South American Cackling Tree Frogs Mistaken for “Singing” Snakes

In forested regions of Central and South America, there lurks a deadly predator: venomous bushmaster pit vipers (genus Lachesis), reaching over 3m in length (almost twice as long as the average S. American man is tall). One species of this snake, L. muta, has long been thought to “sing” by local natives. But now scientists have found evidence that seems to dispel this myth.

Capable of multi-bite attacks and injection of large amounts of venom that can kill a man, the bushmaster’s singing – which sounds like the loud chuckle of a bird – strikes fear into the heart of any native who hears it. It is fitting, then, that their genus name Lachesis refers to one of the Three Fates in Greek mythology who determined the length of the thread of life. In Greek, Lachesis is the second Fate pertaining “to obtain by lot, by fate, or by the will of the gods.”

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The Three Fates (Moirai) of Greek Mythology. Image of the Flemish Tapestry, Victoria & Albert Museum, London, by PrioryMan.

The legend of these singing snakes has long been a puzzle to scientists, as snakes are not known to be able to emit such calls. In a recent collaborative effort, scientists have gone a long way to solving this puzzle. Researchers from the Catholic University of Ecuador, the Peruvian Institute of Research of the Amazon, Ecuadorian Museum of Natural Sciences, and Colorado State University, USA, have now discovered that the snakes are actually not at all responsible for the singing.

The study, published in Zookeys last week, analysed DNA sequences, external morphology and advertisement calls of two species of treefrogs, the Canelos treefrog (Ecnomiohyla tuberculosa) and the veined treefrog (Trachycephalus typhonius) in Ecuador and Peru. Setting out to determine their phylogenetic relationships in the region, they found a completely new species of tree frog and have called into question previous taxonomic relationships among these frogs.

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Rabb’s fringe-limbed treefrog (Ecnomiohyla rabborum) is one type of marvelous or fringe-limbed treefrog found in Central and South America. They can glide using their webbed hands and feet. Image by Brian Gatwicke.

In describing the advertisement calls of T. typhonius, the authors commented:

“Interestingly, the call of this species is feared by natives in the lower Pastaza basin (Shiwiar, Sapara, Shuar, Achuar people), because it is commonly confused with the “calling” of the bushmaster Lachesis muta (Squamata: Viperidae). This belief is almost certainly incorrect as L. muta cannot vocalize.” (pp. 124).

The researchers measured 14 acoustic parameters of the frogs’ calls, including call duration, note length, and frequency, and describe them as a “cackle of short notes.” They found that the frogs make these calls from tree-holes containing water, where they appear to breed.

It is quite funny imagining natives running for their lives when they hear this call, not knowing that it is actually a harmless tree frog calling for a mate.

Other Fun Facts about Bushmaster Pit Vipers:

  • The bushmaster’s tail ends in a horny spine, which it sometimes vibrates when disturbed. This behaviour has led it to be nicknamed ‘the mute rattlesnake.’
  • They are the longest venomous snake in the New World, growing up to 3 metres long. Large adults can weigh up to 5 kg.  
  • There are three species of bushmaster snakes: L. melanocephala (black-headed bushmaster), L. muta (South American bushmaster) and L. stenophrys (Central American bushmaster).

40 Words For Emotions You’ve Felt, But Couldn’t Explain | Thought Catalog

Have you ever felt an emotion but had no word to describe it? Then consult this post by Brianna West on thoughtcatalog.com. It helpfully lists 40 words that will perfectly cure that lost-for-words, tip-of-the-tongue feeling.

So next time you have a hanker sore, you can relieve it with a bit of ambedo. I dare you to start using them in your everyday conversations and writings. It’s time for some liberosis, people. 

Underwater shipwrecks hold secrets to life as well as pots of gold

The tragic event of losing a ship at sea is one that has occurred far too often in history. The sad remnants of sea-ravaged ships lying forgotten underwater for hundreds of years not only tell us secrets about the disastrous events themselves but also hold valuable physical clues to past times we know little about, including actual treasure troves of gold and jewels. Not surprisingly then, shipwrecks have long intrigued painters, writers, scientists, filmmakers, historians and even professional treasure hunters alike.

We only need to think of the (arguably) hit film The Titanic, in which Kate Winslet and Leonardo DiCaprio are immortalised as tragic lovers on a ship bound for the bottom of the Atlantic. The poem The Wreck of the Hesperus by Henry W. Longfellow even inspired a song by The Beatles’ George Harrison, and is a term my mum uses to describe me when I’m looking particularly unkempt. So it seems that shipwrecks have had such an impact on us that they have even infiltrated the English language.

