The Surinam Toad - A Strange Amphibian From South America
The Surinam toad lives in South America and is one of the strangest amphibians on Earth. It has a flattened body, a triangular head and tiny eyes. It also has one of the weirdest methods of reproduction of any amphibian.
Reproduction begins with the male and female toad performing an elegant mating swim. The female releases eggs, which the male fertilizes. He carefully places the fertilized eggs on the female’s back. The eggs then sink and become embedded in the female’s spongy skin. A honeycomb-like structure develops, with one egg in each chamber of the honeycomb. Skin grows over the eggs and they eventually disappear from view.
The eggs hatch inside the chambers. As the young toads grow they move around, creating a rippling appearance on the female’s back. Eventually the tiny toads break out of their chambers and escape into the world.
Scenes from a Captive Surinam Toad's Life
The Surinam, Suriname or Star-Fingered Toad
The Surinam toad (scientific name Pipa pipa) lives in the northern part of South America. It's named after the country of Suriname but lives in nearby countries, too.
The toad is most common in the Amazon basin. It inhabits tropical rain forests at low elevations and is found in murky ponds, swamps and slow-moving streams. It also lives in captivity around the world as a pet and a zoo animal.
The Surinam toad has a very strange, squished appearance that make it look as though it has been been involved in a nasty accident. Unlike other frogs and toads, the Surinam toad doesn't sit upright on its hind legs. It's constantly in a flattened posture.
The toad has a wide body with a triangular head and tiny black eyes that have no eyelids. Its nostrils are located at the end of tubular structures on its snout. The toad reaches a maximum length of about eight inches, not including the legs, but most individuals are four to six inches in length.
The long “fingers” on the toad's front legs have star-shaped structures at their tips, giving the animal the alternate name of star-fingered toad. The rays of the stars end in filaments. These filaments are very sensitive to touch. Unlike its front feet, the toad's hind feet are webbed. The back legs are strong and are used for propulsion, but the front legs are weaker.
The toad is grey or brown in colour. Its skin is covered with warty protuberances. In addition, small tentacle-like extensions project from the chin and the corners of the jaw. Some individuals have a dark grey line on their undersurface that extends from the middle of theIr throat to the end of their abdomen. ThIs line is known as a seam.
The toad’s mottled brown or grey colour, flat body and habit of lying motionless on the bottom of a pond or stream make it look like plant debris or a dead and decaying body. This is probably a very useful feature for disguising the toad in the wild, especially since it's often an ambush hunter.
Feeding a Captive Surinam Toad
The Life of a Surinam Toad
The Surinam toad is almost completely aquatic, although it does move over land if its watery habitat dries up or during heavy rains. It comes to the water surface every half hour or so to breathe air, but it can stay underwater for an hour or more.
The toad doesn’t have a tongue or teeth. It either probes sediments for food with its long and sensitive fingers or it waits to ambush its prey. It sweeps the prey into its mouth with its fingers or lunges at its prey with its mouth, using suction to ingest the food. The Surinam toad eats worms, insects, crustaceans and fish.
Like fish, the Surinam toad has a lateral line on each side of its body. This organ developed in fish as an adaptation to aquatic life and is sensitive to water motion. The lateral line helps the toad to detect the movement of other animals in the water and is probably a valuable tool for detecting prey.
Female Surinam Toad Carrying Her Eggs
Surinam toads mate under water. The male toad doesn’t croak. Instead, he makes clicking sounds to attract a mate. He produces these sounds by moving the hyoid bone in his throat. Once he has found a receptive female, the male climbs on to her back and wraps his front legs around her body in a process known as amplexus.
While joined together the pair swim through the water, gracefully somersaulting as they swim. They may stay attached for hours. The female is larger than the male and provides most of the propulsion with her hind legs. While the toads are both upside down during a somersault, the female releases eggs, which fall on to the male’s belly. The pair then move into their upright positions. The eggs drop on to the female’s back and the male fertilizes them.
After fertilization, the male gently sweeps up the eggs with his hind feet, their webs expanded to form a fan, and positions the eggs carefully on his mate’s back. The eggs stick to the female's back, although how they do this is a mystery. The eggs don't stick to the male, even when they are in contact with his body, and they don't stick to each other.
The egg laying and depositing processes are repeated multiple times. The female eventually ends up with 60 to 100 eggs on her back. Once all the eggs have been positioned, the male leaves the female, his job done.
The video below shows the paired swim during egg laying in the Sabana Surinam toad, which is a relative of the Surinam toad.
Make and Female Sabana Surinam Toads During Egg Laying
Surinam Toad Babies Emerging From Their Mother's Skin
Development of the Eggs
Over a period of about twenty four hours the eggs sink into the female’s skin, which swells up to surround them. A covering forms over the eggs and for a while the presence of the babies is hidden. The baby toads take three to four months to develop.
As the babies grow, their activity in the female's skin becomes more and more noticeable. Once the youngsters reach a certain size, the skin "bubbles" as the babies move.
Eventually the young toads emerge from their chambers, leaving holes in their mother's skin. They snap at food as soon as they're released. The female sheds her damaged skin after the babies leave and grows a new skin layer for the next breeding season.
A Close-up View of the Surinam Toad's Amazing Birth
Red List Categories
The Red List categories shown from left to right in the above diagram are as follows
- EX - Extinct
- EW - Extinct in the wild
- CR - Critically Endangered
- EN - Endangered
- VU - Vulnerable
- NT - Near Threatened
- LC - Least Concern
The Surinam toad population is not endangered, but some other members of its biological family, which is known as the Pipidae, are not so lucky.
The Myers' Surinam toad (Pipa myersi) has a similar reproductive method to its Pipa pipa relative. It lives in Panama and possibly in Columbia. It's threatened by habitat loss due to deforestation and by water pollution.
Some people worry that the Surinam toad population could run into trouble in some parts of its range. It's collected for the pet trade and is also facing habitat destruction due to logging and the clearance of land for agriculture. It may be sensitive to water pollution, too.
Overall, though, the Surinam toad population seems to be doing okay at the moment. The IUCN (International Union for Conservation of Nature) has established a Red List which classifies animals according to their nearness to extinction. The Surinam toad is currently classified in the "Least Concern" category of the Red List. Hopefully researchers will be able to learn more about this amazing animal.
© 2011 Linda Crampton
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