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Most
people think it is too dry in the desert for amphibians,
but in fact, we have about 20 different kinds of desert
amphibians in the Mojave.
The
red-spotted toad is one of the most common. |
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reading for more information on this amazing Desert Survivor! |
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- Many
toads live
both on land and in the water. So when the water dries
up, if they're old enough, they can just live on land!
- In
the
winter months, when it's cold, they hang out
in burrows or under rocks, protected from the environment.
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- Many
toads slow down their body
functions, or metabolism,
so they don't need as much water or food. This way
they don't have to come out much until the weather
gets warmer!
- When
water is not available, the adults go hide in vegetation and
under rocks and only come out when it is cool, usually
after dark or during storms.
- Tadpoles
do not usually survive very long when the ponds
dry up.
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- In
the summer when it is really hot, adults, juveniles
and tadpoles will swim in water when it is available.
This allows them to stay cool and moist... and breath
in the case of the tadpoles!
- While
their are tadpoles in other parts of the world (mostly
in the tropics) they do not require pools of water,
all of the known Mojave Desert toads require standing
or flowing water to develop as tadpoles.
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The
differences between frogs and toads aren't as apparent as
originally thought. Traditionally in Europe,
toads were tetrapod amphibians,
without tails (other than a few two), that lived
primarily on land or in drier areas. Frogs, were considered
to be the smoother, more aquatic counterparts to toads.
Once
these distinctions were set, herpetologists started
to associate toads as warty, rougher skinned animals that
tended to walk more than hop. These classifications worked
fine until more species were
discovered and it was found that some frogs were actually
more like toads! With some new scientific methods, a few
other frogs and toads that were once considered to be in
one group, were actually more like the other!
Some
people have come to regard all anurans as
frogs and toads to be a group within anura called "bufonids".
Thus, all toads are frogs, but not all frogs are toads!
It may just be safer to call them all anurans! |
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- Adult
Length: 5-7.5 cm (2-3 inches) from snout to vent.
- Color: Brownish-green
with reddish-brown spots on dorsal side.
They
are short broad toads, with large parotid
glands behind their eyes. The parotid
glands are their only defense against predators,
producing and secreteing a
toxin that tastes bad and causes neurological effects.
Most animals will spit them out at the taste of the
toxin. Most animals don't need too many "tastes" to
learn to avoid them all together! |
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| The
red-spotted toad lives mostly in the Mojave
Desert (yellow to the right),
but is found in surrounding areas as well. The
red-spotted toad or Bufo punctatus, is
one of about 20 different types of anurans in
the American deserts! Desert
toads live in washes, streams, springs, temporary
pools, lakes, ponds, and even rivers. The red-spotted
toad tends to prefer rocky temporary pools called tinajas,
which means "wine container" in Spanish. |
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These
small temperary pools fill when it rains and evaporate between
storms. Tinajas
can be home to toads, shrimp, caddisflies,
aquatic beetles and plankton.
In just 11 days, this tinaja can
go from 60 cm (2 feet) deep, to completely dry!
Adult
toads tend to find shelter in vegetation,
under rocks and in abandoned burrows.
This behavior
keeps them cool in the summer, warm
in the winter, and hides them from predators that
would be more than happy to eat a little toad! |
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While
toads usually live near water, they are occasionally
seen hopping around as far
as 8 km (~5 miles) from water! It is not
clear how long they can survive that
far from water; we still have
much to learn about desert toads.
Desert
tadpoles
have no choice, they have to live in water. Unfortunately,
warmer water evaporates faster,
so ponds disappear faster in spring
and summer, when most toads lay eggs. Luckily,
like other ectotherms,
tadpoles develop faster in warmer water. As tadpole
body temperature increases so does their metabolism,
and development (aging). The
quicker a tadpole develops, the sooner it can live
on land! |
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| Adults
tend to eat insects, but are often willing to eat anything
that will fit in their mouths! Juveniles,
or tadpoles, tend to eat algae they suck off the water surface
or rocks and other features in the ponds. Like the adults, juveniles are
also notorious for devouring just about anything that will
fit in their little mouths. Another type of Desert toad,
from the genera Scaphiopus or Spea, have
actually been known to eat other tadpoles in situations where
resources become scarse! And you thought YOUR friends had big
mouths! |
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| Frogs
and toads are amphibians,
which means "double-life",
they spend part of their lives in the water and part on land.
Click on the pictures below to learn more about each developmental
stage. |
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spend their juvenile phase
in the water as tadpoles. They swim around in the water and
develop legs and lungs, and absorb their tail and gills as
they are no longer necessary. When they are mature enough,
they come out of the water and live on land. |
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| Here,
a researcher is collecting a water sample from a tadpole
pond to take back to the lab. The characteristics of
the water, such as mineral content and algae content,
tell scientists a lot about the diet and environment of
the animals that live in the water. Researchers will
also take temperature, pH,
salinity,
oxygen content, and a few other measurements at the pond.
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In
Dr. van Breukelen's lab (the lab of our Desert Survivors
Expert and where the hosts work), researchers are interested
in not only how the red-spotted toads' little bodies work,
but how they function under the stressful environmental pressures
of life in the desert. When researchers are interested in
how the ecosystem affects an organism's physiology, we
call this ecophysiology.
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Place
your cursor over
each question when you think you know the answer! |
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Dr.
Frank van Breukelen is an assistant professor at the University
of Nevada, Las Vegas. He received his PhD from the University
of Colorado, at Boulder. His research centers around
metabolic depression in response to environmental stress.
Squirrels, snails, toads, caddis flies, and sea monkeys are
just a few of the organisms Frank and his students study
in their lab. Frank is the primary investigator on the Desert
Survivors project and recipient of the NSF career award that
makes Desert Survivors possible.
Tune
in to Episode One to find out what makes desert animals
so special! Episode One highlights what a desert is and how
the Mojave
Desert was formed. |
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| Amphibians
& Reptiles -
A list of cool links you can explore! |
| Frogland -
lots of cool froggy stuff, but a little text intensive. |
| Amphibians
and Reptiles Scavenger Hunt -
Fun questions to answer with links to help you do the research! |
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