Dolabrifera nicaraguana

<p>Sentinel warning calls in <a href="https://www.earth.com/news/do-birds-dream-of-flying-scientists-say-they-now-know-the-answer/">birds</a> may be universally understood, transcending continental boundaries, according to a new study.&nbsp;</p>



<p>This discovery not only expands our understanding of animal communication but also hints at an evolutionary convergence in vocal signals related to danger.</p>



<h2 class="wp-block-heading" id="h-signs-of-danger">Signs of danger</h2>



<p>The research was led by Henry Pollock, executive director of the Southern Plains Land Trust, and Jonah Dominguez, a graduate student at the <a href="https://illinois.edu/" target="_blank" rel="noreferrer noopener">University of Illinois Urbana-Champaign</a>.</p>



<p>Sentinel species, like the Paridae family, are pivotal in mixed-species groups for their distinct alarm calls. These calls, like the “chick-a-dee-dee-dee” of chickadees, are recognized by various bird species, emphasizing their role as universal signals of danger.&nbsp;</p>



<h2 class="wp-block-heading" id="h-anti-predator-behavior-nbsp">Anti-predator behavior&nbsp;</h2>



<p>“Many animals form mixed-species groups, and the thought is that this is an anti-predator behavior,” said Pollock. “There is safety in numbers, and there is a benefit to surrounding yourself with a more diverse set of eyes and ears."</p>



<p>"However, you have to be able to understand the information that the others around you give to make use of it.”</p>



<h2 class="wp-block-heading" id="h-focus-of-the-study-nbsp">Focus of the study&nbsp;</h2>



<p>The research team set out to investigate whether bird communities across three continents – North America, Europe, and Asia – could interpret the alarm calls of a previously unknown sentinel, the dusky-throated antshrike, a Central and South American bird known for its sentinel role.</p>



<p>The study included contributions from Mark Hauber (GNDP) and international collaborators from Serbia and China.&nbsp;</p>



<h2 class="wp-block-heading" id="h-surprising-results">Surprising results</h2>



<p>The experts played warning calls of the dusky-throated antshrike to different bird flocks. They theorized that birds would react most strongly to familiar local sentinel calls. But the results were surprising.</p>



<p>“We expected to see some kind of response to the novel antshrike’s calls, but predicted that birds wouldn’t respond as strongly to it as their own local sentinel’s calls,” said Dominguez.&nbsp;</p>



<p>“However, we were surprised to find no statistical difference in how birds responded to the local versus foreign sentinel’s alarm call. Birds were responding to the unfamiliar antshrike’s call as if it was a bird they’ve known their whole lives.”&nbsp;&nbsp;</p>



<h2 class="wp-block-heading" id="h-universal-recognition-nbsp">Universal recognition&nbsp;</h2>



<p>According to the researchers, flocks of birds across all three continents responded equally as strongly to the unfamiliar antshrike’s warning calls as they did to familiar, local sentinel’s warning calls.&nbsp;</p>



<p>The experts say this finding suggests there is something to sentinel calls that makes them universally recognizable.&nbsp;</p>



<p>For messages that contain important information, such as a warning call for danger, evolution likely converges on similar sounding calls that help get across the message as quickly as possible, according to the researchers.</p>



<h2 class="wp-block-heading" id="h-central-theme-nbsp">Central theme&nbsp;</h2>



<p>“It’s possible that these calls are more readily recognized across species because they have a central theme – essentially something about them that is unique and conserved despite millions of years in evolutionary history,” explained Dominguez.&nbsp;</p>



<p>“There is research in other animals on specific amplitudes and frequencies of sound that cause innate responses, even in animals that are unfamiliar with those sounds. Our study can help researchers figure out what those acoustic elements might be for birds.”</p>



<h2 class="wp-block-heading" id="h-signal-recognition-nbsp">Signal recognition&nbsp;</h2>



<p>“What’s amazing is that our findings are consistent across three different continents with completely different bird communities, which suggests there is some signal encoded within these sentinel alarm calls that cause birds to respond to them, independent of previous experience with that signaler,” explained Pollock.&nbsp;</p>



<p>“This really highlights that signal recognition is not always something that has to be learned through environmental experience.”</p>



<h2 class="wp-block-heading" id="h-future-research-prospects-nbsp">Future research prospects&nbsp;</h2>



<p>The researchers said the study opens the door to many future research directions. They noted that testing birds with the calls of other sentinels and getting more granular in terms of the behavioral responses are potential next steps.</p>



<h2 class="wp-block-heading" id="h-defining-sentinel-species">Defining sentinel species</h2>



<p>Dominguez wants to find the common thread among sentinel birds in an effort to standardize what is categorized as a sentinel species across the literature.&nbsp;&nbsp;</p>



<p>“Sentinel species are not very well defined, as the term is used nebulously for any animals that engage in mixed-species foraging and signaling,” said Dominguez.&nbsp;</p>



<p>“There’s lots of birds that we don’t typically think of as sentinels being classified as them in the literature, and others that probably are sentinels that are being overlooked. I want to figure out if there’s a common thread between them, and whether the term should be used on the species level or more on a flock level.”</p>



<p>The study is published in the journal <a href="http://dx.doi.org/10.1098/rsbl.2023.0332" target="_blank" rel="noreferrer noopener"><em>Biology Letters</em></a>.</p>



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Sentinel warning calls seem to be universally understood by birds

Sentinel warning calls in birds may be universally understood, transcending...

