One of the most fascinating pursuits in 21st century science is the study of whale songs in Earth’s mighty global ocean. A couple of months ago, we ran a story about sperm whales using clicks to communicate that seem to vary due to culture, for example, not genetics as you might expect. You might also expect whales of the same species in a single part of the ocean to sing songs that are similar. But study from the Wildlife Conservation Society (WCS) – appearing in the January 2012 edition of Marine Mammal Science – now reveals that, while the songs of humpback whales on both sides of the southern Indian Ocean share one similar part or theme, the rest of the themes in the whales’ songs are “almost completely different.”

You can hear some of the songs in the audio above. I wish the WCS had provided more information about this audio clip, but they didn’t. I think what’s going on here is that we’re hearing two different sorts of songs from whales on both sides of the southern Indian Ocean, specifically near Madagascar and Western Australia. They did say that males humpbacks are most often the singers, and they sing most often on the whales’ winter breeding grounds, migratory routes, and summer feeding grounds. The songs themselves are:

… complex arrangements of parts or “themes,” consisting of ascending and descending wails, moans, and shrieks that are repeated in cycles lasting up to 30 minutes. The transmission of songs between individuals from different populations is likely to occur on feeding grounds or during migration when whales from different populations mix. Or, transmission of song may occur when individual male “troubadours” travel to different breeding grounds between breeding seasons or possibly during the same breeding season.

What are whales talking about? Help find out

Humpback whales. Image Credit: NOAA

The results of the WCS study – conducted with Columbia University and with researchers in Australia – contradict previous humpback whale song comparisons. When songs from populations in the same ocean basins are compared, researchers usually find the songs containing several or many similar parts or themes. This study shows only one common theme for humpbacks in the southern Indian Ocean, while other parts of the songs varied.

The researchers say the differences in songs between Indian Ocean humpback populations probably indicate a limited exchange between the two part of the ocean. They might shed new light on how whale culture spreads.
Lead author of the study – Anita Murray, who conducted the research while a graduate student at Columbia University and the Wildlife Conservation Society and who is now pursuing her doctorate at the University of Queensland in Australia – said:

In the Northern Hemisphere, within an ocean basin whales sing songs that are composed of the same themes. However, whales in the southern Indian Ocean are singing almost completely different songs … The reason for this anomaly remains a mystery. It could be the influence of singing whales from other ocean basins, such as the South Pacific or Atlantic, indicating an exchange of individuals between oceans which is unique to the Southern Hemisphere.

Read more about this story from EurekAlert

Study finds evidence of sperm whale culture

For decades, scientists have been listening to whales and dolphins, trying to understand what they’re saying. Now, the public — people like you and I — are being invited to work with them in a unique new research project called Whale FM. Over 16,000 recorded vocalizations by Killer whales and Pilot whales await analysis. Volunteers are needed to listen to whale call audio segments, to identify similar-sounding calls from different individuals. This work will help scientists characterize different types of calls, taking us a few steps closer to understanding whale conversations.

Study finds southern Indian Ocean humpbacks singing different tunes

Whale FM is the latest citizen science project at Zooniverse, created in collaboration with Scientific American, Woods Hole Oceanographic Institution in Massachusetts, and the Sea Mammal Research Unit (SMRU) at the University of St. Andrews in Scotland.

Pilot whale. Image credit: Barney Moss via Wkimedia Commons

In a press release announcing the Whale FM project, its principal scientist, Peter Tyack of the University of St. Andrews, said,

Only a few researchers have categorized whale calls. By asking hundreds of people to make similar judgments, we will learn how reliable the categories are, and they get the fun of hearing these amazing sounds.

Past research in categorizing calls have revealed that Killer whales have a diverse repertoire that’s used for communication, navigation, and feeding. Scientists were surprised to find that different Killer whale pods have their own “dialects.” Much less is known about Pilot whales; the researchers who created Whale FM hope to harness the collective efforts of citizen scientists to better understand what Pilot whales are saying to each other.