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The Wreck by Knud-Andreasson Baade c.1835. Wikipedia Commons.

Shipwrecks also have remarkable stories to tell us about the past. With rapid advances in technology, we now have sophisticated remote-sensing and remotely operated diving equipment, allowing diving archeologists to find and reach much deeper underwater sites, meaning that no site is beyond the reach of our research into the past. We only have to think of the 2003 discovery of the shipwreck of The Santa Maria off the coast of Haiti – one of the ships now thought to have carried Christopher Columbus over the Atlantic to America – and the excavation of the 2,000 year-old Antikythera shipwreck to uncover ancient treasures including the world’s first known computer.

Now, scientists have uncovered other secrets related to the rich and deep ecosystems that shipwrecks support in the Gulf of Mexico. Here, over 2,000 shipwrecks languish on the bottom of the sea spanning over 500 years of maritime history from the time of the 16th century Spanish explorers to the American Civil War and through the World War II era. A team of scientists have dived down to discover exactly what kind of life these ships support and how it has been affected by a huge and devastating oil spill in this area (the Deepwater Horizon oil spill in 2010).

In the first ever study of its kind plunging into deep-sea shipwreck ecosystems, the team discovered that the presence of shipwrecks on the seafloor alters what kind of microorganisms are found there. They also revealed that the chemicals used to clean up the oil spill has changed this microbial community, even after four years, thus having knock-on effects on other animals that depend on them like crabs, fish and coral.

The team also found that the oil spill could degrade not only the surrounding ecosystems but also the ships themselves, as the oil seems to increase metal corrosion on the ships’  surfaces. The researchers plan to use innovative 3D-laser and sonar technology to produce high-resolution images of the vessels to document how the oil spill affects their future state of preservation.

What I found most exciting about this study is that it shows how investigating deep-sea shipwrecks can help us monitor the rich ecosystems they support, as well as helping to preserve the precious historic value of the ships themselves. It could also help scientists studying other aspects of the deep sea – a huge part of our planet that still remains mostly a mystery to us.

One thing I am sure about is that the enigma that lies beneath the surface of our oceans  – the secrets of its dark history and ecological treasures – will continue to intrigue and inspire us for a long time to come.

A video about the research can be found here and was presented at the 2016 Ocean Sciences Meeting in New Orleans, U.S.A. yesterday.

Co-authors of the study:

Jennifer Salerno: George Mason University, Fairfax, VA, USA;

Brenda Little, Jason Lee, Ricky Ray: Naval Research Laboratory, Stennis Space Center, MS, USA;

Leila Hamdan: George Mason University, Fairfax, VA, USA.

The language of wolves and dogs is probably more complex than you thought

If like me you tend to struggle with speaking a foreign language, then you’ve probably also experienced that ‘lost in translation’ feeling. During my PhD research studying Aegean wall lizards in Greece I learned various Greek phrases to get by, but the language baffled me all the same. Yes, I’ve said it many times before – it’s all Greek to me.

The origins of human language, and how it has diverged into a massive 6,500 different languages around the world, is an intriguing and complex question that remains largely unsolved, attracting a long history of debate and potential explanations, such as its importance in developing tools.

But we can also gain a lot of insight by studying the early evolution of vocal communication in other animals, particularly in those that are socially and behaviourally similar to us.

Animals in the Canidae family – wolves, domestic dogs, jackals and coyotes – are extremely sociable like us, often hunting and living in large packs and ranging over wide distances. Howling vocalisations help them to communicate over these great distances and are thought to play a role in important social interactions like maintaining group cohesion as well as in territorial advertising. Previous experiments using playbacks have shown that wolves better recognise the “voice” of familiar than unfamiliar individuals, (even if elements of their howls are artificially changed) and howling between individuals depends on how well the two get along.

New research published this week in Behavioural Processes has revealed that canids use different types of howls that are specific to their own species, and even subspecies, revealing new insights about the diversity and specialisation of their vocal communication.

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The grey wolf (Canis lupus) and other canids use howling to communicate over long distances. Wikipedia Commons.

The study, led by Dr Arik Kershenbaum at the University of Cambridge, is the largest of its kind so far. Initially, the researchers diligently gathered 6,000 recordings from captive and wild howling canids from all over the globe, ranging from India to Australia, to Europe and the United States. This included downloading recordings of domestic dog howls from YouTube. Maybe this beauty was part of the sample?

