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Older Male Sparrows Not Threatened by Younger Males

2012-02-15T14:57:05Z

Older male white-crowned sparrows don't see younger male sparrows as much of a threat. When vying for mates or squabbling over territory, older males don't often bother challenging their younger rivals because they pose little credible competition. Instead, they only pick a fight with other older males that could pose a significant threat to their superiority.

It turns out, the way these birds figure out each others' seniority is based on their songs as well as their plumage. Male white-crowned sparrows use song for multiple purposes including attracting a mate and claiming their territory. Since young male white-crowned sparrows sing differently than older males, song can be used to distinguish age.

After mapping the territories of 16 male white-crowned sparrows, the research team was able to observe how males of different ages responded to songs made by intruders.

They found that older birds did nto react as strongly when they heard the song of a younger bird in their territory.

Photo © Douglas Nelson / Ohio State University

Older Male Sparrows Not Threatened by Younger Males originally appeared on About.com Animals / Wildlife on Wednesday, February 15th, 2012 at 14:57:05.

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Tiny Tarsier Produces Ultrasonic Calls

2012-02-13T16:27:13Z

Scientists have discovered that tarsiers, a group of tiny primates native to Southesast Asia, produce ultrasonic calls that are well beyond the audible range of humans. The frequency of the tarsirs' calls is among the most extreme of all animals, and is comparable to the ultrasonic calls made by dolphins and bats. The team of scientists, led by Nathaniel Dominy of Dartmouth, focused their study on a species of tarsier native to the Phillipines.

Tarsiers are a group of primates that diverged from monkeys and apes some 60 million years ago. The group has changed little during the past 45 million years and are considered to be living fossils. They measure a mere 5 inches from head to tail and live on a diet of small animals such as insects and reptiles.

Dominy and colleages noticed that the that tarsiers of Borneo and the Philippines were quieter than species elsewhere. This observation led them to inquire whether the vocalizations of the Borneo and Philippine tarsiers were outside the range of human hearing. They recorded sounds of 35 wild tarsiers on special equipment that captures sounds well outside the range of human hearing. They discovered that the tarsiers were producing ultrasonic calls that were otherwise similar to calls produced by tarsier species that call in the audible range. Further tests showed that tarsiers could indeed hear the ultrasonic calls.

Their findings reveal that tarsiers can both send and receive vocal signals in the ultrasonic range.

Photo © Nathaniel Dominy / Dartmouth.

Tiny Tarsier Produces Ultrasonic Calls originally appeared on About.com Animals / Wildlife on Monday, February 13th, 2012 at 16:27:13.

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Rare Bird Rediscovered in China

2012-02-07T15:14:06Z

In the late 1800s and early 1900s, a reclusive species of bird was discovered in China. The bird, given the common name of "blackthroat", was rarely sighted for over a century after its initial discovery. Now scientists working in the Quinling Mountains in Shaanxi Province in north central China have announced the rediscovery of a breeding site of blackthroats nestled in the dense bamboo, coniferous and broadleaf forests that blanket the mountain slopes above 2400 meters.

The research team, which included scientists from China and Sweden, discovered seven males in Foping National Nature Reserve. An additional seven males were located in Changquing National Nature Reserve.

Blackthroats (Luscinia obscura) bear some resemblence (size and shape) to European robins. But instead of a rusty red breast, blackthroats have a jet blakc throat and breast. Females are thought to have a brown throat and breast, but so far only males of the species have been definitely identified.

The species is classified as vulnerable according to the IUCN Red List due to its small and presumably declining population. It faces threats from habitat destruction as a result of widespread logging and agricultural land use throughout its range.

Photo © Per Alström / Foping National Nature Reserve, Shaanxi, China.

Rare Bird Rediscovered in China originally appeared on About.com Animals / Wildlife on Tuesday, February 7th, 2012 at 15:14:06.

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Arachnid Pictures

2012-01-27T12:51:54Z

Arachnids are more than just spiders. Browse our new Arachnid Pictures to get a close-up glimpse of arachnid diversity.

Arachnid Pictures originally appeared on About.com Animals / Wildlife on Friday, January 27th, 2012 at 12:51:54.

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Sea Turtles Coping with Climate Change

2012-01-25T22:33:59Z

The gender of a baby green sea turtle is determined by the temperature the egg experiences during incubation. When temperatures are warmer, more females are born while. Conversely, when temperatures are cooler, more are males born.

This means that if climate change causes temperatures to rise, sea turtles risk having populations that are composed of nearly all females. If this happens, they may experience a reduction in genetic diversity since few males will be available with which to breed.

Scientists from the University of Exeter, University of Lefke (Turkey) and North Cyprus Society for Protection of Turtles have been studying green sea turtles in Northern Cyprus to assess how diverse the population is and to estimate the impact rising temperatures have had on the turtles thus far.

