Frogs and toads belong to the Order
Salientia. Within that order we find the following frog and toad
families represented in North America north of Mexico:
COMMONLY ENCOUNTERED FAMILIES
- True Frog Family -- Ranidae:
throughout
- Treefrog Family -- Hylidae:
throughout except parts of the West
- Toad Family -- Bufonidae:
throughout
UNCOMMONLY
ENCOUNTERED FAMILIES
- Narrow-mouthed Frog Family -- Microhylidae:
mostly southern US
- Burrowing Toad Family -- Rhinophrynidae:
southern Texas
- Spadefoot Toad Family -- Pelobatidae:
most of US
- Leptodactylid Frog Family -- Leptodactylidae:
Florida & Texas US
- Tongueless Frog Family -- Pipidae:
introduced into southern California
- Tailed Frog Family -- Ascaphidae:
in northwestern US & southwestern Canada
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TRUE FROGS
What's the difference between a frog and a toad?
The easiest-to-see distinction is that toads have warty skin, while frog skin is
relatively smooth. That's a Bullfrog at the right, so you can see
that its skin isn't nearly as warty as the toad at the bottom of this page.
One way to decide whether a backyard frog belongs to the "True Frog Family"
is by the process of elimination. The vast majority of backyard naturalists will very
seldom or never see members of families listed above as "uncommonly
encountered." Most of those families are found in restricted geographical areas, or
else -- as in the case of spadefoot toads -- the toads may be present, but very secretive.
Therefore, if you learn to identify treefrogs and toads and decide that your critter is
neither of those, then just about every other froggy creature you find will be a
"true frog," a member of the Ranidae.
TREEFROGS
The frog at the right can be recognized as
belonging to the Treefrog Family because of its small size (up to 2.5
inches long -- 7 cm). Also, its feet bear conspicuous rounded pads at the tips of its
toes. Those pads are adhesive pads enabling them to, among other things, stick to the
vertical aluminum siding of my trailer! This particular little beauty is the Barking
Treefrog, Hyla gratiosa, of the southeastern US. Its mating call is a
single, bell-like note, but sometimes it also gives loud, barking "rain-calls"
from high in the trees. A few treefrogs, such as the cricket frogs (genus Acris)
have toes without pads.
At the
left you see a Pacific Treefrog, Hyla regilla, crouching on a
leaf about six inches above the water of a small backyard pond. If you spot a treefrog,
he'll probably be crouched just like this one -- so that his diagnostic toe pads will be
hidden! One treefrog feature this particular frog can't hide is its small size.
It is less than two inches long. Most "true frogs" are much larger, and probably
they wouldn't be adhering to and crouching on a leaf surface like this.
TOADS
The two most conspicuous features indicating that the
individual at the left is a toad, and a member of the Toad Family, are:
Those "growths," one of which is barely visible
in the picture just to the right of the eye looking at you, are parotoid glands.
These glands secrete a viscous, white poison which gets smeared in the mouth of any animal
that might want to eat the toad. This poison inflames the mouth and throat, causes nausea
and irregular heartbeat, and rarely even death!
There's more about toads on our Toad Page. |