<p>A recent study by a team of researchers from Italy, Norway, Canada, and the US suggests that before their eventual <a href="https://www.earth.com/news/nuclear-winter-dinosaurs-were-likely-killed-by-dust/">extinction</a>, dinosaurs might have faced repeated "volcanic winters" that left them in a weakened state.&nbsp;</p>



<p>These findings come from an analysis of sulfur and fluorine gasses trapped in ancient volcanic rocks from the <a href="https://www.amnh.org/exhibitions/dinosaurs-ancient-fossils/extinction/deccan-traps-volcanoes#:~:text=The%20Deccan%20Traps%20date%20back,volcanic%20eruption%20ever%20on%20land." target="_blank" rel="noreferrer noopener">Deccan Traps supervolcano</a>, which erupted around 200,000 years before the asteroid impact that is widely believed to have caused the dinosaurs’ extinction.</p>



<h2 class="wp-block-heading" id="h-studying-volcanic-winters">Studying volcanic winters</h2>



<p>The study, which focuses on these gases, reveals that their release could have caused global temperatures to drop by up to 18 degrees Fahrenheit (10 degrees Celsius).&nbsp;</p>



<p>This discovery contributes to the ongoing debate among paleontologists and scientists regarding the precise cause of the dinosaurs’ demise. The research aligns with the "press-pulse extinction model," which suggests that a combination of factors led to the extinction event.</p>



<h2 class="wp-block-heading" id="h-unstable-climate-conditions">Unstable climate conditions</h2>



<p>“Our research demonstrates that climatic conditions were almost certainly unstable, with repeated volcanic winters that could have lasted decades, prior to the extinction of the dinosaurs,” said study co-author Don Baker, a geologist at <a href="https://www.mcgill.ca/" target="_blank" rel="noreferrer noopener">McGill University</a> in Montreal.&nbsp;</p>



<p>“Our work helps explain this significant extinction event that led to the rise of mammals and the evolution of our species.”</p>



<h2 class="wp-block-heading" id="h-how-the-research-was-conducted-nbsp">How the research was conducted&nbsp;</h2>



<p>The team analyzed sulfur and fluorine compounds in samples from the Deccan Traps in India’s Western Ghats, near Bombay. They employed synchrotron radiation x‐ray fluorescence spectrometry to measure these compounds’ concentrations. Baker likened the process to cooking pasta, where a small amount of the salt in boiling water is absorbed by the pasta.&nbsp;</p>



<p>Similarly, the team estimated the volume of sulfur and fluorine gases that entered the atmosphere during the Cretaceous period based on the compounds’ presence in the lava rocks.</p>



<h2 class="wp-block-heading" id="h-critical-insights-nbsp">Critical insights&nbsp;</h2>



<p>Notably, the researchers found that the highest sulfur content, as high as 1,800 parts-per-million, correlated with a drop in temperature during the late Cretaceous period. They estimated that between 86,000 and 466,000 cubic-kilometers of sulfur gas were released into the atmosphere, leading to significant climatic changes.</p>



<p>Although the team did not attribute major climate change to fluorine gases, they noted these gases' toxic local effects, including acid rain, crop failure, and livestock poisoning, as observed in historical accounts of the Laki volcano eruptions in Iceland in the 18th century. These effects might have similarly impacted the dinosaurs’ environment.</p>



<h2 class="wp-block-heading" id="h-multiple-triggers">Multiple triggers</h2>



<p>The researchers conclude that the Deccan Traps’ volcanic activity set the stage for a global biotic crisis by triggering repeated short volcanic winters.&nbsp;</p>



<p>However, they believe the "final blow" was the Chicxulub asteroid impact in Mexico, which caused massive environmental devastation. This impact, combined with the preceding volcanic activity, likely accelerated the dinosaurs’ extinction.</p>



<h2 class="wp-block-heading" id="h-study-implications">Study implications</h2>



<p>The study, published in the journal <a href="https://www.science.org/doi/10.1126/sciadv.adg8284" target="_blank" rel="noreferrer noopener"><em>Science Advances</em></a>, highlights the intricate interplay of environmental factors leading up to one of Earth’s most significant extinction events.&nbsp;</p>



<p>“Our dataset indicates that volcanic-driven climate disturbance was already underway,” the researchers noted, underscoring the complexity of the events that led to the end of the dinosaur era.</p>



<h2 class="wp-block-heading" id="h-more-about-volcanic-winters">More about volcanic winters</h2>



<p>As mentioned above, volcanic winters are climatic events resulting from major volcanic eruptions that inject large amounts of ash and sulfur dioxide (SO2) into the Earth's stratosphere. Let's dig a little deeper.</p>



<h3 class="wp-block-heading" id="h-mechanism-of-volcanic-winters">Mechanism of volcanic winters</h3>



<p>Eruption Dynamics: Large volcanic eruptions expel ash and gases high into the stratosphere.</p>



