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Saltwater Crocodile (Crocodylus porosus)

Saltwater Crocodile
photo by flickr user fvanrenterghem

Common Name: Saltwater Crocodile or Salties
Scientific Name: Crocodylus porosus
Family: Crocodylidae – Crocodile family
Locations: Australia, Bangladesh, Brunei, Cambodia, East Timor, India, Indonesia, Malaysia, Myanmar, Palau, Papua New Guinea, Philippines,, Singapore, Solomon Islands, Sri Lanka, Thailand, Vanuatu, and Vietnam
Size: 17 – 23 feet (5.1 – 7 meters)

The Saltwater Crocodile is the largest living crocodile species in the world. These crocodiles can reach 23 feet and over 2,200 pounds! They received their name due to their resistance to saltwater. Most crocodiles only enter the saltwater in emergencies while the Saltwater Crocodile just lives there. They are capable of living over 70 years in the wild and longer in captivity.

Saltwater Crocodile Reproduction

The Saltwater Crocodile breeds during the wet season when the water levels are the highest. The females select a nesting site where she and a male eventually mates. The male is a dead beat dad and doesn’t provide any care for his offspring. He leaves the mom and tries to find more potential mates. The female crocodile shows a high amount of parental care.

The mother guards her nest of eggs, even splashing water on the eggs to help prevent them from drying up. The eggs take 3 months to hatch. The sex of the offspring depend on the incubation temperature. Temperatures below 86 ºF (30 ºC) result in females. Meanwhile, temperatures above 89 ºF (32 ºC) results in male offspring. Once the eggs hatch, the female digs out the babies and carries them to the water in her mouth. Then, she protects the babies until they are able to take care of themselves. What a mom!

Conservation

The International Union for the Conservation of Nature (IUCN) Red List categorizes the Saltwater Crocodile as Least Concern for Extinction. They have a fairly large range but the destruction of potential nesting sites is a concern. Another threat is hunting of the crocs for their pelts and meat. These threats are rather low though.

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CROCtober

Welcome to CROCtober, the annual celebrations of all things crocodilian, the animal group – not the shoes, during October. The term Crocodilians includes crocodiles, alligators, caimans, and gharials. These creatures are often misunderstood as furious, killing machines but there’s more to them than that. Crocodilians are one of the most endangered group of animals on the planet. Out of the 23 species, 7 of the species are listed as critically endangered. Additionally, 4 species are listed as vulnerable to extinction. That’s not great.

Over the month of CROCtober, I plan to highlight the different species of crocodilians, the troubles they face, some researchers who study them, and how you can help save the crocs. Don’t worry, frog content will still be posted. Stay tuned!

Frog of the Week

Cape Platanna (Xenopus gilli)

Cape Platanna
photo by flickr user Chris Verwey
Conservation status is Endangered

Common Name: Cape Platanna, Gill’s Plantanna, and Cape Clawed Toad
Scientific Name: Xenopus gilli
Family: Pipidae – Tongueless Frog family
Locations: South Africa
Size: 2.3 inches (60 mm)

The Cape Platanna is an aquatic frog that inhabits the highly acidic seepages, marshes, ponds, and lakes of coastal South Africa. These waterbodies are dark in color, allowing the frogs to blend in. The Platanna are able to “see” in this water due to their highly developed lateral line system. This system always them to detect small vibrations in the water. The frogs have highly webbed clawed toes on their back legs to help them swim. They only come to the surface when their wetlands dry up during the summer or when they want to migrate ponds during the mating season. The frogs aestivate during the summer when their ponds dry up by digging deep into the mud.

The Cape Platanna breeds during the winter months between July to October. Unlike most frogs, members of the family Pipidae lack vocal sacs. To communicate with female frogs, the male frogs make a series clicks. Once the female selects her mate, the male grasps her around the waist in the amplexus position. Then, the female lays between 300 – 400 eggs while the male fertilizes them. Neither parent is known to provide any parental care. Once the eggs hatch, the tadpoles take 120 days to complete their metamorphosis.

Cape Platanna Conservation

The International Union for the Conservation of Nature (IUCN) Red List categorizes the Cape Platanna as Endangered with Extinction. There is believed to be only 5 locations where the frogs live. Most of the wetlands that the frog calls home as been filled to make room for housing development and farm lands. Additionally, the frog hybridizes with the African Clawed Frog (Xenopus laevis), reducing their numbers. Better protections are needed to help save them.