The 6,000 recordings were whittled down to 2,000 from a total of 13 species and subspecies of canids for the final study.  These were fed into a machine learning computer algorithm, which eventually classified them into 21 discrete (distinguishable) types.

I particularly like this computer algorithm method because it avoids previously used human-based classification of howls. In particular, this new computer analysis is more likely to identify subtle similarities and differences between the vocalisations that human assessments could miss.

The study found that the vocalisations were usually very distinct among the 13 different species/subspecies, revealing typical vocal dialects or “vocal signatures” for each group.

But, some bore quite striking similarities, the consequences of which could be drastic. Specifically, similar vocalisations between different species could lead to interbreeding and the resulting hybrids could decrease genetic diversity, outcompete indigenous pure species, and even cause sterility. In one case, it could even threaten the survival of one species – the red wolf (Canis rufus).

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The critically endangered red wolf (Canis rufus). Success of reintroductions in the U.S. has been threatened by hybridisation with coyotes. The similar vocalisations of coyotes and red wolves may be one reason why hybridisation frequently occurs. Wikipedia Commons.

Red wolves, which had been hunted almost to extinction in the U.S. by the middle of the 20th century, have been reintroduced into the wild but their success has been threatened by hybridisation with coyotes. This may be in part because the two species were found to use very similar vocalisations: modulated, whining howls. The researchers suggest that these new insights into howling behaviour could help keep the red wolf and coyote populations apart and so prevent the red wolf from disappearing altogether.

I think the next step is to develop ways of measuring how these vocal signals are transmitted to the actual ear of intended, natural receivers – that is, conspecifics – in natural environments, and their ensuing behavioural responses to them. This way we can understand how the howls have evolved to become tuned to effectively transmit to the ear of conspecifics in a given environment, as well as what type of information they are actually communicating.

For now, though, we are getting closer to realising the sheer complexity and specialisation of vocal communication in animals, which can have important consequences on species conservation.

Perhaps this type of research can also tell us something about how our own language skills and diverse dialects have arisen.  We know that primitive humans started talking to each other at some point between 50,000 to 100,000 years ago, after which complex language quickly developed, with languages being universally connected by syntax.

 

 

Octopus colours signal when to fight… and when to flee

If you have ever been unlucky enough to get involved in a fight, before you swung a punch wouldn’t it have been better to know first whether you stood a chance against your opponent? (Especially if you lost the fight and ended up in hospital). That way, if it’s Mike Tyson squaring up to you, you can get out of there, pronto.

In the case of octopuses, they’re not friendly neighbours. They’re usually solitary and don’t much like sharing their space and food, so are pretty intolerant of each other when they meet. But, instead of fighting off every rival they come across – which would be risky if they are unlucky enough to meet the Mike Tyson of the octopus world – they seem to have a way of assessing whether they are an even match.

New research has shown that when gloomy octopuses (Octopus tectricus) come across each other, they change their colour to display whether they want to fight … or not.

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The gloomy octopus (Octopus metrics) lives up to its name – it is usually solitary and very intolerant of other individuals. Wikipedia Commons.

The study, published in Current Biology yesterday, showed that the outcomes of meetings between two octopuses are reliably predicted by the colours displayed by the opponents.

Led by Dr David Scheel at Alaska Pacific University, the team of researchers observed that, if two octopuses both stayed dark, they were more likely to engage in “grappling” – the octopus equivalent of a fist fight.

On the other hand (tentacle), if one octopus becomes paler while the other remains dark, the paler one tends to flee.

In this way, the octopuses display colours that help them avoid having to fight an obviously more beefy individual, which could end up injuring them (or worse). Matching their colours instead helps them face a more evenly matched opponent.

Much like how you would avoid Mike Tyson in a fight (obvs) but maybe, just maybe, treat your younger and cocky sibling to a sucker punch.

This is one of the first studies to show us how colours in octopuses predict the outcome of their aggressive interactions. Nice one.

 

 

 

 

 

 

 

 

 

 

Murmurations in birds

Check out this fascinating post about murmuration – a type of flocking behaviour – in starlings during winter. The gracefully sweeping clouds of birds are wonderful to watch against the evening sky (if you haven’t see it before, check it out here). The reason why starlings perform this behaviour still confounds scientists. In her blog post below, @GrrlScientist describes murmuration and reveals some of the research exploring why it happens…

Throughout the northern hemisphere, the dark cold months between November and February are the time when European starlings, Sturnus…

Source: What The Flock? Birds Perform Intricate Aerial Ballets In Winter — But We’re Not Sure Why — Medium