<p>Formation of Sulfur Aerosols: The sulfur dioxide reacts to form sulfuric acid aerosols, which reflect sunlight away from Earth, leading to cooling.</p>



<p>Longevity in the Stratosphere: These aerosols can remain in the stratosphere for years, prolonging their cooling effect.</p>



<h3 class="wp-block-heading" id="h-volcanic-winters-impact-on-climate">Volcanic winters' impact on climate</h3>



<p>Global Cooling: Volcanic winters typically result in a noticeable drop in global or regional temperatures.</p>



<p>Weather Pattern Disruptions: These temperature changes can alter normal weather patterns, causing droughts or excessive rainfall.</p>



<p>Agricultural Impact: Reduced sunlight and cooler temperatures adversely affect crop yields, potentially leading to famines.</p>



<h3 class="wp-block-heading" id="h-historical-instances">Historical instances</h3>



<p>The Year Without a Summer (1816): Following the 1815 eruption of Mount Tambora, 1816 experienced dramatically lowered temperatures, leading to widespread crop failures.</p>



<p>The Toba Catastrophe (Around 74,000 Years Ago): The Toba super-volcano eruption is believed to have caused a decade-long volcanic winter, severely impacting early human populations.</p>



<h3 class="wp-block-heading" id="h-modern-concerns-and-future-risks">Modern concerns and future risks</h3>



<p>Today, advanced monitoring and climate modeling allow for better prediction and preparedness for volcanic winters. A major eruption today could significantly impact our globalized society, emphasizing the need for continued vigilance and preparedness.</p>



<p>In summary, volcanic winters, though rare, pose a significant risk due to their ability to alter global climates and disrupt human activities. Understanding and preparing for these events is crucial in our increasingly interconnected world.</p>



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Volcanic winters weakened the dinosaurs before the asteroid hit

A recent study by a team of researchers from Italy,...

Brittle,Stars,Or,Ophiuroids,Are,Echinoderms,In,The,Class,Ophiuroidea

<p>In the quest to understand intelligence and learning, humans have often focused on brain size as a key factor. However, a fascinating study on brainless brittle stars challenges this notion, revealing that these creatures are capable of learning through experience, despite lacking a centralized brain.</p>



<h2 class="wp-block-heading" id="h-enigmatic-brittle-stars">Enigmatic brittle stars</h2>



<p>Brittle stars, related to <a href="https://www.earth.com/news/crown-of-thorns-starfish-are-natures-ultimate-coral-predators-and-they-are-winning/" target="_blank" rel="noreferrer noopener">starfish</a>, are fascinating marine creatures known for their secretive nature. They spend most of their time hidden under rocks or buried in sand, with their bodies consisting of five wiggly arms connected to a nerve ring near their mouth, instead of a traditional brain.</p>



<p><a href="https://jnotar.github.io/" target="_blank" rel="noreferrer noopener">Julia Notar</a>, the lead author of the study conducted at Duke University under <a href="https://scholars.duke.edu/person/sjohnsen" target="_blank" rel="noreferrer noopener">Professor Sönke Johnsen</a>, emphasizes the uniqueness of the brittle star's nervous system. "There's no processing center," explains Notar. "Each of the nerve cords can act independently, functioning more like a committee than under a central boss."</p>



<h2 class="wp-block-heading" id="h-learning-by-association">Learning by association</h2>



<p>Notar's research posits that brittle stars can learn through classical conditioning, a learning process where an organism learns to associate different stimuli.</p>



<p>One example of classical conditioning is demonstrated by Pavlov's famous experiments with dogs. When repeatedly fed at the ringing of a bell, they eventually start drooling at just the sound of the bell, even without food present.</p>



<p>Similarly, humans experience this often. When you repeatedly hear the “ding” of a smartphone alert, the sound eventually takes on a special meaning. The mere ping or buzz of someone's phone, if it matches your phone's chime, can prompt you to reflexively reach for your phone, expecting the next text, email, or Instagram post.</p>



<p>Researchers have demonstrated classical conditioning in starfish in a few previous studies. However, most <a href="https://www.earth.com/news/sea-stars-may-actually-be-walking-heads-with-no-bodies/" target="_blank" rel="noreferrer noopener">echinoderms</a>, a diverse group encompassing around <a href="https://link.springer.com/article/10.3758/s13420-021-00492-3" target="_blank" rel="noreferrer noopener">7,000 species</a> including brittle stars, brainless starfish, <a href="https://www.earth.com/news/sea-urchins-are-struggling-to-survive-because-they-cant-get-a-grip/" target="_blank" rel="noreferrer noopener">sea urchins</a>, and <a href="https://www.earth.com/news/discovery-eating-sea-cucumbers-can-prevent-diabetes/" target="_blank" rel="noreferrer noopener">sea cucumbers</a>, remain untested in this area.</p>



<h2 class="wp-block-heading" id="h-how-the-study-was-conducted">How the study was conducted</h2>



<p>To determine if brittle stars can learn, researchers placed 16 black brittle stars (<em>Ophiocoma echinata</em>) in individual water tanks and recorded their behavior with a video camera.</p>



