Shake, rattle and strike. It is possibly one of the most terrifying sounds in the animal kingdom, but how the rattlesnake evolved its chilling warning signal is a mystery. Now a study suggests the rattle evolved long after the tail-shaking behaviour.
The evolution of the rattle has baffled scientists because, unlike other complex physical traits like eyes or feathers, it has no obvious precursor or intermediate stage.
“There is no half-rattle,” says David Pfennig at the University of North Carolina at Chapel Hill.
One theory is that ancestral snakes shook their tails to warn off predators, and the noise-making rattle – which is made of a series of hollow, modified keratin scales – evolved later as a more effective signal that took advantage of the pre-existing behaviour. This may be why many rattle-less snakes also shake their tails.
To test the idea, Pfennig and his colleague prodded 56 species of venomous and non-venomous snakes with a fake rat on a stick and recorded their defensive tail shakes.
They found that the more closely related a snake was to the rattlesnake, the more similar its tail shake was in speed and duration.
“This suggests the defensive tail vibration came first, perhaps as a physiological response to stress, and that became a reliable cue to predators that the snake was about to strike,” says Pfennig. “When the rattle evolved, it became an even more effective signal.”
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The critically endangered Hawaiian crow can use sticks to deftly fish for food that is out of reach, according to a new study. The discovery means there are now two known tool-using species of crows.
“The Hawaiian crows are incredibly good at using tools,” said lead study author Christian Rutz, a biologist at the University of St Andrews in the United Kingdom. “What we see is similar to the really skilled tool handling in New Caledonian crows.”
Until now, New Caledonian crows had been the only corvid (a group that includes crows, ravens and rooks) species known to use tools. These birds have become famous for their expert ability to fashion hooks from sticks to snag larvae and insects from crevices in logs or branches. [Creative Creatures: 10 Animals That Use Tools]
Rutz had studied the New Caledonian crow for more than a decade. In one paper, published in the journal Nature in 2012, he and his colleagues showed how the birds have physical characteristics that enable their tool control: straight bills and very large eyes with a large field of binocular vision.
Rutz told Live Science he wanted to look for other birds that shared these features, thinking those traits could be preadaptations for tool use. That led him to the Hawaiian crow, also called the ‘alalā (pronounced AH-la-la).
The one problem was that the birds had been declared extinct in the wild by 2004. (Just 131 are alive today.) So Rutz got in touch with San Diego Zoo Global, a nonprofit organization that operates the San Diego Zoo and was breeding the ‘alalā in captivity in Hawaii. People at the captive breeding facility told him they had sometimes seen the birds use sticks but didn’t think much of it.
“I immediately booked my flight to Hawaii,” Rutz said.
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Native forest birds on the Hawaiian island of Kauai are rapidly dying off and facing the threat of extinction as climate change heats up their habitat and allows mosquito-borne diseases to thrive, according to a study released Wednesday. science news Continue reading Climate change blamed for collapse of Hawaiian forest birds
As bear-human conflicts rise, Colorado is running out of places to relocate bears, a system that has questionable value. science news Continue reading As bear-human conflicts rise, Colorado runs out of places to relocate bears
After five years of drought, the native Chinook salmon that the men were reeling in this past week were there only because state and federal agencies have stepped in to do much of the salmon-raising that California’s overtapped rivers once did. science news Continue reading California’s native salmon struggling in 5th year of drought
Any dog owner can tell you, dogs are excellent listeners. But how much do they really understand?
According to a new study that will be published in Science this week, they understand more that you’d think.
Using functional magnetic resonance imaging technology (fMRI) researchers were able to observe the brain activity in dogs as they listened to their trainer’s voices.
The study involved 13 dogs (six border collies, four golden retrievers, one German shepherd, and one Chinese crested) volunteered by their human families to participate in the research. The dogs were specially trained to lie very still inside the fMRI scanner, and were free to get up during the study if they wanted to. But they were all very good dogs, and managed to stay still enough during the testing for researchers to get data on all 13.
The dogs heard their trainers say positive phrases in a positive tone, positive phrases in a neutral tone, neutral phrases in a positive tone and neutral phrases in a neutral tone.
All phrases were Hungarian expressions (the researchers were from Eötvös Loránd University in Budapest) used by all of the dogs’ owners to praise the pups.
