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| description |
The Western Spadefoot is small and squat. Its
back is olive-brown or gray with dark blotches and little red
bumps. The skin on its back is mostly smooth, unlike that of the
warty Western Toad. The adult Spadefoot has a white belly. It
has eyes like a cat - the pupils are vertical, black, and
almond-shaped. The Spadefoot gets its name from the tiny black
shovels (spades) on its hind feet. It uses these shovels to dig
burrows in the ground. |
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| fun
facts |
The male Spadefoot makes a sound like a tiny
snore to call females to the breeding pool. On a quiet, windless
night a group of male Spadefoots can be heard almost a mile away. The
females are usually silent.
When injured or handled roughly, the Spadefoot
gives off a smell like roasted peanuts or garlic, which can
cause sneezing. |
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| life
cycle |
Spadefoots gather at vernal pools to breed in
early spring, after winter rains fill the pools. Females lay
several hundred eggs. The eggs are covered in clear jelly and
are laid in small clusters of thirty eggs or less. The egg
clusters are usually laid on plants, just below the surface of
the water. The eggs hatch in 3 or 4 days if the water is warm.
If the water is cooler, they eggs can take a week to hatch.
The newly hatched tadpoles stay close to the
egg cluster for the first few days. It takes them 5 to 6 weeks
to grow about two inches. After about 8 weeks the tadpoles
change into young Spadefoots. This change is called metamorphosis.
During metamorphosis a Spadefoot cannot eat. After
metamorphosis, a young Spadefoot is much smaller than the
tadpole from which it came. A Spadefoot takes about two years to
become an adult. An adult can live for several years.
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| ecology |
Western Spadefoots are only active on a few rainy
nights between October and March. On these nights, they leave
their burrows to travel to breeding pools and to hunt. Adults
eat mostly insects, especially beetles, moths, and moth larvae
(caterpillars). Adults do not have many predators because their
skin tastes nasty. Small mammals
sometimes eat Spadefoots that have been killed on roads, but
they leave the skin untouched. Bullfrogs, on the other hand,
have been known to swallow adult Spadefoots whole!
Unlike the adults, Spadefoot tadpoles are not
protected by skin poison. The tadpoles are eaten by Aquatic
Beetle larvae and other aquatic
insect larvae, California Tiger Salamander larvae, wading
birds and ducks. Spadefoot tadpoles are omnivores, which
means they eat both plants and animals. They eat detritus,
Bacteria, Protozoa, small crustaceans
and sometimes they even eat each other!
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| conservation |
Spadefoots are very picky about their habitat.
They only live in certain vernal pools and in some drinking
ponds used by cattle. Scientists do not understand why they
breed in some pools and not in others. When their breeding pools
are destroyed, they often have nowhere else to go. To protect
Spadefoots for the future, we will have to protect the vernal
pool grasslands where they live today. |
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| investigate |
Why do you think the biggest Western
Spadefoots come from pools where California Tiger Salamander
larvae are present? Talk to the California Tiger Salamander
specialist in your class to work on your answer. |
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| What's
in a name?
Spea, the
genus of the Western Spadefoot, means
"cave", which refers to its habit
of spending its adult life in burrows. |
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