<p>They trained half of the brittle stars by dimming the lights for 30 minutes at each feeding time. Whenever the lights went out, the researchers placed a morsel of shrimp -- a favorite of the brittle stars -- just out of reach in the tanks.</p>



<p>The researchers fed the other half the same amount of shrimp but did so under lit conditions, never coinciding with the 30-minute dark periods.</p>



<h2 class="wp-block-heading" id="h-watching-brittle-stars-learn">Watching brittle stars learn</h2>



<p>Regardless of light conditions, the animals mostly hid behind the filters in their tanks, emerging only for meals. However, only the brittle stars that received training learned to associate darkness with food.</p>



<p>In the early stages of the 10-month experiment, all the animals remained hidden when the lights dimmed. Over time, the trained brittle stars formed a connection between darkness and feeding time. They began to anticipate food and emerged from hiding whenever the lights went out, even before shrimp was introduced to the tanks.</p>



<p>These brittle stars had learned to associate the dimming lights with the likelihood of food. They responded without needing to smell or taste the shrimp. The mere dimming of the lights was sufficient to prompt them to emerge for dinner.</p>



<p>Even after a 13-day break without training, which involved repeatedly dimming the lights without feeding, the brittle stars still remembered this association.</p>



<h2 class="wp-block-heading" id="h-implications-and-future-research">Implications and future research</h2>



<p>Notar finds these <a href="https://rdcu.be/drHJO" target="_blank" rel="noreferrer noopener">results</a> exciting, as they demonstrate classical conditioning in a group of animals previously not known for such learning capabilities. </p>



<p>“Knowing that brittle stars can learn means they’re not just robotic scavengers like little Roombas cleaning up the ocean floor,” Notar said. “They're potentially able to expect and avoid predators or anticipate food because they’re learning about their environment.”</p>



<p>The study opens doors to further explore how creatures with non-standard nervous systems learn and remember. Notar plans to delve deeper into the mechanisms behind the brittle stars' learning abilities, aiming to answer the intriguing question: "How do they do it?"</p>



<p>This research fundamentally challenges our understanding of learning and intelligence in the animal kingdom. It suggests that brain size or structure may not be the sole determinants of an organism's ability to learn and adapt to its environment, paving the way for a broader and more inclusive study of intelligence in nature.</p>



<h2 class="wp-block-heading" id="h-more-about-brittle-stars">More about brittle stars</h2>



<p>As discussed above, brittle stars, fascinating and unique echinoderms, exhibit remarkable features and behaviors in marine ecosystems. Belonging to the class Ophiuroidea, these creatures are close relatives of sea stars, but they stand out due to their distinct physical characteristics and ecological roles.</p>



<h3 class="wp-block-heading" id="h-physical-description-and-diversity">Physical description and diversity</h3>



<p>Brittle stars typically possess a central disc and five slender, highly flexible arms. Unlike sea stars, their arms do not contain vital organs and are sharply demarcated from the central disc. This structure enables them to move swiftly through the water and across the seabed. They exhibit a wide array of colors and patterns, enhancing their appeal.</p>



<p>There are over 2,000 known species of brittle stars, varying greatly in size and form. Some species have smooth arms, while others have spiny or adorned ones. Their size can range from a few centimeters to nearly a meter in arm span, with the central disc usually being relatively small.</p>



<h3 class="wp-block-heading" id="h-habitat-and-distribution">Habitat and distribution</h3>



<p>Brittle stars inhabit diverse marine environments, from shallow coral reefs to the deep sea. They often hide under rocks, in coral crevices, or within seagrass beds during the day. Some species even live in symbiotic relationships with other marine organisms, such as corals.</p>



<p>Their global distribution is impressive, with species found in every ocean and at various depths, some reaching as deep as 6,000 meters. This wide distribution highlights their adaptability to different environmental conditions.</p>



<h3 class="wp-block-heading" id="h-feeding-and-nutrition">Feeding and nutrition</h3>



<p>Brittle stars are mostly scavengers and detritivores, feeding on dead organic material and small organisms. They use their flexible arms to capture food particles, which they then transport to their mouths. Some species are also known to be suspension feeders, using their arms to catch plankton and other small particles from the water column.</p>



<h3 class="wp-block-heading" id="h-reproduction-and-lifecycle">Reproduction and lifecycle</h3>



<p>Brittle stars reproduce both sexually and asexually. In sexual reproduction, they release eggs and sperm into the water, where fertilization occurs. The larvae then go through several planktonic stages before settling on the seafloor and metamorphosing into juveniles.</p>



<p>Asexual reproduction occurs through fragmentation, where a part of an arm breaks off and regenerates into a new individual. This ability also aids in their survival, as they can readily regenerate lost limbs.</p>



<h3 class="wp-block-heading" id="h-ecological-role-and-importance">Ecological role and importance</h3>



<p>Brittle stars play a crucial role in marine ecosystems. As scavengers, they aid in the decomposition process and nutrient cycling. They also serve as prey for various marine animals, including fish and crabs.</p>



<p>Their presence in various habitats makes them good indicators of environmental health. Some species are particularly sensitive to changes in water quality, making them useful in monitoring the impact of pollution and climate change on marine ecosystems.</p>