D-Tag on a Pilot whale. Image credit: Whale FM

Many of the whale call recordings were obtained using ”D-Tags,” temporary tags that are suction-cupped to the base of a whale’s dorsal fin. Each tag is equipped with a hydrophone (underwater microphone) that records vocalizations of its host whale and other nearby whales, as well as motion sensors that record underwater activities such as dive depths. Whales are not harmed by these non-invasive tags that are designed to detach after about 30 minutes.

A hydrophone array deployed at sea. Image Credit: Whale FM.

Scientists also use hydrophone arrays, that’s several hydrophones strung together, to eavesdrop on whales. The arrays, deployed from ships or connected to buoys, pick up all sounds in the ocean. Specialized software processes these sounds to isolate whale calls, even determining the direction of the calls. In some instances, information about the location of a calling whale and it movements can be extracted from the hydrophone array data.

For volunteers, the hub of this project is the Whale FM website. There, they’re presented with a recorded call and a map showing the whale’s location at the time of the recording. Volunteers are asked to listen to other recordings, displayed below the main whale call audio clip, to determine if any of them sound similar to the main call. Similar-sounding calls are flagged by the volunteer and stored for further analysis by scientists. (If you decide to give it a try, I highly recommend reviewing their tutorial to familiarize yourself with the nuances of whale calls.)

Whales and dolphins have a diverse repertoire of calls for communicating with others of their kind. But what are they saying? With the help of volunteers combing through the voluminous data of Killer whale and Pilot whale vocalizations, call patterns will begin to emerge, allowing scientists to determine the extent of the “vocabulary” for each species, including population-related dialects.

The secret language of sperm whales

Study finds evidence of sperm whale culture

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Amazing video of twirling whale

Humpback whales make bubble nets with beauty and precision

Dolphins create a two-dimensional sound beam

300 humpback whales found gorging on krill in Antarctic bays

Changing songs of humpback whales cause cultural ripples across an ocean

52-Hertz song of world’s loneliest whale

John Hildebrand on blue whale songs’ lower pitch

According to some media reports and scientific publications, jellyfish are becoming more common and might dominate the Earth’s oceans in coming decades. Jellyfish blooms are clogging fishermen’s nets, stinging swimmers, and even choking intake lines for power plants The reason, some suggest, is the increasing human impact on the planet’s oceans, including overfishing and climate change.

Moon jellyfish beach are stranding in San Francisco in November 2010. Image Credit: Ocean Beach Bulletin

But are jellyfish really taking over the world’s oceans? Not necessarily, according to a study in the February 2012 issue of BioScience. The researchers suggest that claims of an increase in jellyfish blooms around the world are not supported with any hard evidence or scientific analyses, but instead might be the result of more scientific attention and media fascination with the topic.

The report also points to the lack of good information on jellyfish blooms in the past, which encourages misleading comparisons. According to the report, the available fossil and documentary evidence indicates that occasional spectacular blooms of jellyfish are a normal part of such organisms’ natural history, and may be linked to natural climate cycles, but drew less attention in decades and centuries gone by.

Giant jellyfish clog fishing nets in Japan. Photo credit: Shin-ichi Uye

The report’s authors do not urge complacency, however, and acknowledge a lack of consensus among researchers. They point out that changes in populations of jellyfish and similar sea organisms do have important consequences for local marine ecology and could be affected by human activity. For that reason, they are assembling a comprehensive new database that will enable trends in the numbers of such creatures to be assessed and the links to human activity studied. But for now, Condon and his coauthors believe the case for jellyfish-dominated seas in coming decades is not proven.

The study was led by Rob Condon, marine scientist at the Dauphin Island Sea Lab in Alabama. Condon’s co-authors are comprised of experts from the Global Jellyfish Group, a consortium of approximately 30 experts on gelatinous organisms, climatology, oceanography, and socioeconomics from around the globe.

Bottom line: A study in the February 2012 issue of BioScience suggests that claims of an increase in jellyfish blooms around the world are not supported with any hard evidence or scientific analyses, and instead might be the result of more scientific attention and media fascination with the topic.

