Scaphiopus couchii
Encyclopedia
Couch's Spadefoot Toad (Scaphiopus couchii) is a species
of North American spadefoot toad
. The epithet couchii is in honor of American naturalist Darius Nash Couch, who collected the first specimen while on a personal expedition to northern Mexico
to collect plant, mineral and animal specimens for the Smithsonian Institution
.
, northern Mexico
, and the Baja peninsula
. They can be found throughout the Sonoran Desert
, which includes parts of southern Arizona
and California
.
(Spea hammondii
) has a rounded "spade". Spadefoots are not true toads and should therefore simply be called spadefoots.
, and once the eggs hatch, water also provides a place for tadpoles
to mature to the adult stage. Because of the importance of water, spadefoots are active during the wet season (spring
and summer
in the northern hemisphere
), and remain underground during the dry season (fall and winter
). When a summer thunderstorm arrives, the male toads emerge from underground and look for pools of rainwater. When they find water, the males produce a mating call
that attracts female toads. Because the pools of water may be short-lived, mating occurs the first night after rainfall begins.
During reproduction, the male mounts the female and releases sperm
to fertilize the eggs, which are deposited in the pools of water in the form of a floating mass. The eggs hatch into tadpoles, which quickly mature into adult toadlets. They must reach the toadlet stage before the pool of water evaporates, and thus they sometimes mature in as little as nine days after the eggs are laid. Western spadefoot toads take longer to mature (at least three weeks).
The small pools of water are warmed by the sun
, which speeds up the growth of the tadpoles. Tadpoles will eat a variety of foods, such as small insects nearby the pool and algae
, which they scrape off rocks. They also filter microorganisms from the water as it is passed over their gills. Tadpoles gather in wriggling masses, stir up the muck on the bottom of the pool, and filter out the organic nutrients. Unlike most tadpoles, which are exclusively herbivores and filter feeders, spadefoot tadpoles are omnivores. They also eat dead insect
s and tadpoles, as well as fairy shrimp
.
Western spadefoots are known for more aggressive cannibalism
. If the pool is crowded and prey is abundant, a few of the tadpoles change into oversized, voracious carnivores which will eat other tadpoles. They prefer different species, but will eat their own if necessary for survival.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of North American spadefoot toad
American spadefoot toads
Scaphiopodidae is a family of American spadefoot toads. They are native to southern Canada and USA south to southern Mexico. Scaphiopodidae is a small family, comprising only seven species....
. The epithet couchii is in honor of American naturalist Darius Nash Couch, who collected the first specimen while on a personal expedition to northern Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
to collect plant, mineral and animal specimens for the Smithsonian Institution
Smithsonian Institution
The Smithsonian Institution is an educational and research institute and associated museum complex, administered and funded by the government of the United States and by funds from its endowment, contributions, and profits from its retail operations, concessions, licensing activities, and magazines...
.
Distribution
Couch's Spadefoot Toad is native to the southwestern United StatesUnited States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, northern Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
, and the Baja peninsula
Baja California Peninsula
The Baja California peninsula , is a peninsula in northwestern Mexico. Its land mass separates the Pacific Ocean from the Gulf of California. The Peninsula extends from Mexicali, Baja California in the north to Cabo San Lucas, Baja California Sur in the south.The total area of the Baja California...
. They can be found throughout the Sonoran Desert
Sonoran Desert
The Sonoran Desert is a North American desert which straddles part of the United States-Mexico border and covers large parts of the U.S. states of Arizona and California and the northwest Mexican states of Sonora, Baja California, and Baja California Sur. It is one of the largest and hottest...
, which includes parts of southern Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...
and California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
.
Physical description
Unlike other toads which have horizontal pupils, spadefoot toads have vertical pupils. On the underside of the hind foot, there is a hard, dark "spade" that gives spadefoot toads their name. These creatures can get to be 24" in length. These "spades" are used by the toads to burrow into the ground to prevent water loss and hide from predators. There are two spadefoot species in the Sonoran Desert of Arizona and California. Couch's Spadefoot toad (Scaphiopus couchi) has a sickleshaped "spade", whereas the Western spadefoot toadWestern Spadefoot Toad
Western Spadefoot or Western Spadefoot Toad is the common name of two different species of toads*Spea hammondii, found in North America*Pelobates cultripes, found in Europe...