<h3 class="wp-block-heading" id="h-conservation-status">Conservation status</h3>



<p>While many brittle star species are abundant, some face threats from habitat destruction, pollution, and climate change. Their conservation is essential for maintaining the health and diversity of marine ecosystems.</p>



<p>In summary, brittle stars are not just captivating creatures but also vital components of the ocean's biodiversity. Their unique adaptations and ecological roles make them an important subject of study in marine biology and conservation efforts.</p>



<p>The full study was published in the journal <a href="https://link.springer.com/article/10.1007/s00265-023-03402-x">Behavioral </a><a href="https://link.springer.com/article/10.1007/s00265-023-03402-x" target="_blank" rel="noreferrer noopener">Ecology and Sociobiology</a>.</p>



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Brittle stars have no brain but still manage to learn

In the quest to understand intelligence and learning, humans have...

<p>A recently published study reveals fascinating new insights into the history of ancient animals. Researchers Miengah Abrahams and Emese M. Bordy from the <a href="https://uct.ac.za/" target="_blank" rel="noreferrer noopener">University of Cape Town</a>, South Africa, have made a monumental fossil discovery of what seems to be bird tracks. This find indicates that creatures roamed the earth over 210 million years ago on feet resembling those of modern birds.</p>



<h2 class="wp-block-heading" id="h-the-trisauropodiscus-footprints">The <em>Trisauropodiscus</em> footprints</h2>



<p>For years, the enigmatic three-toed footprints known as <em>Trisauropodiscus</em>, prevalent in fossil sites across southern Africa, have puzzled scientists. Debates have centered around the type of animals that might have left these distinct tracks and the exact number of ichnospecies (species identified from trace fossils) of <em>Trisauropodiscus</em>.</p>



<p>In their study, Abrahams and Bordy reevaluated the fossil records of these footprints. They scrutinized physical fossil evidence and reviewed previously published materials. Their focus was on <em>Trisauropodiscus</em> tracks from four sites in Lesotho, dating back to the Late Triassic and Early Jurassic Periods.</p>



<h2 class="wp-block-heading" id="h-detailed-analysis-at-maphutseng">Detailed analysis at Maphutseng</h2>



<p>A significant aspect of their research involved an in-depth field-based examination of footprints at an 80-meter-long tracksite in Maphutseng. Here, they discovered two distinct morphologies among the Trisauropodiscus footprints. The first type bears resemblance to certain non-bird dinosaur tracks, while the second closely matches the size and proportions of bird footprints.</p>



<p>These tracks present a conundrum, as they do not directly correspond to any known fossil animals from this era and region. Intriguingly, the oldest of these footprints, over 210 million years in age, predates the earliest known true bird body fossils by 60 million years.</p>



<h2 class="wp-block-heading" id="h-theories-on-the-bird-track-makers">Theories on the bird track makers</h2>



<p>The researchers propose that these tracks could have been created by early dinosaurs, possibly even <a href="https://www.earth.com/news/how-did-bird-hipped-dinosaurs-evolve/" target="_blank" rel="noreferrer noopener">ancestors of a near-bird lineage</a>. However, they also consider the possibility that other reptiles, related to dinosaurs, might have independently evolved bird-like feet. This discovery pushes back the origin of bird-like feet to at least the Late Triassic Period.</p>



<p>The authors add, “Trisauropodiscus tracks are known from numerous southern African sites dating back to approximately 215 million years ago. The shape of the tracks is consistent with modern and more recent fossil bird tracks, but it is likely a dinosaur with a bird-like foot produced Trisauropodiscus.”</p>



<p>In summary, this mysterious research not only sheds light on the evolutionary history of ancient animals but also opens new avenues for understanding the origins of avian traits in non-avian species. Future research in this area promises to unravel more mysteries of our planet's distant past.</p>



<p>The full study was published in the journal <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0293021">PLOS ONE</a>.</p>



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Bird tracks discovered that predate the oldest birds by 60 million years

A recently published study reveals fascinating new insights into the...

<p>A study led by the <a href="https://www.uzh.ch/en.html" target="_blank" rel="noreferrer noopener">University of Zurich</a> reveals a concerning gap in the conservation efforts for some of the ocean's most endangered species: <a href="https://www.earth.com/news/sharks-household-products/">sharks</a>, rays, and skates.&nbsp;</p>



<p>These creatures, belonging to the elasmobranch group, are crucial for maintaining the ecological balance in marine environments. However, their survival is at risk due to inadequate protection.</p>



<h2 class="wp-block-heading" id="h-functional-diversity-nbsp">Functional diversity&nbsp;</h2>



<p>The research was focused on the functional diversity of sharks, rays and other elasmobranchs. Functional diversity refers to the various ecological roles these creatures play in their ecosystems.&nbsp;</p>



<p>This aspect of biodiversity, along with taxonomy (species variety) and phylogenetics (evolutionary history), forms a comprehensive understanding of biodiversity.&nbsp;</p>



<h2 class="wp-block-heading" id="h-how-the-research-was-conducted-nbsp">How the research was conducted&nbsp;</h2>



<p>The researchers analyzed a global dataset containing the traits of more than 1,000 elasmobranch species to assess their functional diversity including richness, uniqueness, and specialization.</p>