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Variable Poison Dart Frog (Ranitomeya variabilis)

Variable Poison Dart Frog
photo by John P. Clare

Common Name: Variable Poison Dart Frog, Splash-back Poison Frog, and Zimmermann’s Poison Frog
Scientific Name: Ranitomeya variabilis
Family: Dendrobatidae – Poison Dart Frog family
Locations: Colombia, Ecuador, and Peru
Size: .6 – .7 inches (17 – 18 mm)

The Variable Poison Dart Frog was originally thought to be only in rain forests in Peru but populations in Colombia and Ecuador were found recently. These frogs live on the forest floor but they also live in trees. They are primarily active during the day aka diurnal. Due to their poisons, not many predators attempt to eat them. The frog’s create their poison with the help of their diet of ants, termites, and beetles. In captivity, they are not poisonous. You can find them in found in the pet trade with many individuals being captive bred. Always make sure to buy frogs or any animal that is captive bred to help fight against the illegal wildlife trade.

Reproduction for the Variable Poison Dart Frog

Mating for the frogs take place after rainfall. Females lay between 2 – 6 eggs in pools of rain water that collect in bromeliad plants. While the female is laying her eggs, the male positions himself facing away from her and fertilizes the eggs. After mating, the female leaves the eggs while the male sits and watches them. Once the eggs hatch in 12 – 14 days, the males carry some of the tadpoles on their back to other plants to help reduce competition between the tadpoles. Not all males care for their offsprings. Eventually in 12 – 14 weeks, the tadpoles complete their metamorphosis.

The International Union for Conservation (IUCN) Red List hasn’t categorized the Variable Poison Dart Frog yet so they sit at Data Deficient. The frog has a wide range that is generally undisturbed. Hopefully, the land stays safe from logging. They are listed in the CITES Appendix II. This requires that the governments were they are found must issue permits for the exportation of the frog.

Frog of the Week

Holy Cross Frog (Notaden bennettii)

Holy Cross Frog
photo by wikiuser Tnarg 12345

Common Name: Holy Cross Frog, Crucifix Frog, and Crucifix Toad
Scientific Name: Notaden bennettii
Family: Myobatrachidae – Australian Ground Frog family
Locations: Australia
Size: 2.7 inches (6.8 cm)

The Holy Cross Frog is a fossorial species of frog found in the  black soil plains and semi-arid grassland regions of western New South Wales and Queensland. During the dry times, the frog burrows down in the ground and surrounds itself in a cocoon to preserve water. They are capable of digging down almost 10 feet (3 meters)! Due to their fossorial lifestyle, the frogs feed primarily on ants and termites. When threatened by predators, the frogs produce a sticky, glue-like substance that predators don’t want to eat. It is advised to wash your hands after handling the Holy Cross Frog and basically any frog.

Once the heavy rains come, the frog will emerge from the ground, ready to breed. The male frogs will move to temporary ponds created by the rains and start to call out to females. The call sounds like a woo. Once the female arrives at the pond, the male glues himself to her back due to his smaller size. Next, the female lays her eggs and the male will fertilize them. Neither parents provide any parental care for their offspring.

Holy Cross Frog
photo by flickr user eyeweed

The International Union for the Conservation of Nature (IUCN) Red List categorizes the Holy Cross Frog as Least Concern for Extinction. The only threats to the species are habitat loss due to farming, climate change, and the introduction of the invasive Cane Toad (Rhinella marina). Researchers have been trying to get the frogs to breed in captivity just in case but have been struggling. Surprisingly, the answer to this problem was a Youtube Clip of a thunderstorm. This clip helps simulate heavy rain storms that gets the frogs in the mood.

New Species

2 New Species of Waterdogs

The Waterdogs are fully aquatic species of salamanders that are paedomorphic. This means that they retain their larval characteristics (gills, etc) throughout their life. They are often mysterious, often living at the bottom of drainages, ponds, and lakes.

Researchers, Craig Guyer, Christopher M. Murray, Henry Bart, Brian I. Crother, Ryan E. Chabarria, Mark A. Bailey, and Khorizon Dunn, have described two new Waterdog species from the southeastern United States. You can read the article here. The two waterdogs were considered to be Gulf Coast Waterdog (Necturus beyeri) but they are physically different than it. Also the researchers suggest changing the name of the Gulf Coast Waterdog to the Western Waterdog.

Escambia Waterdog – photo by Craig Guyer

The first of the new species is the Escambia Waterdog (Necturus mounti). The larvae lacks white spots which differs from the Gulf Coast Waterdog. The adults lack spots on their mandible chin and on the sides of their belly. Their belly is a bright white color as well.

Apalachicola Waterdog – photo by Craig Guyer

The second of the species is the Apalachicola Waterdog (Necturus moleri). They as well lack white spots on their larvae that differs it from the Gulf Coast Waterdog. The adults have spots on their mandible chin and on the sides of their belly. Their belly is dull white in color. Both of the new species can be found around the Florida – Alabama border.

