Museum of Nature
October 23, 2010
Frogs – A Chorus of Colours
again, I've decided to put some of the interesting facts in the page... in case you feel like learning a bit. (note that not all the photos have captions... I got tired of writing)
exhibit description:
May 22, 2010, to January 9, 2011
If you've never thought of frogs as beautiful, this exhibition will definitely change your mind.
Here's your chance to meet some of the most fascinating amphibians we know: delicate tree frogs, fat bullfrogs, bizarre horned frogs, giant toads, and the bright and beautiful dart poison frogs (many of which are now endangered).
Learn about their biology, natural history, role in human cultures and importance to ecosystems—the perils they face in a changing environment.
Live specimens are presented in re-created, detailed natural habitats, complete with plants, rock ledges and waterfalls.
You can also:
- check out a skeleton of the world's largest frog, the African goliath frog (it weighs up to 3 kg!)
- listen to frog calls
- watch videos of frogs in action
- perform a virtual frog dissection (without hurting any frogs)
- spin an old-fashioned zoetrope to see how a frog jumps
- test your frog IQ.
this way!
what is a frog anyway?
frogs, slamanders, and caecilians are modern amphibians. these part-time land animals have no hair or scales covering their skin and mostly lay eggs in water. frogs are the only amphibians without tails -- they also lack necks. most have short bodies, bulging eyes, and powerful legs. frogs are the most successful amphibians by far. there are over 5,260 species of frogs living on every continent except antartica!
borneo eared frog (polypedates otilophus)
class: amphibia
family: rhacophoridae
size: 7.5 to 10 cm
range: sumatra, borneo, and other indonesian islands
sticky fingers
the toes pads of most tree frogs are covered with tubular cells standing on end. these tiny bristles compress and bend under pressure., allowing the toe pad to "form-fit" over irregular surfaces. mucus on the tips of the bristles allows them to stick to almost anything. most tree frogs can climb straight up trees, cling to the undersides of leaves, or hang preposterouslt from a branch by one toe.
dart poison frogs
class: amphibia
family: dendrobaridae
size: 2 to 7 cm
range: central and south america
don't kiss these frogs
the most poisonous animal is not a snake or a spider. it's a beautiful little frog! most frogs produce skin toxins, but the dart poison frogs from central and south america are the most potent of all. the golden poison frog, called terribilis (teh terrible), is so toxic that even touching it can be dangerous. a single terribilis contains enough poison to kill 20,000 mice or 10 people. it is probably the most poisonous animal on earth.
samantha spotting all the frogs.
fire-bellied toad (bombina orientalis)
class: amphibia
family: bombinatoridae
size: 5 cm
range: korea, northeastern chinea, and southeastern russia.
flashers
fire-bellied toads use skin colour for protection. the skin on the toad's back is green and black, providing camouflage from above. when disturbed, the toad throws its legs into the air, revealing a bright orange "fire belly". if flashing these bright colours don't scare the predator, the toad has toxic skin secretions tha make it an unpalatable meal.
Waxy monkey frog (phyllomedusa sauvagii)
class: amphibia
family: hylidae
size: 5 to 7.5 cm
range: chaco desert of argentina, paraguay, and bolivia
Wax on, wax off
Most frogs like cool, moist places. Waxy monkey frogs like it hot. They seal in moisture by giving themselves a rubdown with a waxy substance secreted through skin glands. Climbing to an exposed perch, they draw in their arms and legs and sleep in the sun. they awaken and hunt at night when the air temperature and the rate of water loss are lower.
what are frogs worth?
frogs eat untold billions of insects each year making them economically valuable to agriculture. they also provide a critical food source for birds, fish, snakes, and other wildlife. but the most important contribution frogs make may be their role as environmental indicators. when pollution or other environmental changes affect a habitat, frogs are often the first casualties. these delicate creatures provide an early warning for endangered ecosystems.
project golden frog
an epidemic disease, called amphibian chytrid fungus, is killing amphibians on every continent where they are found. in 2001, scientists removed a group of panamanian golden forgs just before the disease reached their habitat. when the disease arrived, nearly all the wild frogs disappeared. project golden frog is an international cooperative. the rescued frogs are now part of a long-term captive breeding program.
