Tag Archives: snakes

Evolution and venomous snakes: Diet distinguishes look-alikes on two continents

ANN ARBOR — On opposite sides of the globe over millions of years, the snakes of North America and Australia independently evolved similar body types that helped them move and capture prey more efficiently.

Snakes on both continents include stout-bodied, highly camouflaged ambush predators, such as rattlesnakes in North America and death adders in Australia. There are slender, fast-moving foragers on both continents, as well as small burrowing snakes. (more…)

Read More

Study finds turtles are closer kin to birds, crocodiles than to lizards, snakes

What are turtles, and where did they come from?

Precise answers to these questions have long eluded scientists. But new research led by Daniel Field of Yale University and the Smithsonian Institution recasts the turtle’s disputed evolutionary history, providing fresh evidence that the familiar reptiles are more closely related to birds and crocodiles than to lizards and snakes. (more…)

Read More

Oldest existing lizard-like fossil hints at scaly origins

The fossilised remains of a reptile closely related to lizards are the oldest yet to be discovered.

Two new fossil jaws discovered in Vellberg, Germany provide the first direct evidence that the ancestors of lizards, snakes and tuatara (known collectively as lepidosaurs), were alive during the Middle Triassic period – around 240 million years ago.

The new fossil finds predate all other lepidosaur records by 12 million years. The findings are published in BMC Evolutionary Biology. (more…)

Read More

Predators Drive the Evolution of Poison Dart Frogs’ Skin Patterns

Natural selection has played a role in the development of the many skins patterns of the tiny Ranitomeya imitator poison dart frog, according to a study that will be published in an upcoming edition of American Naturalist by University of Montreal biologist Mathieu Chouteau. The researcher’s methodology was rather unusual: on three occasions over three days, at two different sites, Chouteau investigated the number of attacks that had been made on fake frogs, by counting how many times that had been pecked. Those that were attacked the least looked like local frogs, while those that came from another area had obviously been targeted. (more…)

Read More

Fossil Reveals Oldest Evidence of Live Birth in Reptiles

*A fossil from north-eastern China has revealed that terrestrial reptiles were giving birth to live young at least as early as 120 million years ago.*

The newly discovered fossil of a pregnant lizard proves that some squamate reptiles (lizards and snakes) were giving birth to live young, rather than laying eggs, in the Early Cretaceous period – much earlier than previously thought. The fossil shows a pregnant female filled with the tiny skeletons of more than 15 baby lizards at a stage of development similar to that of late embryos of modern lizards. The mother lizard, which is 30 centimetres long (excluding her tail), probably died only a few days before giving birth.

The discovery is described in the journal Naturwissenschaften by scientists from UCL (University College London) and the Institute of Vertebrate Paleontology and Paleoanthropology at the Chinese Academy of Sciences, Beijing. (more…)

Read More

People Aren’t Born Afraid of Spiders and Snakes: Fear Is Quickly Learned During Infancy

There’s a reason why Hollywood makes movies like Arachnophobia and Snakes on a Plane: Most people are afraid of spiders and snakes. A new paper published in Current Directions in Psychological Science, a journal of the Association for Psychological Science, reviews research with infants and toddlers and finds that we aren’t born afraid of spiders and snakes, but we can learn these fears very quickly. 

One theory about why we fear spiders and snakes is because so many are poisonous; natural selection may have favored people who stayed away from these dangerous critters. Indeed, several studies have found that it’s easier for both humans and monkeys to learn to fear evolutionarily threatening things than non-threatening things. (more…)

Read More

Ice-Age Reptile Extinctions Provide a Glimpse of Likely Responses to Human-Caused Climate Change

ANN ARBOR, Mich. — A wave of reptile extinctions on the Greek islands over the past 15,000 years may offer a preview of the way plants and animals will respond as the world rapidly warms due to human-caused climate change, according to a University of Michigan ecologist and his colleagues.

The Greek island extinctions also highlight the critical importance of preserving habitat corridors that will enable plants and animals to migrate in response to climate change, thereby maximizing their chances of survival.  (more…)

Read More