Welcome to this week’s Friday Fiction Facts! Sciency things fiction-writers need to know.

American bullfrog (Lithobates catesbeianus) The largest frog in North America. Reaches a length of 8 inches.

American bullfrog (Lithobates catesbeianus) The largest frog in North America. Reaches a length of 8 inches. Photo: Brad Glorioso USGS

Last time I wrote about swamps, bogs, and other wetlands. This time, as I promised, I’m going to tell you about some of the confusing characters that might inhabit those wetlands.  These are animals that sort of look the same and may even act alike, but can’t necessarily be used interchangeably.

So let’s hop to it, starting with…

Frogs and Toads

The first thing to know is that, scientifically, toads are a kind of frog or Anuran.  Frogs and toads are both amphibians, lay eggs in water, and begin life as tadpoles.  Both are found almost world-wide.  Most hop, but a few walk or run instead. Some climb trees.

  • · Kingdom – Animalia
  • · Phylum – Chordata
  • · Subphylum – Verebrata
  • · Class – Amphibia
  • ·  Order – Anura  <— Frogs (includes all frogs and toads)

There is one family of Anurans which are considered true toads. These are Common or EuropeanToads.  However, other Anurans have been given the informal name “toad” based on popularly accepted, but unscientific, attributes.

Fowler's toad (Anaxyrus fowleri)  Photo: Brad Glorioso, USGS

Fowler’s toad (Anaxyrus fowleri) Photo: Brad Glorioso, USGS

Since these identifying characteristics do serve some purpose in differentiating toads from frogs, I’ll go over those them here, with the understanding that there are many exceptions to these informal rules.

Frogs : In general frogs are smooth, wet, mostly water-dwelling, and often colourful and/or with interesting markings. With the exception of tree frogs, you will usually find frogs in or near water. They are great swimmers and in a pond are often found basking on lily pads.

Toads: In general, toads are bumpy, “warty”, and have dry skin. They are primarily land-dwelling and may be found in gardens or in the forest. They do, however, lay their eggs in water so can swim and will be found in water during breeding season.  They are often less colourful than frogs, usually gray, brown, or tan.

FACT: You will not get warts from touching a toad. However, many have toxins in their skin, so don’t lick one.


Alligators and Crocodiles


American Crocodile (Nat Park Svc)

American Crocodile (Nat Park Svc)

Alligators and crocodiles are both members of the Order Crocodylia, a type of reptile.

  • Kingdom: Animalia
  • Phylum: Chordata
  • Class:     Reptilia
  • Clade:    Crocodylomorpha
  • Order:   Crocodylia
    • Family: Alligatoridae <- Alligators & Caimans
    • Family: Crocodylidae <- Crocodiles

For quick recognition, to differentiate between alligators and crocodiles look at their heads.


L) Crocodile R) Alligator (photos: Florida Fish & Wildlife)

Crocodiles have more narrow heads and long V-shaped snouts. Their upper and lower jaws are the same widths, so when they close their mouths, you get that classic toothy grin. Crocodiles tend to be more aggressive than alligators.  They prefer freshwater but can tolerate sea water because of a specialized gland used for filtering out salt. They are usually grey-green in colour.

Alligators have wide heads and short U-shaped snouts. An alligator’s upper jaw is wider than the lower jaw, so when its mouth is shut, the lower teeth slide into small depressions in the upper jaw so you see very few teeth.  Alligators prefer fresh water, and will inhabit, lakes, canals, swamps, or even a swimming pool!  They are usually black.

Alligator NASA

American Alligator (NASA)

FACT: There are only two species of true alligators: The American Alligator (A. mississippiensis) and the small  Chinese alligator A. sinensis of the Yangtze River. Chinese Alligators only grow to about 5 feet, whereas the American Alligator can exceed 15 feet in length and grow to over 1000 lbs.






Turtles and Tortoises

Red Eared Slider (Photo: Oregon Dept of F&W)

Red Eared Slider (Photo: Oregon Dept of F&W)

The relationship between turtles and tortoises is like that of frogs and toads.  Every reptile with a shell is considered to be a turtle so tortoises are a type of turtle.

  • Kingdom: Animalia
  • Phylum: Chordata
  • Class:     Reptilia
  • Clade:    Crocodylomorpha
  • Order:   Testudines (=Chelonii) <- All turtles
    • Sub-Order: Cryptodira <– Most living turtles & tortoises
    • Sub-Order: Pleurodira <- side-necked turtles
A desert tortoise emerges from its burrow. Arizona Game and Fish Department photo.

A desert tortoise emerges from its burrow. Arizona Game and Fish Department photo.

As a rule, land-dwelling turtles are called tortoises. Since our topic is creatures of wetlands, it is useful to know that there are no true tortoises in North America that would be found in a wetland.  They are all desert and grassland species.  Box turtles act more like tortoises (and in some countries are called tortoises) in that they are land-dwelling. Some species prefer grasslands. Others prefer forests.

Red Footed Tortoise egg (Smithsonian / Nat Zoo)

Red Footed Tortoise egg (Smithsonian / Nat Zoo)

However, there are dozens of species of turtles which inhabit ponds, swamps, lakes and rivers in North America. These include snapping turtles, sliders, mud turtles, map turtles, and painted turtles, among others.

FACT: The sex of baby turtles is determined by the temperature of the eggs during incubation. The difference between a temperature that creates females and one that creates males may be just a few degrees (the ideal nest resulting in both sexes, depending on the depth of the eggs.) This has implications when it comes to climate change as warming temperatures may cause some species to create nests of same-sex offspring year after year.