Read more from AIBS Bioscience

Conservationists working in Central Africa to save the world’s rarest gorilla have good news: the Cross River gorilla has more suitable habitat than previously thought, including vital corridors that, if protected, can help the great apes move between sites in search of mates, according a habitat analysis published in early 2012.

A recent study by the Wildlife Conservation Society, the North Carolina Zoo, and others used satellite imagery to study the Cross River gorilla's habitat -- the mountainous border region between Nigeria and Cameroon.Image Credit: Aaron Nicholas/Wildlife Conservation Society

The Cross River gorilla is the rarest of the four subspecies of gorilla, numbering fewer than 300 individuals across its entire range, limited to the forested mountainous terrain on the border region of Nigerian and Cameroon. The subspecies is listed as “Critically Endangered” and is threatened by both habitat disturbance and hunting, as the entire population lives in a region of high human population density and heavy natural resource exploitation.

Cool video: Man meets mountain gorillas

The habitat analysis, by researchers from the North Carolina Zoo, the Wildlife Conservation Society (WCS), and other groups, used a combination of satellite imagery and on-the-ground survey work. The researchers say that the analysis will help guide future management decisions for Cross River gorillas living in the mountainous border region between Nigeria and Cameroon.

The Cross River gorilla, the most endangered great ape in Africa, is seen here in Cameroon's Limbe Wildlife Center. Images of wild Cross River gorillas are rare, due to the rugged terrain in which they exist and the great ape's elusive behavior. Image Credit: Nicky Lankester

WCS conservationist and co-author Andrew Dunn said:

The good news for Cross River gorillas is that they still have plenty of habitat in which to expand, provided that steps are taken to minimize threats to the population.

Using high-resolution satellite images, the research team mapped the distribution of forest and other land-cover types in the Cross River region. In order to ground truth the land-cover map, field researchers traveled to more than 400 control points to confirm its accuracy.

With the new habitat suitability map to guide them, the team selected 12 locations possessing all the characteristics of gorilla habitat (mainly forested landscapes far from human settlements) for field surveys. Most of these areas had no previous record of gorillas, but to their surprise, the team found signs of gorilla presence (in the form of gorilla dung and nests) in 10 of the 12 sites, thereby confirming the value of using satellite image analysis to predict suitable habitat and to prioritize areas in which to conduct further surveys.

Overall, the findings of the study represent a significant expansion of known Cross River gorilla range. The area now known to be occupied by gorillas is more than 50 percent larger than had previously been documented.

The study also located parts of the population under threat from isolation through fragmentation. For example, Afi Mountain Wildlife Sanctuary in Nigeria, which contains a significant portion of the Cross River gorilla population, is only tenuously connected to the nearest sub-population of gorillas by farmland and other forms of habitat degradation. WCS researcher Inaoyom Imong said:

For small populations such as this one, the maintenance of connective corridors is crucial for their long term survival. The analysis is the first step in devising ways to rehabilitate degraded pathways.

Bottom line: A habitat analysis by researchers from the North Carolina Zoo, the Wildlife Conservation Society (WCS), and other groups says that the Cross River gorilla – world’s rarest gorilla – has more suitable habitat than previously thought. The habitat includes vital corridors that, if protected, can help the great apes move between sites in search of mates.

Via EurekAlert

Watch this amazing video of a man’s amazing chance encounter with a troop of wild mountain gorillas near Bwindi National Park, Uganda.

He’s wide-eyed and beaming with joy.

Good news for world’s rarest gorilla

Researchers have identified a new species of prehistoric crocodile. The extinct creature, nicknamed “Shieldcroc” due to a thick-skinned shield on its head, is an ancestor of today’s crocodiles. The discovery was published in the journal PLoS-ONE in February 2012.

Shieldcroc is the newest discovery of crocodile species dating to the Late Cretaceous period, approximately 95 million years ago. This period is part of the Mesozoic Era, which has been referred to as the “Age of the Dinosaurs;” however, numerous recent discoveries have led to some scientists calling the era the “Age of the Crocs,” according to Casey Holliday, co-researcher and assistant professor of anatomy in the University of Missouri School of Medicine.