Frog of the Week

Paradoxical Frog (Pseudis paradoxa)

Paradoxical Frog
photo by Hans Hillewaert
least concern

Common Name: Paradoxical Frog, Paradox Frog, Shrinking Frog
Scientific Name: Pseudis paradoxa
Family: Hylidae – Tree Frog Family
Locations:  Argentina, Bolivia, Brazil, Colombia, French Guiana, Guyana, Paraguay, Peru, Suriname, Trinidad and Tobago, and Venezuela
Size: 1.7 – 3 inches (45 – 75 mm)

The Paradoxical Frog is named after a strange phenomenon during their metamorphosis. Their tadpole is the largest tadpole in the world, almost reaching 10 inches (25 cm) long! That is over three times larger than the length of an adult frog! What a paradox! Yet, not all tadpoles exhibit the paradox. Tadpoles that are born in temporary bodies of water with predators transform quickly and leave the water before they get to massive sizes. In permanent bodies of water, they transform slower, thus allowing more growth time.

The Paradoxical Frog is a member of the Tree Frog family – Hylidae but they are never seen in the trees. They live in and around permanent and temporary ponds. These are the same bodies of water that they breed in. The males will call for the ponds for the females. Once the female arrives, the male will grasp her from behind in the amplexus position. Then, the female will start laying her eggs and the male will fertilize them. The eggs are laid in the vegetation near the shore. Neither parent provides any parental care.

The International Union for the Conservation of Nature (IUCN) Red List categorizes the Paradoxical Frog as Least Concern for Extinction. They have a wide spread range and are common throughout it. Some populations are facing declines due to habit loss due to urban development and agriculture.

Frog of the Week

Magdalena Giant Glass Frog (Ikakogi tayrona)

Common Name: Magdalena Giant Glass Frog
Scientific Name: Ikakogi tayrona
Family: Centrolenidae – Glass Frog family
Locations: Colombia
Size: 1.2 inches (28 mm)

The Magdalena Giant Glass Frog is found in the Sierra Nevada de Santa Marta mountain range in the Magdalena department of Colombia, at altitudes up to a mile (1790 meters) high. They are an arboreal species of frog, living up in the trees. During the day, the frogs will hide on the back of leaves, camouflaging in with their translucent skin. Glass Frogs are really small, so even a frog reaching not even 1.5 inches long is considered gigantic.

The males of the species will mark out territory in leaves over hanging a stream. They will fight other males that enter their territory. The males even have humeral spines on their arms that they use to fight the other males. Eventually, the males will start calling for the females. Once the females arrive, the male will grasp her from behind in the amplexus position. Then, the female will lay her eggs on the leaves and the male will fertilize them.

The Magdalena Giant Glass Frog is the only known Glass Frog known that females will provide parental care for their offspring. In the other species, parental care is either provided by the male or not at all. The females will brood the eggs, protecting the eggs from predators and keeping them hydrated. Eventually, the eggs will hatch and the tadpoles will fall into the stream.

The International Union for the Conservation of Nature (IUCN) Red List categorizes the Magdalena Giant Glass Frog as Vulnerable to Extinction. They are found only in a small area where habitat destruction is an increasing problem.

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Crab-eating Frog (Fejervarya cancrivora)

photo by W.A. Djatmiko

Common Name: Crab-eating Frog, Mangrove Frog, Asian Brackish Frog, and Crab-eating Grassfrog
Scientific Name: Fejervarya cancrivora
Family: Dicroglossidae – Forked Tongued Frog family
Locations:  Brunei, Cambodia, China, India, Indonesia, Laos, Malaysia, Myanmar, Singapore, Thailand, and Vietnam.
Introduced Locations: Guam and Papua New Guinea
Size: 3.1 inches (80 mm) for females, 2.75 inches (70 mm) for males

The Crab-eating Frog is thought to be the most salt tolerant amphibians in the entire world. They are able to survive in brackish waters for extended periods of time and briefly survive swimming in salt water. With this species talent, they are able to feast upon crabs and other small crustaceans, hence their name. They are found along the shorelines, mangrove forests, and inland wetlands.

Reproduction for the frogs is pretty standard. They can breed year round but most activity is at the start of the wet season. At the start, the males will call for the females from a water body. Once the female arrives, the male will grasp her from behind in the amplexus positiion. Then, female will lay her eggs and the male will then fertilize them. Neither parent will provide any parental care for the offspring. The eggs will hatch into tadpoles that transform later into frogs.

The Crab-Eating Frog is listed by the International Union for the Conservation of Nature (IUCN) Red List as Least Concern of becoming Extinct. The frog has a wide range and is plentiful throughout it. They especially thrive in rice paddy fields. Potential threats to the survive of the frogs is the habitat destruction and over harvesting the frogs for food.