their skin, and various ways they move, sense, and communicate.


For starters, they are gloriously prehistoric. When you watch a lizard, especially the way it moves, it’s almost as if you are watching a dinosaur. The evolution of reptiles dates back 310-320 million years; more info here. 


Marine Iguana, Galapagos Islands


Blue-tongued Lizard pair, entwined, Sydney, Australia


Spiny-tailed Lizard, Ambergris Caye, Belize


Skin. Lizard skin is covered with overlapping scales made of keratin, providing protection from the environment. Scales also help prevent water loss, especially important in hot, dry deserts.


This photo shows the textured scales.

Western Fence Lizard, California


Tough and leathery, lizard skin is shed as the animal grows; they usually eat it for the minerals.


Locomotion.  Lizards live on the ground, in trees, rocks, underground, and even water. Therefore, they move in many different ways.


Although there are some legless lizards, most lizards are quadrupedal. Their gait has alternating movement of the right and left limbs, requiring the body to bend–shown in this photo of the Nile monitor.


Nile Monitor, Botswana, Africa


One of my favorite lizards for their movement is the common basilisk. When alarmed, basilisks rear up on their two hind legs and skitter across the water, earning them the name Jesus Christ Lizard. I’ve seen them run bipedally on the ground as well.


This photo demonstrates the basilisk’s muscular hind legs, necessary for bipedal locomotion.


Basilisk Lizard, Belize


Many species of lizards can effortlessly leap two and three times their body length. Lizards with short legs, like the skink, undulate like a snake.


Skink, California


Some lizards are extremely fast, while others, especially larger ones, are more languid. In addition, how much sun they have stored in their body is directly relational to speed.


The black spiny-tailed iguana (Ctenosaurus similis) is known as the fastest lizard, clocked at 21 mph (34 kph).


Black Spiny-tailed Iguana, Ambergris Caye, Belize


Geckos get the prize for hanging upside down. Their adhesive toe pads allow them to adhere to most surfaces.


The Asian House Gecko has the broadest distribution of any lizard in the world.


Asian House Gecko on the ceiling, Kakadu NP, Australia


Senses. With over 6,000 species of lizards, there are many variations of how lizards sense their environment–here are a few notable ways.


Eyes. Many lizard species, especially iguanas, have a parietal eye, a third eye, on the back of their head. It is photoreceptive and regulates circadian rhythm and hormone production for thermoregulation. Although it does not form images, it is sensitive to light and movement, helpful for detecting predators. The eye is difficult for us to see.


A chameleon can steer each eye in opposite directions. Geckos do not have eyelids, so they lick their eyes to keep them clean and moist. Geckos, like monitors, have acute vision.


Ears. Instead of external ears, lizards have ear holes or openings. The eardrums, or tympanic membranes, are just below the surface of the skin. These two close-ups clearly show the “ears.”


Dragon Lizard, Australia. Ear hole is reddish-brown circle below and left of eye.



This frill-necked lizard’s ear opening is just right of center photo, in an almost straight line below the eye. Australia.


Nose. All lizards, like snakes, have a specialized olfactory system for detecting pheromones or chemical signals. They have a vomeronasal organ (VNO), located in the soft tissue of the nasal septum. When you see a lizard sticking out its forked tongue, as in the photo below, what you are witnessing is the transferring of scent information from the tip of its forked tongue to the VNO.


Golden Tegu Lizard with forked tongue out, Trinidad


Mouth. Most lizards are predatory and hunt small invertebrates and/or insects. We have lizards to thank for keeping the insect population in check.


This western fence lizard had a fruitful day in my backyard. As winged nuptial ants were streaming from a rock fissure, he gorged for at least an hour.


Western Fence Lizard, California, eating nuptial ants. Notice all the dead winged ants he hasn’t yet had the chance to consume.


Here in California we are lucky to have the western fence lizard, because ticks that feed on this lizard do not spread Lyme disease. This lizard’s blood kills off the Lyme bacteria.


The marine iguana, found only in the Galapagos Islands, forages on algae, kelp and other marine plants. They will dive up to 98 feet (30 m), and can stay submerged for an hour.


While underwater, marine iguanas ingest salt. The salt is filtered from the blood and then nasally excreted. We saw many of them squirt salt out their nostrils.


This photo shows the marine iguana’s lovable face encrusted with algae (green) and dried salt (white) on it.


Marine Iguana, Galapagos Islands


As squamates, lizards have movable upper jaws, and some lizards, like the green iguana, have very sharp teeth capable of shredding leaves and even human skin. All lizards have teeth, dentition varies.