Researchers analyzed a portion of a fossilized crocodile skull to identify a new species, Shieldcroc. Analyzing scarring and ridges on the skull, he identified a thick-skinned “shield” on top of the skull. Image Credit: Casey Holliday/University of Missouri

Holliday identified Shieldcroc by studying a fossilized partial skull specimen, which was discovered in Morocco and held by the Royal Ontario Museum of Toronto for several years before Holliday analyzed it. By analyzing blood vessel scarring on the bone, Holliday determined that the crocodile would have had a structure on top of its head, resembling a shield. The dents and bumps on the bone indicate veins delivered blood to a circular mound of skin, something never before seen in a crocodile. He said the shield was likely used as a display structure to attract mates and intimidate enemies and possibly as a thermo-regulator to control the temperature of the animal’s head.

Holliday compared Shieldcroc’s skull to those of other crocodilians. By comparing slopes of various bones, he found that the new species had a flatter skull than other known species. With this information, he believes it is unlikely that Shieldcroc wrestled dinosaurs on or near the shoreline. Instead, Holliday said the fossil indicates that Shieldcroc had thin jaws, likely used to catch fish.

Co-author Nick Gardner is an undergraduate researcher at Marshall University. He said:

We believe Shieldcroc may have used its long face as a fish trap. It is possible that it lay in wait until an unsuspecting fish swam in front of it. Then, if it was close enough, Shieldcroc simply opened its mouth and ate the fish without a struggle, eliminating the need for strong jaws.

Image Credit: Henry Tsai/University of Missouri

In addition, Holliday analyzed Shieldcroc’s skull and brain to estimate the overall size of the reptile. He said scientists often use head size of an animal to estimate its total length. Using several parameters, Holliday and Gardner estimate that this specimen had a five foot long head and was 30 feet long.

Although Shieldcroc lived more than 90 million years ago, Holliday said scientists can use information about the animal to gain a better understanding of today’s crocodiles.

Today’s crocodiles live in deltas and estuaries, the environments put under the most stress from human activity. By understanding how these animals’ ancestors became extinct, we can gain insight into how to protect and preserve the ecosystems vital to modern crocodiles.

Bottom line: Researchers have identified a new species of crocodile dating to the Late Cretaceous period, approximately 95 million years ago. They extinct animal, nicknamed “Shieldcroc” due to a thick-skinned shield on its head, is an ancestor of today’s crocodiles. The discovery was published in the journal PLoS-ONE in February 2012.

Via EurekAlert

Snowy owl sightings have soared in the lower 48 states of the U.S. this year, the news agency Reuters said on January 28, 2012.

Copyright Warner Brothers

In Northern Hemisphere winter of 2012, thousands of birders have reported seeing the beautiful Arctic white owls, known to many in the fictional books of Harry Potter as the magical familiar Hedwig.

Denver Holt, head of the Owl Research Institute in Montana, has studied snowy owls in their Arctic tundra ecosystem for two decades. He told Reuters:

What we’re seeing now – it’s unbelievable.

This is the most significant wildlife event in decades.

Snowy owl sightings have soared in Northern Hemisphere winter 2012. (USFWS)

For the real snowy owls, researchers say the drive for food is likely behind their increased migrations south. They observed that snowy owls have hatched unusually large clutches last season, up to seven owl chicks compared to the more normal two.

An abundance of their favorite food, rodents and lemmings in particular, yielded the large clutches. The younger owls, mostly male, have migrated south throughout 2012 to avoid competition. More snowy owls migrating has led to the increased sightings. Wildlife experts report the owls are often found malnourished and in poor health from these extended migrations.

Snowy owls aren't in Kansas anymore, according to reports early 2012. (USFWS)

Bottom Line: Snowy owl sightings have soared in the lower 48 states of the U.S. in early 2012, spurred on by a booming population and lack of food in their Arctic habitat.