<p>The analysis pinpointed several critically endangered species that are vital for maintaining the functional diversity of elasmobranchs.&nbsp;</p>



<h2 class="wp-block-heading" id="h-critical-insights-nbsp">Critical insights&nbsp;</h2>



<p>“We identified the top endangered species crucial for maintaining the architecture of elasmobranch functional diversity, including the longfin mako shark, Ganges shark, daggernose shark, shortfin mako shark, and scalloped hammerhead shark,” explained Professor&nbsp; Catalina Pimiento, who led the study.</p>



<p>These species contribute significantly to the intricate tapestry of ecological roles within marine environments.</p>



<h2 class="wp-block-heading" id="h-functional-diversity-hotspots-nbsp">Functional diversity hotspots&nbsp;</h2>



<p>Spatial analysis revealed that the richness of elasmobranch functional diversity is predominantly found along continental shelves and around oceanic islands.&nbsp;</p>



<p>The experts identified 18 unique functional diversity hotspots, which only slightly overlap with those identified by other biodiversity facets.&nbsp;</p>



<p>Study co-author Dr. John Griffin of Swansea University noted that many of these hotspots are under severe threat from industrial fishing.</p>



<h2 class="wp-block-heading" id="h-fishing-pressure-nbsp">Fishing pressure&nbsp;</h2>



<p>“Many of the hotspots vital for elasmobranch biodiversity converge with fishing pressure along the coast of China, others fall around oceanic islands and high seas,” said Dr. Griffin.</p>



<p>"In line with previous global analyses we found that hotspots of fishing pressure are mainly distributed along the coasts of China and Europe (both in the Atlantic and the Mediterranean)," wrote the researchers.</p>



<p>"Smaller fishing pressure hotspots occur on the coasts of the US and Canada and along the Atlantic coast of southern South America (southern Brazil, Uruguay, and Argentina), west Africa and in the Sea of Okhotsk in Russia."</p>



<h2 class="wp-block-heading" id="h-lack-of-protection-nbsp">Lack of protection&nbsp;</h2>



<p>Alarmingly, the study revealed that the multiple facets of elasmobranch biodiversity remain inadequately protected within the global Marine Protected Area network, leaving these species vulnerable to various threats.</p>



<p>"Overall, our results highlight acute vulnerability of the world’s elasmobranchs’ functional diversity and reveal global priorities for elasmobranch functional biodiversity previously overlooked."</p>



<p>The study is published in the journal <a href="http://dx.doi.org/10.1038/s41467-023-43212-3" target="_blank" rel="noreferrer noopener">Nature Communications</a>.</p>



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Sharks need better protection to maintain functional diversity

A study led by the University of Zurich reveals a...

<p>Researchers at the <a href="https://www.port.ac.uk/" target="_blank" rel="noreferrer noopener">University of Portsmouth</a> have discovered that plastic waste in aquatic environments may be severely disrupting the reproductive behavior of <a href="https://www.earth.com/news/more-than-45000-marine-species-are-endangered-by-human-impacts/">marine animals</a>.&nbsp;</p>



<p>The experts say that plastic waste in the water might be stopping - or interrupting - some creatures from reproducing.&nbsp;</p>



<h2 class="wp-block-heading" id="h-studying-marine-plastic-waste">Studying marine plastic waste</h2>



<p>The study was specifically focused on the marine amphipod <em>Echinogammarus marinus</em>, a shrimp-like creature that has a wide distribution.</p>



<p>Previous research on marine plastic pollution has typically examined the physical dangers, such as entrapment and ingestion. Instead, the Portsmouth study explored the chemical composition of <a href="https://www.earth.com/news/plastics-dropped-into-the-ocean-can-travel-hundreds-of-miles-while-sinking/" target="_blank" rel="noreferrer noopener">plastics</a>, particularly the additives that enhance their properties.</p>



<h2 class="wp-block-heading" id="h-unsuccessful-mating-nbsp">Unsuccessful mating&nbsp;</h2>



<p>The study reveals that chemicals commonly found in <a href="https://www.earth.com/news/biodegradable-plastic-materials-do-not-biodegrade-in-the-ocean/" target="_blank" rel="noreferrer noopener">plastics</a> are altering the reproductive behavior of E. marinus. This could have serious consequences not only for the species but also for the entire marine ecosystem.</p>



<p>“This unsuccessful mating behavior has serious repercussions, not only for the species being tested but potentially for the population as a whole," explained Professor Alex Ford from Portsmouth's Institute of Marine Sciences.</p>



<p>"These animals form pairs to reproduce. Once they were exposed to a chemical, they would break apart from their mate and take much longer -in some cases days - to repair, and sometimes not at all."</p>



<p>“These creatures are commonly found on European shores, where they make up a substantial amount of the diet of fish and birds. If they are compromised it will have an effect on the whole food chain.”</p>



<h2 class="wp-block-heading" id="h-widespread-use-of-chemicals-nbsp">Widespread use of chemicals&nbsp;</h2>