Communication. Lizards make sounds for courtship, territorial defense, and distress signals. Geckos are the most loquacious lizards, with chirps and squeaks that can be surprisingly loud. Sometimes you’ll hear a lizard hiss, a warning.


Other forms of communication include:  various body postures like push-ups and head-bobs, as well as the expansion of the dewlap. Tail-flicking is common in territorial disputes.


We found this dapper anole with a bright orange dewlap in a Texas swamp.


Green anole, Texas


This green iguana below, near a river in Costa Rica where it is native, was nearly five feet long (1.5 m) including the tail. An arboreal lizard, they hunt and bask in the trees and can easily break a fall with their hind legs.


This photo shows his crescent-shaped, uninflated dewlap under the neck. Dewlaps are muscle-controlled, and help regulate body temperature; also used in courtship and territorial displays.


Green Iguana, Costa Rica


Leaping Lizards Batman! They are the coolest animal on this planet!

Thanks for joining me in Lizard Land.


Written by Jet Eliot.

All photos in the wild, by Athena Alexander.


Great Basin Fence Lizard, Great Basin NP, Nevada


Western Skink

Western skink, Calif.

Western skink, Calif.

A lizard found on every continent except Antartica, there are more than 1,500 species of skinks.


Where I live in northern California, we have the western skink species, measuring 4-8 inches (10-12 cm) long, including the tail.


A common species, the western skink occurs in western U.S. and Canada, see map below.   More info here and here.


True to their lizard nature, they like to bask in the sun; and have an insectivorous diet including spiders, moths, beetles and other insects.


As experts at burrowing, they are not often seen.  With a long list of predators, Plestiodon skiltonianus are most safe underground, or under rocks and leaf litter.


When attacked, the skink can perform autotomy, i.e., self amputation, of the tail appendage.  This mechanism distracts the predator long enough for the skink to escape.  The tail continues wriggling while the rest of the reptile has escaped.  Eventually the tail will regenerate, though it is sometimes deformed.



Western skink, California

The western skink has an especially beautiful tail, an azure feature that is often described as “neon.”  As the skink ages, the color can fade.


Their movement more closely resembles a snake than a lizard, because their appendages are very short.  Winding and swift, they undulate across the earth in a speedy blur.


Arid summer days in California, where there is no humidity, produce dry leaf debris on our forest floors.  After the sun has been up for an hour or more, the reptiles begin their basking.


On my morning walks when I hear a soft rustle in the leaf debris, I always stop to see what will scurry out…hoping to see the dazzling blue of this shy and resplendent creature.


Plestiodon skiltonianus distribution.png

Plestiodon skiltonianus range map. Courtesy Wikipedia

Photo credit:  Athena Alexander



Western Rattlesnake, sub-species Northern Pacific; Calif.

Western Rattlesnake, sub-species Northern Pacific; Calif.

Halloween Week brings out the scaries, but once you read about rattlesnakes, goblins might induce more fear.


Native to the Americas, rattlesnakes hunt rodents, lizards, and insects; and prefer open, rocky habitat.  Rocks offer the viper protection, and open areas offer sun basking.


As an ectothermic vertebrate, the rattlesnake relies on the sun for heat and metabolic activity.  During cold weather, they lie dormant.  More rattlesnake info (with a rattling sound byte) here.


Western Rattlesnake

Under our front steps

I live in “rattlesnake country.”  After 14 years, I have never had a dangerous encounter.  I have been rattled at, however, and readily recognize their warning.  It sounds like a shaking dry gourd.


Each year when they shed their skin, a new rattle segment is added.  Rattle growth varies depending on food supply and growth rate, and some rattles can break off; it does not reflect the snake’s age.


In our front yard

In our front yard

Each rattle segment is hollow, and made of keratin.  There are muscles in the tail that shake the tip, causing the hollow segments to reverberate against each other–they fire on average 50 times per second.


Once I had a large bundle of weeds in my arms and couldn’t see down.  I was headed for the tarp.  Another time I was on the phone, came outside for better reception, and apparently woke the master.  The rattle is loud and distinct, says nothing but “Stay away!”


Rattlesnakes are venomous, but their bites are rarely fatal to humans.  The majority of rattlesnake bites (72%) occur to intoxicated young males; and about half the bites occurred when the person noticed, but did not heed, the warning.  Obtaining antivenom treatment within two hours results in 99% recovery.


Rattlesnakes are super creatures.   Number one, they keep our mouse population under control.  Number two, how many creatures can fold their fangs back when not in use?   In addition, they gather strength from the sun, detect thermal radiation in warm-blooded organisms, and rattle unmistakable warning at their enemy.  Wish I could do all that…well, except for eating mice.