Lifeform of the week: Hoatzins are odd birds

New research has combined scientific observations with Canadian Inuit traditional knowledge to how killer whales (Orcinus orca) in the Arctic eat and behave. Researchers from Manitoba visited 11 Canadian Nunavut Inuit communities and collated information from over 100 interviews with hunters and elders as part of this research. They published their results on January 29, 2012 in the open access journal Aquatic Biosystems, saying that the increase in hunting territories available to killer whales in the Arctic due to climate change and melting sea ice could “seriously affect the marine ecosystem balance.”

Transient killer whales near Unimak Island, eastern Aleutian Islands, Alaska. They are top predators that affect the behavior of their prey, causing them to run away, dive deep or try to hide among sea ice. Image Credit: Wikimedia Commons

Killer whales are top marine predators wherever they are found. According to these researchers, the whales “seem to eat everything from schools of small fish to large baleen whales, over twice their own size.” “Aarlirijuk,” or the fear of killer whales, apparently influences the behavior of killer whales’ prey. Smaller mammals seek refuge in shallow waters or on shore, and larger prey run away, dive deep, or attempt to hide among the ice. Even narwhal, which are capable of stabbing a killer whale with their tusks (although this is likely to result in the deaths of both animals), will run to shallow waters and wait until the whales give up.

The type of reported prey varied between areas. Most incidences of killer whales eating bowhead whales occurred in the Arctic’s Foxe Basin, while narwhal predation was more frequent around Baffin Island.

Inuit were also able to describe first-hand how killer whales hunted, including several reports of how killer whales co-operated to kill the much larger bowhead. During the hunt some whales were seen holding the bowhead’s flippers or tail, others covering its blowhole, and others biting or ramming to cause internal damage. Occasionally dead bowheads, with bite marks and internal injuries but with very little eaten, are found by locals.

Even narwhal, which are capable of stabbing a killer whale with their tusks (although this is likely to result in the deaths of both animals), will run to shallow waters and wait until the whales give up. Image Credit: Wikimedia Commons

Click here to expand image above

In this research, the Inuit who were consulted about the diets of killer whales reported that killer whales would ‘eat whatever they can catch’, mainly other marine mammals including seals (ringed, harp, bearded, and hooded) and whales (narwhal, beluga and bowhead).

However there was no indication that Arctic killer whales ate fish. Only seven of the interviewees suggested that killer whales ate fish, but none of them had ever seen it themselves.

Arctic killer whales. Image Credit: Dr. Steven Ferguson

Killer whales have recently started colonizing Hudson Bay (possibly due to loss of summer sea ice with global warming). Local communities are reliant on the very species that the orcas like to eat. Dr Steven Ferguson from the University of Manitoba who led this research commented, “Utilizing local knowledge through TEK will help scientists understand the effects of global warming and loss of sea ice on Arctic species and improve collaborative conservation efforts in conjunction with local communities.”

Bottom line: Killer whales in the Arctic, which are top predators, eat a variety of foods and influence the behavior of their prey, according to a new study led by Dr. Steven Ferguson from the University of Manitoba, published January 29, 2012 in the open access journal Aquatic Biosystems. If, as scientists expect, climate continues to warm, the whales will affect marine ecosystems different from those they now inhabit. For example, the whales have started colonizing Hudson Bay in recent years, where local communities are dependent on the species orcas like to eat.

Via EurekAlert

Males house mice sing songs of individuality and kinship to attract mates, according to a paper in the journal Physiology & Behavior in January 2012. These mice melodies are in the ultra-sonic range, so human ears can’t detect them. Researchers at the University of Veterinary Medicine, Vienna used spectrographic analyses to learn what type of information is contained in males’ songs for the discerning ear of the female mouse to detect.

It has been known that house mice produce ultrasonic vocalizations (USVs) during courtship, but it has generally been assumed that these are no more than squeaks. However, the spectrographic analyses revealed that USVs are complex and show features of song. Although the vocalizations are inaudible to human ears, when playbacks of recorded songs are slowed down their similarity to bird song becomes striking.

The study song confirmed that males emit songs when they encounter a female’s scent and that females are attracted to males’ songs. Additionally, the scientists discovered that females are able to distinguish siblings from unrelated males by their songs – even though they had previously never heard their brothers sing.