thin skin
frogs don't just wear their skin, they drink and breath through it, too! many frogs even have a special drink patch on the underside of the body. like a giant lung, the thin, moist skin allows gases to pass through, helping the frog to breath. to keep the skin working well, frogs must stay clean and moist. they produce sticky mucus to prevent drying. most frogs shed the outer layer of skin by twisting and stretching -- they often eat the dead skin as it comes off.
american bullfrog (lithobates catesbeianus)
class: amphibia
family: ranidae
size: 9 to 20 cm
range: estern canada, eartern and central u.s.
green invaders
more than a century ago, american bullfrogs were introduced into the western united states in hopes that they could be farmed for food. although the farming efforts failed, the bullfrog adapted to man-made ponds and waterways and is now a threat to native species of fish, snakes, birds, and other frogs - some of them endangered.
pollywogs
most frogs and other amphibians hatch as fish-like larvae called tadpoles. tadpoles exist to eat and grow. they eventually transform into froglets - a process called metamorphosis. these soft globs of flesh provide tasty morsels for snakes, fish, birds and even other frogs. the tadpole stage can last for days or years, depending on the species and the weather.
tomato frog (dyscophys guineti)
class: amphibia
family: microhylidae
size: 5 to 10 cm
range: estern madagascar
pet trade
brightly coloured frogs are popular with pet owners and collectors. while many frogs are bred in captivity, over-collection of wild frogs is still a major problem. frogs that live on islands or in small populations are most at risk. tomato frogs have been given priority protection by international law.
mmmm... a bacon lettuce and tomato frod sandwich sounds good.
the frog skeleton is built for jumping. the long back legs unfold in an explosive burst of movememnt, and the short heavy bones of the front legs act as shock absorbers when landing.
the west african goliath frog can grow to 40 centimeters and weigh over 3 kilograms
the fading chorus
over the past 50 years scientists have recorded major declines in frog populations around the world. more than 100 species have vanished completely, many frog die-offs are the results of local human activity, but the rash of disappearances has also reached remote areas. is there a global cause? scientists continue to search for answers.
toad warts are clusters of special glands -- they are not contagious!
swamp symphonies
frogs were the first land animals with vocal cords and they have been singing for 180 million years. with its mouth closed, a frog pumps air back and forth across is vocal cords. many male frogs have vocal sacs -- pouches of skin that fill with air. these balloons resonate sounds like a megaphone, and some frog choruses can be heard from a kilometer and a half away.
chinese gliding frog (rhacophorus dennysi)
class: amphibia
family: rhacophoridae
size: up to 10 cm
range: southeastern china, myanamar, vietnam and loas.
there they are!
defying gravity
gliding frogs have enhanced webbing between their toes. when leaping between branches or escaping toward the ground, their toes spread, and the webbing stretches like the wing of a hang glider. although no frogs can truly fly, gliding frogs can soar and land gracefully from daunting heights. their winged feet allow them to bank and steer through the air, and adhesive toe pads help them stick where they land.
they almost don't look real.
christopher checks out a display that shows how frogs jump
what big ears
most frogs have excelent hearing, but cannot hear the highest or lowest sounds that humans hear. a frog's eardrum is on the outside of its body just behind the eye. the size of the eardrums and the distance bewteen them determine which sounds a frog hears best. to protect its sensitive ears, a frog may produce special vibrations in its body to partly block the sound of its own loud call.
smokey jungle frog (leptodactylus pentadactylus)
class: amphibia
family: leptodactylidae
size: up to 20 cm
range: southern central america and northern south america
frog legs
smokey jungle frogs are excellent jumpers, but their powerful thigh muscles often land them on human dinner plates. other large frogs throughout central and south america are also used in gourmet cooking, and some populations are suffering. one species from the caribbean island of dominica has been eaten to the brink of extinction. local people refer to these endangered frogs as "mountain chicken".
frog in our throats
since the dawn of humanity, frogs have been on our dinner plates, and they still provide an important food source for some developing countries. but in wealthy nations, frog legs have become a tendy delicacy. americans import more than half a million kilogrmas of frog legs each year. every day tons of wild frogs are cought and shipped to restaurants around the world, and wild populations cannot keep pace with the slaughter.
long-nosed horned frog (megophrys nasuta)
class: amphibia
family: megophryidae
size: 10 to 12.5 cm (female); male smaller
range: sumatra, borneo, indonesia, and malaya
make like a leaf
these secretive frogs are leaf mimics. the pointed nout, projections over the eyes, and ridged "veins" running down the back help them disappear among leaf litter on the forest floor. the frogs lie motionless and ambush unsuspecting prey, including insects, spiders, crabs, scorpions, lizards, and other frogs.
frog eyes
frog eyes come in a stunning range of colours and patterns. most frogs see well only at a distance, but they have excellent night vision and are very sensitive to movememtn. the bulging eyes of most frogs allow them to see in front, to the sides, and partially behind them. when a frog swallows food, it pulls it eyes down into the roof of its mouth. the eyes help push the food down its throat.
ornate horned frog (ceratophrys ornata)
class: amphibia
family: ceratophryidae
size: up to 18 cm
range: uruguay, brazil, and northern argentina
sit and wait predator
horned frogs have a voracious appetites, but they are not built for chasing down prey. they bury themselves in leaves or loose soil and pounce on small animlas that blunder by. when harassed by a human or other large animal, these fearless frogs lunge and snap their huge jaws. like little green bulldogs, they bite and hang on until pried loose.
hopping drugstores
frog skin is covered with a cocktail of protective toxins. some discourage predators; others prevent the growth of bacteria and fungi on the moist skin. some of these chemicals are nearly identical to those that regulate our muscles and nerves. and it's no coincidence. the frog's toxic arsenal evolved, in part, as a defense against mammals that eat them. because we share common ancestry with other mammals, many fro toxins are remarkably potent in the human body. some are being studied for use in human medicine.
amazon milk frog (trachycephalus resinifictrix)
class: amphibia
family: hylidae
size: up to 7.5 to 11.5cm
range: french guiana, brazil, ecuador, peruvian amazon.
frogs have been around for about 200 million years!
the cuban tree toad is probably the smallest. adults are less than 12 millimeters in length.
african bullfrog (pyxicephalus adspersus)
class: amphibia
family: pyxicephalidae
size: up to 20cm in diameter
range: most of sub-sharan africa
frog without a pond
some frogs live in dry savannahs and scorching deserts. they survive long dry periods by limiting water loss and hiding from heat. during this aestivation, many cover themselves in a cocoon of dead skin. others give themsleves a rubdown with a waxy secretion. but most desert frogs hide from heat by going underground -- sometimes for years. spadefoot toads are expert diggers. their shovel-like feet allow them to dig as much as 2 meters beneath the surface.
during dry periods, african bullfrogs cover themselves in up to 36 layers of dead skin.
this parchment-like cocoon reduces water loss by 50 percent.
during shedding, most frogs eat the dead skin as it comes off.
australian water holding frogs dig into desert soils and wait for rain. they can remain underground for years!
one cane toad can lay as many as 35,000 eggs in a single string.
amerindian blowgun
this blowgun was handmade by a tribal hunter in ecudaor sometime before 1960. he hunted with it for nearly forty years
smooth-sided toad (rhaebo guttatus)
class: amphibia
family: bufonidae
size: up to 23 cm
range: northern south america
toothless predators
most frog have short, pointed teeth for gripping prey. but "true toads" in the family bufonidae have no teeth at all. these bold predators catch prey with their sticky tongues and swallow it alive. some large toads eat almost anything they can fit in their mouths, including mice, birds, snakes, and other frogs.
our little biologists hard at work!
first, we need to cut open the frog...
then pin the skin down...
sam enjoyed disecting frogs
christopher was pretty good at it too!
from fins to four legs
some 365 million years ago, finned, aquatic animals evolved into tetrapods, the first four-legged vertebrates. over time this new animal group moved onto land and gave rise to mammals, reptiles (including birds), and amphibians. today, frogs and other amphibians live in all but the harshest land environments, but many remain tied to water for development of their eggs and tadpoles.
labratory frogs
clawed frogs make ideal lab animals. they are easy to raise, require little space, and are sensitive to environmental chages. the transparetn eggs of most frogs offer embryologists a chance to watch babies grow from single cells into wriggling tadpoles. scientist have used frogs to study muscle function, perform pregnancy tests, and experiment with cloning. the first frog was cloned 30 years before dolly the sheep.
menu generic photos of the grounds and building
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