(Spea hammondii
Spea hammondii
The Western Spadefoot Toad is a relatively smooth-skinned species of spadefoot toad. Its eyes are pale gold with vertical pupils. It has a green or grey dorsum often with skin tubercles tipped in orange, and it is a whitish color on the ventrum. It has a wedge-shaped black spade on each hind foot...
) has a rounded "spade". Spadefoots are not true toads and should therefore simply be called spadefoots.
Mating and reproduction
Water is a necessary medium for the fertilization of spadefoot eggsEgg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
, and once the eggs hatch, water also provides a place for tadpoles
Tadpoles
Tadpoles are a psychedelic rock band formed in 1990 in New York City by Todd Parker , Michael Kite Audino and Josh Bracken In 1992, Nick Kramer , David Max and Andrew Jackson of the fledgling Manhattan group, Hit, joined the Tadpoles after putting Hit on hiatus.In 1993 Kite and Jackson left the...
to mature to the adult stage. Because of the importance of water, spadefoots are active during the wet season (spring
Spring (season)
Spring is one of the four temperate seasons, the transition period between winter and summer. Spring and "springtime" refer to the season, and broadly to ideas of rebirth, renewal and regrowth. The specific definition of the exact timing of "spring" varies according to local climate, cultures and...
and summer
Summer
Summer is the warmest of the four temperate seasons, between spring and autumn. At the summer solstice, the days are longest and the nights are shortest, with day-length decreasing as the season progresses after the solstice...
in the northern hemisphere
Northern Hemisphere
The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...
), and remain underground during the dry season (fall and winter
Winter
Winter is the coldest season of the year in temperate climates, between autumn and spring. At the winter solstice, the days are shortest and the nights are longest, with days lengthening as the season progresses after the solstice.-Meteorology:...
). When a summer thunderstorm arrives, the male toads emerge from underground and look for pools of rainwater. When they find water, the males produce a mating call
Mating Call
Mating Call is an album by jazz musician Tadd Dameron issued in 1957 on Prestige Records, catalogue 7070. It was recorded at the studio of Rudy Van Gelder in Hackensack, New Jersey...
that attracts female toads. Because the pools of water may be short-lived, mating occurs the first night after rainfall begins.
During reproduction, the male mounts the female and releases sperm
Sperm
The term sperm is derived from the Greek word sperma and refers to the male reproductive cells. In the types of sexual reproduction known as anisogamy and oogamy, there is a marked difference in the size of the gametes with the smaller one being termed the "male" or sperm cell...
to fertilize the eggs, which are deposited in the pools of water in the form of a floating mass. The eggs hatch into tadpoles, which quickly mature into adult toadlets. They must reach the toadlet stage before the pool of water evaporates, and thus they sometimes mature in as little as nine days after the eggs are laid. Western spadefoot toads take longer to mature (at least three weeks).
The small pools of water are warmed by the sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
, which speeds up the growth of the tadpoles. Tadpoles will eat a variety of foods, such as small insects nearby the pool and algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
, which they scrape off rocks. They also filter microorganisms from the water as it is passed over their gills. Tadpoles gather in wriggling masses, stir up the muck on the bottom of the pool, and filter out the organic nutrients. Unlike most tadpoles, which are exclusively herbivores and filter feeders, spadefoot tadpoles are omnivores. They also eat dead insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s and tadpoles, as well as fairy shrimp
Fairy shrimp
Anostraca is one of the four orders of crustaceans in the class Branchiopoda; its members are also known as fairy shrimp. They are usually long . Most species have 20 body segments, bearing 11 pairs of leaf-like phyllopodia , and the body lacks a carapace...
.
Western spadefoots are known for more aggressive cannibalism
Cannibalism
Cannibalism is the act or practice of humans eating the flesh of other human beings. It is also called anthropophagy...
. If the pool is crowded and prey is abundant, a few of the tadpoles change into oversized, voracious carnivores which will eat other tadpoles. They prefer different species, but will eat their own if necessary for survival.