Image Credit: 4028mdk09

The researchers used digital audio software to examine parameters of the songs, such as duration, pitch and frequency. They found that males’ songs contain “signatures” or “fingerprints” that differ from one individual to another. Moreover, they confirmed that the songs of siblings are very similar to one another compared to the songs of unrelated males, which helps explains how females can distinguish unrelated males.

Who knew baby rhinos sounded like this?

Interestingly, in some species of birds the males with the most complex songs appear to be most successful at attracting females. Further studies are needed to determine whether the complexity of male mouse vocalizations has an effect on females that is similar to that of “sexy syllables” in birds.

Image Credit: 4028mdk09

The vocalizations of wild house mice differ significantly from those of inbred strains of laboratory mice. Wild male mice produce more syllables within high frequency ranges than laboratory mice, a result that is consistent with other studies that find genetic effects on mouse song.

Ravens gesture to each other with their beaks

Bottom line: Males house mice sing songs of individuality and kinship to attract mates, according to a paper in the journal Physiology & Behavior in January 2012. These mice melodies are in the ultra-sonic range, so human ears can’t detect them. However, spectrographic analyses revealed that the mice vocalizations are complex and show features of song.

Via University of Veterinary Medicine Vienna

A dog skull unearthed in a Siberian cave presents some of the oldest known evidence of dog domestication and suggests modern dogs may be descended from multiple ancestors.

A St. Bernard sure does look different from a dachshund ... and new evidence suggests that today's dogs might have originated from more than one ancient ancestor, contrary to what some DNA evidence previously has indicated. Photo credit: Soggydan

The ancient skull, preserved in a cave in the Altai Mountains of Siberia for 33,000 years, presents some of the oldest known evidence of dog domestication and, together with equally ancient dog remains from a cave in Belgium, indicates that domestication of dogs may have occurred repeatedly in different geographic locations rather than with a single domestication event.

Wild dogs didn’t go extinct in East Africa after all

In other words, today’s dogs might have originated from more than one ancient ancestor, contrary to what some DNA evidence previously has indicated.

'wolves have long thin snouts and their teeth are not crowded,' said Hodgins. Photo credit: Tambako the Jaguar

Greg Hodgins, a researcher at the University of Arizona’s Accelerator Mass Spectrometry Laboratory is co-author of the study that reported the find. He said:

Both the Belgian find and the Siberian find are domesticated species based on morphological characteristics. Essentially, wolves have long thin snouts and their teeth are not crowded, and domestication results in this shortening of the snout and widening of the jaws and crowding of the teeth.

The Altai Mountain skull is extraordinarily well preserved, said Hodgins, enabling scientists to make multiple measurements of the skull, teeth and mandibles that might not be possible on less well-preserved remains. Hodgins said:

The argument that it is domesticated is pretty solid. What’s interesting is that it doesn’t appear to be an ancestor of modern dogs.

The researchers used radiocarbon dating to determine the age of the Siberian skull. They determined that the Siberian skull predates the last great ice age, which occurred between 26,000 and 19,000 years ago. Because the ice sheets severely disrupted life for humans and animals during this time, Hodgins believes neither the Belgian nor the Siberian lineages survived the severe conditions.

Image Credit: Nikolai D. Ovodov

However, the two skulls indicate that the domestication of dogs by humans occurred repeatedly throughout early human history at different geographical locations, which could mean that modern dogs have multiple ancestors rather than a single common ancestor. Hodgins said:

Typically we think of domestication as being cows, sheep and goats, things that produce food through meat or secondary agricultural products such as milk, cheese and wool and things like that.

Those are different relationships than humans may have with dogs. The dogs are not necessarily providing products or meat. They are probably providing protection, companionship and perhaps helping on the hunt. And it’s really interesting that this appears to have happened first out of all human relationships with animals.

Bottom line: A dog skull, preserved in a cave in the Altai Mountains of Siberia for 33,000 years, presents some of the oldest known evidence of dog domestication and, together with equally ancient dog remains from a cave in Belgium, indicates that domestication of dogs may have occurred repeatedly in different geographic locations rather than with a single domestication event.

Via EurekAlerts