<p>The research sheds light on the widespread use of chemicals in everyday products. Out of over 350,000 chemicals used globally, about 10,000 are employed in <a href="https://www.earth.com/news/coral-reef-plastic-pollution-increases-with-depth-and-near-protected-areas/" target="_blank" rel="noreferrer noopener">plastics</a> for various purposes, including flexibility, color enhancement, sun protection, and fire resistance.&nbsp;</p>



<p>Alarmingly, a third of these chemicals are toxic to human health, affecting the immune, nervous, or reproductive systems.</p>



<h2 class="wp-block-heading" id="h-plastic-additives-nbsp">Plastic additives&nbsp;</h2>



<p>The researchers tested four common <a href="https://www.earth.com/news/ocean-plastics-are-a-hazard-at-every-stage-of-their-life-cycle/" target="_blank" rel="noreferrer noopener">plastic additives</a>: phthalates (DEHP and DBP), Triphenyl phosphate (TPHP), and N-butyl benzenesulfonamide (NBBS). These chemicals are found in a range of products, from medical supplies and food packaging to electronic equipment and cooking utensils.</p>



<p>The study revealed that all the tested additives hindered the pairing process of the amphipods, with some even causing a substantial decline in sperm count.</p>



<h2 class="wp-block-heading" id="h-study-implications-nbsp">Study implications&nbsp;</h2>



<p>“Although the animals we tested were exposed to much higher concentrations than you would normally find in the environment, the results indicate these chemicals can affect sperm count," said Professor Ford.</p>



<p>“It is conceivable that if we did the experiment on shrimps that had been exposed for a longer period or during critical stages in their life history, it would affect their sperm levels and quality.”</p>



<h2 class="wp-block-heading" id="h-study-significance-nbsp">Study significance&nbsp;</h2>



<p>Study lead author Bidemi Green-Ojo, a PhD researcher in Environmental Toxicology, emphasized the importance of understanding the effects of these <a href="https://www.earth.com/news/microplastics-found-embedded-in-tissues-of-whales-and-dolphins/" target="_blank" rel="noreferrer noopener">chemicals on aquatic life</a>.&nbsp;</p>



<p>“We must understand more about these chemicals and how they affect behavior. Many types of behavior - such as feeding, fight or flight mode, and reproduction - are essential in an animal's life, and any atypical behavior may reduce the chances of survival," said Green-Ojo.</p>



<p>“We are urging environment agencies around the world to take more notice of behavioral data, because sometimes the data tells us things that normal toxicity tests don’t. Studies like this give a different perspective on potential damage caused by a specific pollutant.”</p>



<p>The study is published in the journal <a href="http://dx.doi.org/10.1016/j.envpol.2023.122946" target="_blank" rel="noreferrer noopener"><em>Environmental Pollution</em></a>.</p>



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Plastic waste is disrupting the sex lives of marine animals

Researchers at the University of Portsmouth have discovered that plastic...

Front,Head,Of,Bottlenose,Dolphin,(tursiops,Truncatus),With,An,Open

<p>Recent research by Tim Hüttner and Guido Dehnhardt from the <a href="https://www.uni-rostock.de/en/" target="_blank" rel="noreferrer noopener">University of Rostock</a>, Germany, has revealed a remarkable discovery about bottlenose dolphins. Known for their intelligence and agility, these marine mammals are now suspected to have an additional sensory ability – the detection of weak electric fields. This finding could revolutionize our understanding of dolphin behavior and sensory capabilities.</p>



<h2 class="wp-block-heading" id="h-studying-bottlenose-dolphins">Studying bottlenose dolphins</h2>



<p>The study began with an observation of bottlenose dolphin calves, which are born with two rows of whiskers on their beaks that eventually fall out, leaving behind vibrissal pits. </p>



<p>Hüttner and Dehnhardt noted that these pits closely resemble the structures in sharks that enable them to detect electric fields. Intrigued by this similarity, they decided to investigate further.</p>



<p>In collaboration with Lorenzo von Fersen at <a href="https://tiergarten.nuernberg.de/en/home.html" target="_blank" rel="noreferrer noopener">Nuremberg Zoo</a> and Lars Miersch at the University of Rostock, Dehnhardt and Hüttner designed experiments to test the dolphins' sensitivity to electric fields. </p>



<p>The team first examined how sensitive two bottlenose dolphins, Donna and Dolly, were to varying electric fields to determine their ability to detect a fish buried in the sandy sea floor. Hüttner, Armin Fritz from Nuremberg Zoo, and a team of colleagues trained the dolphins to rest their jaws on a submerged metal bar. </p>



<p>They then taught them to swim away within 5 seconds upon detecting an electric field from electrodes placed just above their snouts. As the researchers progressively reduced the electric field strength from 500 to 2μV/cm, they meticulously recorded the frequency of the dolphins' correctly timed departures.</p>



<h2 class="wp-block-heading" id="h-what-the-research-team-learned">What the research team learned</h2>



<p>The experiments yielded fascinating results. Donna demonstrated slightly higher sensitivity than Dolly as the electric fields weakened, detecting fields as low as 2.4μV/cm compared to Dolly's threshold of 5.5μV/cm. </p>



<p>The team recognized that living animals produce fluctuating electric fields, not just static ones, due to the pulsing movements of fish gills. To test this, they varied the electric field pulses at 1, 5, and 25 times per second while lowering the field strength. </p>