Photo credit:  Athena Alexander


Frill-necked Lizard

Frill-necked Lizard, Queensland, AustraliaNamed for the skin around its neck, the frill-necked lizard can be found mostly in northern Australia and southern New Guinea.  The “frill” looks like a stylish neck cape most of the time, but when the lizard is alarmed or defensive, the neck flares up into a jagged, menacing ruff.


Usually you see the lizard as photographed here, with just a flap of skin near its neck.  To be honest, usually you don’t see it at all.  Chlamydosaurus kingii are arboreal lizards, and they don’t come out of the trees too often; and when they do, they blend right in.


A relatively large lizard, they are about 33 inches (85 cm) long, with half that length as the body, and half as the tail.  They eat insects and small vertebrates, and come out of the trees to eat.  More info here.  They’re really fast on the ground, often running on their two back legs.

Frill-necked Lizard, Queensland, Australia

Frill-necked Lizard, Queensland, Australia


The first time we saw one, we were driving to a remote park and came across something about a foot tall on the road.  It vanished when we got close, but it didn’t hop like a rabbit or kangaroo, or run like a dingo.  So we screeched to a stop, ran to where we saw it disappear, but never saw anything.  About a week later we were with an Australian guide, figured out from the guide’s description it had been this lizard.


The guide then took us to a forest filled with termite mounds, no humans anywhere.  At first we didn’t see any lizards until the guide prompted us, pointed them out.  Then we saw one on nearly every tree!


Frilled Lizard

Image: Lizard Lounge Wikia.com

It’s perfect that this fiery dragon-like lizard is just another unique creature in The Land Down Under.


Photo credit:  Athena Alexander except as noted

Alligator Lizard

Alligator Lizard, Northern California

Alligator Lizard, Northern California

When the spring temperatures start to warm, around April or May, we see the snakes and lizards coming out of hibernation.  But spring was early this year (drought), so it was a joy to come upon this alligator lizard while hiking in mid-March.


Alligator lizards are rare where I live, you might see one once in a summer, if at all.  Elgaria multicarinata multicarinata occupy a narrow range along the U.S. west coast.  They are medium-sized lizards usually at about 5-8 inches long.  Their diet primarily consists of crickets, millipedes, spiders, and other insects.   It is thought that their name “alligator” derives from the large head on an elongated body and their powerful jaws.


I used to be afraid of lizards.  But I realized when I moved to a rural property where lizards were leaping everywhere, that I had to change my attitude about lizards.  So I did.  And here is one of the many things that I now love about lizards:  many of them can dispense with their tail if necessary, including the alligator lizard.


If a snake or other predator catches the lizard, the lizard will detach its tail tip and escape.  The predator is left with only a few inches of tail, while the rest of the lizard has run to safety.  The abandoned tail tip flips and writhes for a few minutes, and then stops moving.  A new tail tip eventually grows back.  That’s got to be one of the coolest things a being can do.


Photo credit:  Athena Alexander

Discovering the Anole

Anole, Costa Rica

Green Anole, Costa Rica

The world of reptiles is a vast one.  In the lizard Order of Squamata alone, there are 7,000 species.  While birding in the jungles of Costa Rica, I came across a lizard species that was new to me:  the anole.


It is a common lizard, with 390 species in the genus Anolis, found primarily in North, Central and South America.  It’s pronounced a-NO-lee.


Our guided birding group was intimate, only seven of us, including a family from our small inn.  The parents photographed and birded, while their two teenage sons searched for reptiles.  We birders had plenty of exotic and colorful new birds to keep us busy and happy, but after a time I took an interest in the quiet activities of the two boys.


Anole, Costa Rica

Anole, Costa Rica

I come from rattlesnake country.  We leave rocks and logs alone.  So when I saw these two boys confidently rolling over rocks and digging in leaf debris, I was aghast.  But as the morning unfolded, the treasures the brothers shared were wonderfully enlightening.


They kept finding anoles everywhere.  A very small lizard that fit in the palm of one’s hand, of various colors and sizes.  More about the anole here.  These boys were experts at finding the reptiles, handling them, and treating them with love and respect.  (They found great frogs too, more about that from a previous post:  Poison Dart Frogs )


Green and Black Poison Dart Frog

Green and Black Poison Dart Frog

And now, when it’s cold enough that the rattlesnakes are still dormant, I find myself peeking under logs looking for newts and frogs.  It’s a big world under there!


Photo credit:  Athena Alexander