The praise phrases were: azaz, meaning “that’s it”; ügyes, which means “clever”; and jól van, which translates to “well done.” The neutral phrases were: akár, which means “as if”; olyan, meaning “such”; and mégsem, which means “yet.” Each of the neutral words was selected for it’s phonetic similarity to the praise words, and for having no real meaning to the dogs. (Using the words for “bath” or “let’s go to the vet,” which dogs might associate with activities, might have thrown off the study.)
When the dogs listened to a recording of their trainer saying the words in each of the combinations of phrases and tone the researchers found that while the dogs recognized praise words, their reward centers of the brain only activated when they heard praise words in a praising tone.
“During speech processing, there is a well-known distribution of labor in the human brain. It is mainly the left hemisphere’s job to process word meaning, and the right hemisphere’s job to process intonation. The human brain not only separately analyzes what we say and how we say it, but also integrates the two types of information, to arrive at a unified meaning. Our findings suggest that dogs can also do all that, and they use very similar brain mechanisms,” lead researcher Attila Andics said.
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Ecosystem Ambassadors: The Orangutans of Borneo
To see more of Mattias’ incredible wildlife photography from Borneo and beyond, follow @mattiasklumofficial on Instagram.
Perched as high as 210 feet (64 meters) up in the rainforest canopy, photographer and filmmaker Mattias Klum (@mattiasklumofficial) patiently waits to meet “the man of the forest” — the Malay meaning of orangutan. For the last three decades, he has documented one of the world’s oldest rainforests in Borneo. “One of the ambassadors, one of the great storytellers, in their own right, is really the orangutan, because they are so well adapted to these ecosystems,” Mattias says. “But when these emerald realms go up in smoke or they’re changed into huge monocrops, they cannot cope with it very easily, and they lose their abilities to survive.” Along with the fauna and flora he photographs, Mattias honors orangutans as “fascinating, beautiful, engaging reminders of the vulnerability and our interconnectivity with nature. We are in fact very much dependent on these ecosystems and their species to function for our own benefit — I think that’s the most beautiful thing.”
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Scientists today announced the discovery of a new species of pterosaur from the Patagonia region of South America. The cranial remains were in an excellent state of preservation and belonged to a new species of pterosaur from the Early Jurassic. The researchers have named this new species ’Allkauren koi’ from the native Tehuelche word ‘all’ for ‘brain’, and ‘karuen’ for ‘ancient’.
Pterosaurs are an extinct group of flying reptiles that lived during most of the Mesozoic Era. This group had an extraordinary adaptation to flight, including pneumatic bones to lighten its weight, and an elongated digit supporting a wing membrane. However, pterosaur neuroanatomy is known from only a few three dimensionally preserved remains and, until now, there was no information on the intermediate forms. This study therefore provides new information on the origin, tempo and mode of evolution in this particular group of flying reptiles.
The fossil of Allkaruen koi was found in northern central Chubut Province, Patagonia Argentina and the remains included a superbly preserved and uncrushed braincase. In order to study the neurocranial anatomy, researchers used computed tomography to observe, in three dimensions, the cranial endocast and the inner ear. Subsequently, a comprehensive phylogenetic analysis of the group was performed, including these cranial data and other anatomical features. “Allkaruen, from the middle lower jurassic limit, shows an intermediate state in the brain evolution of pterosaurs and their adaptations to the aerial environment”, said Dr Diego Pol, who is part of the research team. “As a result, this research makes an important contribution to the understanding of the evolution of all of pterosaurs.”
Citation to the article: Codorniú L, Paulina Carabajal A, Pol D, Unwin D, Rauhut OWM. (2016) A Jurassic pterosaur from Patagonia and the origin of the pterodactyloid neurocranium. PeerJ4:e2311 https://doi.org/10.7717/peerj.2311
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A new group of critically endangered primates has been spotted in Vietnam, raising hopes the rare creatures may not be wiped out in the next decade as scientists had feared.
The Delacour’s langur, black and white with a full face of whiskers, is indigenous to Vietnam, but their numbers have dwindled in recent years because of poaching and mining activity in the country’s northern forests.
A team of scientists from Fauna and Flora International spotted a group of about 40 of the primates, mostly juveniles and infants, bringing their total population to less than 250.
“It’s great news for this particular species because had we not found this new population, they were in grave danger of being wiped out within a decade,” spokeswoman for FFI in Vietnam, Akofa Wallace, told AFP Tuesday.
“The fact that they are breeding is brilliant news,” she added.
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