<p>Both Donna and Dolly detected these pulsing fields. However, their sensitivity to these alternating fields was not as high as it was to steady fields. Dolly detected only the slowest pulsed field at 28.9μV/cm, while Donna sensed all three, with the slowest at 11.7μV/cm.</p>



<h2 class="wp-block-heading" id="h-implications-of-this-super-sense">Implications of this "super sense"</h2>



<p>Dehnhardt explains the practical significance of this finding, stating that the ability to detect weak electric fields aids dolphins in locating fish hidden in sediment. This skill differs from sharks, who can sense electric fields from a greater distance.</p>



<p>Hüttner and Dehnhardt propose that dolphins' ability to perceive electricity might aid them on a larger scale. Dehnhardt explains, "Dolphins could use this sensory ability to orient themselves to the Earth's magnetic field." </p>



<p>He suggests that dolphins swimming at a normal speed of 10m/s through weak areas of the Earth's magnetic field could produce a detectable electric field of 2.5μV/cm across their bodies. Moreover, swimming faster increases their likelihood of sensing the planet's magnetic field, enabling them to navigate globally using an electric sense-based magnetic map.</p>



<p>In summary, this surprising discovery by Hüttner and Dehnhardt opens new avenues for understanding the sensory world of dolphins. It highlights their remarkable adaptability, and also poses exciting questions about the evolutionary purpose and ecological implications of this newfound electrosensitivity "super sense" in dolphins.</p>



<h2 class="wp-block-heading" id="h-more-about-bottlenose-dolphins">More about bottlenose dolphins</h2>



<p>Bottlenose dolphins, scientific name <em>Tursiops truncatus</em>, captivate people worldwide with their intelligence, agility, and playful behavior. These marine mammals, known for their curved mouths giving the appearance of a friendly "smile," belong to the family Delphinidae. They inhabit warm and temperate seas worldwide and have become one of the most studied and recognized dolphin species.</p>



<h3 class="wp-block-heading" id="h-physical-characteristics-of-bottlenose-dolphins">Physical characteristics of bottlenose dolphins</h3>



<p>This dolphin species typically measures between 2 to 4 meters in length and weighs around 150 to 650 kilograms. Their sleek, streamlined bodies, adapted for swimming, display a grayish-blue color with a lighter underside. They possess a distinctive dorsal fin, which provides stability while swimming. These dolphins have a well-developed sense of hearing and eyesight, both above and below the water.</p>



<h3 class="wp-block-heading" id="h-diet-and-hunting-techniques">Diet and hunting techniques</h3>



<p>Bottlenose dolphins are carnivorous, primarily feeding on a diet of fish and squid. They employ sophisticated hunting techniques, including the use of echolocation. By emitting sound waves that bounce off objects, they can locate and identify their prey with remarkable precision. In some regions, they have developed unique hunting strategies, like mud-ring feeding, where they trap fish in muddy circles before feasting on them.</p>



<h3 class="wp-block-heading" id="h-social-behavior-and-communication">Social behavior and communication</h3>



<p>Bottlenose dolphins are highly social animals, living in groups called pods. These pods can contain anywhere from a few individuals to over a dozen. They communicate using a complex array of whistles, clicks, and body language. Each dolphin has a unique signature whistle, functioning like a name, allowing them to call out to specific individuals.</p>



<h3 class="wp-block-heading" id="h-intelligence-and-training">Intelligence and training</h3>



<p>Renowned for their intelligence, bottlenose dolphins can learn and perform complex tasks, making them stars in many aquarium shows. They have the ability to understand symbolic language, use tools, and exhibit problem-solving skills. Researchers continually discover new aspects of their cognitive abilities, deepening our understanding of these fascinating creatures.</p>



<h3 class="wp-block-heading" id="h-reproduction-and-lifespan">Reproduction and lifespan</h3>



<p>Female bottlenose dolphins reach sexual maturity around 5-12 years of age, while males mature a bit later, around 10-12 years. They mate throughout the year, with a gestation period of about 12 months. A calf is born tail-first and quickly rises to the surface for its first breath. Calves typically stay with their mothers for 3-6 years. In the wild, bottlenose dolphins can live up to 40 years or more.</p>



<h3 class="wp-block-heading" id="h-conservation-status">Conservation status</h3>



<p>While bottlenose dolphins are not currently endangered, they face threats from habitat loss, pollution, and fishing nets. Various conservation efforts focus on protecting their natural habitats and reducing human-induced threats. Public awareness and responsible ecotourism play significant roles in the conservation of these magnificent creatures.</p>



<p>In summary, bottlenose dolphins, with their remarkable abilities and charismatic nature, continue to intrigue and delight humans. Their presence in the oceans reminds us of the complexity and beauty of marine life and the importance of preserving such incredible species for future generations.</p>



<p>Understanding and respecting these intelligent creatures is crucial for their continued survival in the ever-changing marine environment.</p>



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Bottlenose dolphins have a newly-discovered 'super sense'

Recent research by Tim Hüttner and Guido Dehnhardt from the...

Dolabrifera nicaraguana

Taxonomic tree: