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Green and black poison dart frog. (Photo by R. Butler)
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OTHER GROUND ANIMALS
REPTILES
The most abundant vertebrate predators of the forest floor are reptiles, namely snakes and lizards. Best known of forest snakes are the giant constrictors, pythons of the Old World and Australasia, and boas of New World, but many of these are arboreal, aquatic, or relatively small. The majority of the snakes of the forest floor are small to medium sized, nocturnal, and mildly poisonous. They eat a range of amphibians, mammals, small birds, and insects. Very few of these species pose a threat to humans, although some are notorious for inflicting bites. The fer-de-lance viper of the New World, cobras of the Old World, and bushmaster of the New World are well-known examples.
There are several notable snakes of the rainforest with strange habits or characteristics. For example, the mole viper has long fangs that protrude beyond the corners of its mouth, while the African egg-eating snake, with its detachable jaw hinge, is specially adapted to feeding exclusively on bird eggs. This snake species is equipped with lower vertebrae that have an enamel-like coating and penetrate the esophagus to act as a saw-like structure. Although its head is about the size of a human finger, the African egg-eating snake can swallow eggs larger than that of a hen. One African snake species, sometimes labeled the "two-headed snake," has a tail that resembles its head, and a head that resembles a tail. In addition, to further confuse predators, the snake moves its tail in a manner that mimics the way most snakes move their heads. Thus if attacked, the tail (resembling the head) is the most likely target and the snake is much more likely to escape.
The komodo dragon of folklore would seem to be one of the largest, more formidable beasts on earth. However, in reality, many of the "facts" about the Komodo dragon are exaggerated. First of all, the komodo dragon is a lizard belonging to the group of 31 species of lizards known as monitors, found in the Old World. Secondly, the komodo dragon does not reach 30 feet (9 m) as reported by many, but the largest recorded specimen was just over 10 feet (3 m) in length—still an impressive size. The komodo dragon is found on a few scattered islands in Indonesia south of Celebes. With a belly full of deer, one may reach 500 pounds.
Chameleons, discussed in "Chapter 4: The Canopy" are actually most active near the ground. There are some 135 species of chameleons found in Africa, half of which are endemic to Madagascar (Malagasy chameleon pictures). These solitary lizards are well adapted to their surroundings with their well- known ability to change color, along with their large eyes which can be moved independently, and their meter-long tongue. Interestingly, chameleons often do not change color to match their surroundings, but instead to convey emotions, defend territories, and communicate with mates. At the height of the breeding season, colors are spectacular, as males try to impress females. At night, in a relaxed state, chameleons turn pale, almost white.
Another group of lizards from Madagascar is the fringed, leaf-tailed, or uroplatus geckos (pictures) which are incredible camouflage artists. Some species look exactly like bark, while others resemble moss when they flatten themselves against their surroundings. When discovered, uroplatus geckos respond by throwing their mouths wide open, showing the bright orange-red interior, and erecting their tails.
Amazonian Reptiles -
A Historical Account
Geckos are found worldwide and are quite famous for their abundance and loud call. Numerous species are kept widely as pets, while house geckos are found in virtually every house in the tropics, where they feed on house insects.
AMPHIBIANS
Amphibians are common on the forest floor, although not as abundant as those of the trees. Among the best known of rainforest amphibians are the tiny but brilliantly colored poison dart (arrow) frogs (members of the Dendrobatidae family). These striking but slow-moving frogs secrete powerful toxins from glands on their backs and use their color to advertise their toxic composition to potential predators. The potency of the toxin varies according to the species, and rainforest dwellers have been using these skin secretions for centuries to poison the tips of their blowdarts. The most toxic frog known is the yellow-gold Phyllobates terribilis, of Western Colombia, which is said to be fatal if held in the hand. Indians need only rub and arrow tip across the frog's back and the arrow is good for a year. Other poison arrow frogs must be roasted to extract their poison. The skin secretions of poison arrow frogs have human healthcare applications as evidenced by the story of Epipedobates tricolor and ABT-594/epidatidine.
Not all rainforest frogs are so brilliantly colored. In fact more amphibians take the opposite approach to defense: camouflage. Several species throughout the world, including the horned toad and two unrelated frogs in Brazil, look like dead leaves and when disturbed stretch out their back legs and become totally still for 30 minutes.
Amphibians are on the decline worldwide—more than 20 are known to have gone extinct this century. Several notable species including Costa Rica's Golden toad (Bufo periglenes) and the Gastric Brooding Frog (Rheobatrachus silus) of Queensland, Australia, have disappeared in recent decades. Scientists are puzzled over what is responsible for species loss among amphibians; some speculate that environmental degradation [habitat loss, climate change, increased UV levels from ozone depletion] has weakened populations to the point of making them more vulnerable to parasites, chytrid funges, ranavirus, and deformities. Because amphibians have highly permeable skin and spend a portion of their lives in water and on land, they are sensitive to environmental change and can act as the proverbial canary in a coal mine, indicating the relative health of an ecosystem.
A photo sampling of rainforest herps (reptiles and amphibians)
Panama golden frog (Atelopus zetecki)
Green and black poison dart frog (Dendrobates auratus)
Blue poison dart frog (Dendrobates azureus)
Yellow-Banded Poison Frog (Dendrobates leucomelas)
Dendrobates auratus poison-dart frog
Strawberry poison-dart frog in bromeliad
Green Poison Dar Frog, Costa Rica
Male Anole, Costa Rica
Rainbow Ameivas, Honduras
Agama Lizard, Thailand
Boa, Costa Rica
Blood Python (Python curtus)
Uroplatus fimbriatus gecko on Nosy Mangabe
Uroplatus fimbriatus gecko on Nosy Mangabe
Phelsuma quadriocellata gecko
Uroplatus fimbriatus gecko
Uroplatus phantasticus gecko
Uroplatus fimbriatus gecko
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Tree Frog, Thailand
Three-striped Poison dart frog (Epipedobates trivittatus)
Hyla tree frog close up
Monkey frog (Phyllomedusa bicolor) on forest floor
Unknown bright green lizard in the Peruvian Amazon
Amazon race runner (Ameiva ameiva) in Peru
Cnemidophorus deppei, Honduras
Monitor Lizard, Australia
Water Monitor, Thailand
Iguana
Emarld boa
Green Vine Snake (Oxybelis fulgidus)
Brookesia superciliaris chameleon in leaf litter
Peyrieras' Pygmy Chameleon (Brookesia peyrierasi)
Brookesia peyrierasi chameleon in hand
Furcifer balteatus chameleon
Calumma brevicornis (male)
Uroplatus fimbriatus gecko on Nosy Mangabe
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Acid Frog, Australia
Poison Dart Frog, Costa Rica
Mantella betsileo frog
Green Climbing Mantella (Mantella laevigata)
Gray frog in Isalo
Tomato frog
Frog of the Masoala peninsula
Uknown ground frog on Nosy Mangabe
Uknown leaf frog on Nosy Mangabe
Mantella madagascariensis (Painted Mantella)
Calumma parsonii cristifer
Calumma parsonii chameleon near Perinet
Calumma parsonii chameleon
Furcifer gastrotaenia chameleon
Furcifer verrucosus chameleon ready to eat insect
Furcifer verrucosus (green)
Furcifer pardalis chameleon
Furcifer pardalis (breeding coloration)
Brookesia superciliaris sleeping on leaf
Brookesia peyrierasi chameleon on twig
Brookesia peyrierasi chameleon on leaf
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Calumma globifer chameleon
Furcifer lateralis (juvenile)
Furcifer willsii (Female)
Furcifer willsii (Female)
Furcifer willsii (Male)
Uroplatus phantasticus
Phelsuma madagascariensis kochi
Phelsuma gecko near Maroantsetra
Uroplatus fimbriatus - dialated pupil
Uroplatus fimbriatus with flying insect
Uroplatus fimbriatus on trunk
Uroplatus fimbriatus - head shot tree trunk
Uroplatus fimbriatus - side angle head shot
Uroplatus fimbriatus - tree trunk, full body
Phelsuma Day Gecko, Nosy Mangabe
Uroplatus Gecko, Madagascar
Uroplatus Gecko, Madagascar
Phelsuma guttata Gecko in leaf
Phelsuma guttata Day Gecko on bamboo
Uroplatus fimbriatus gecko on Nosy Mangabe
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Review questions:
- Why are poison dart frogs colorful?
- Why are frogs endangered?
[print version | spanish | french | chinese | japanese]
Continued: Ground Invertebrates
Unless otherwise specified, this article was written by Rhett A. Butler [Bibliographic citation for this page]
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Recent news
Armageddon for amphibians? Frog-killing disease jumps Panama Canal
(10/12/2008) Chytridiomycosis — a fungal disease that is wiping out amphibians around the world — has jumped across the Panama Canal, report scientists writing in the journal EcoHealth. The news is a worrying development for Panama's rich biodiversity of amphibians east of the canal.
52% of amphibians, 35% of birds at risk from climate change
(10/8/2008) 52 percent of the amphibians, 35 percent of birds and 71 percent of reef-building coral are "particularly susceptible" to climate change, warns an IUCN report.
Good news for amphibians: three new species and one "extinct" frog discovered
(10/1/2008) Amphibians have received a lot of bleak news recently. Last week a report from the Zoological Society of London and EDGE stated that 50 percent of Europe’s amphibians will go extinct by 2050 unless more is done for their conservation. Meanwhile a report published in August found that one in three amphibians worldwide are threatened with extinction, while 200 species have already been lost since the 1980s. Therefore the discovery of three new frog species and the rediscovery of one thought to be extinct provide a little respite from such bad tidings.
More than half of Europe's amphibians face extinction by 2050
(9/28/2008) Researchers with the Zoological Society of London (ZSL) said over half of European amphibians face extinction in less than fifty years due to a perfect storm of threats: climate change, habitat loss, and disease. The announcement came at an event titled ‘Amphibians in a climate of change' hosted by Sir. David Attenborough, one of the world's most well-known wildlife enthusiasts due to his long career making nature documentaries.
Unknown but critically endangered iguana species discovered in Fiji
(9/19/2008) Researchers have discovered a third species of iguana in the Fiji. It is believed to be critically endangered, with a population of a "few hundred".
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