The research team conducted genetic tests and found that, counter to what they had expected, the green sea turtle population was surprisingly diverse. The data enabled them to estimate how many males were mating with nesting females in the population and they found that there was an average of 1.4 males for every female. Satellite tracking data revealed that males swim vast distances, sometimes thousands of miles during a single breading season. This means that males could be mating between populations that were previously thought to be more genetically isolated.

The study offers hope for sea turtles in the face of the uncertainties posed by climate change. Although rising temperatures remain a threat to sea turtles, there is cause for optimism that green sea turtles can cope with fluctations in temperature better than expected.

Photo © Kimberley Stokes / University of Exeter.

Sea Turtles Coping with Climate Change originally appeared on About.com Animals / Wildlife on Wednesday, January 25th, 2012 at 22:33:59.

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Crustaceans - Mobile Swiss Army Knives

2012-01-25T16:11:41Z

Crustaceans are one of four basic groups of arthropods (the other three being the myripods, arachnids and insects). The group includes crabs, lobsters, shrimp, krill, crayfishes, wood lice and barnacles.

Crustaceans are by no means as diverse in species number as the insects or even the arachnids, but they do come in a mind-boggling array of shapes and sizes. Since crustaceans are with few exceptions aquatic species, they have escaped the demands of life on land (demands which place limitations on the ornateness of body form that can develop).

Crustaceans are an old group of animals, dating back some 500 million years to the Cambrian. Their body plan is simple yet elegant and adaptable. In his book, The Variety of Life, Colin Tudge likens crustaceans to mobile Swiss Army knives—composed of up to 32 segments each equipped with its own pair of appendages that are modified for a variety of tasks: locomotion, defense, communication, feeding, hunting, reproduction. Each segment and its appendage is like a separate tool and together the segments and appendages form as well-adapted a tool kit as a Swiss Army knife.

Photo © Ben Cranke / Getty Images.

Crustaceans - Mobile Swiss Army Knives originally appeared on About.com Animals / Wildlife on Wednesday, January 25th, 2012 at 16:11:41.

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Arachnids - Not Simply Spiders

2012-01-25T13:29:32Z

Although scientists don't know exactly how many species of arachnids there are alive today, their best guess puts the species count in the ballpark of 100,000 of which, more than 40,000 are spiders. Since that means nearly half of all archnids are spiders, it's easy to forget the other lesser-known eight-legged creatures that belong to the group.

Arachnids include about a dozen subgroups, many of which are obscure groups that most people have never heard of. But there are a few that stand out. The most well-known group is of course, the spiders. But odds are you've probably also heard of a few other arachnid groups. They include: harvestmen, ticks and mites, and scorpions.

Scorpions are easy to recognize thanks to their segmented tails that curl up to a venomous point. Ticks and mites are generaly very small, measuring just a few millimeters in length. Harvestmen are perhaps the group that is most commonly mistaken for spiders. There are about 6,300 species of harvestmen (also known as daddy-long-legs). Members of this group have very long legs and their abdomen and cephalothorax are almost completely fused.

So next time you see something with eight legs, don't immediately assume it's a spider.

Photo © Steve Taylor / Getty Images.

Arachnids - Not Simply Spiders originally appeared on About.com Animals / Wildlife on Wednesday, January 25th, 2012 at 13:29:32.

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Rare Langur Discovered in Borneo

2012-01-21T20:43:21Z

Scientists have discovered a previously unknown population of Miller's grizzled langurs (Presbytis hosei canicrus), an endangered primate thought to be on the verge of extinction. The rare langurs were discovered in the Wehea Forest of East Kalimantan, Borneo. Wehea Forest is a 38,000 hectare patch of undisturbed rainforest that is home to nine species of primates including gibbons and the Bornean orangutan.

Since 2004, scientists have been concerned that Miller's grizzled langurs had become extinct. A survey conducted in 2008 found none of the langurs, further supporting the possibility that the species had become extinct. Fortunately, camera traps set up in areas west of the Miller's grizzled langur's range revealed that the species was still living.

Since the Wehea Forest is remote, it presents challenges for scientists hoping to study the animals that inhabit the area. Consequently, not much is known about Miller's grizzled langurs. Any effort to protect the species will be clouded by a lack of knowledge and understanding of the species habits and even their range.

Rare Langur Discovered in Borneo originally appeared on About.com Animals / Wildlife on Saturday, January 21st, 2012 at 20:43:21.

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Thailand's Anti-Poaching Efforts Paying Off

2012-01-17T16:02:28Z

Anti-poaching efforts are successfully helping to protect many rare species in Thailand, according to a recent report by the Wildlife Conservation Society (WCS). Videos and images collected from WCS camera traps provide park rangers much needed data that can be used to arrest and convict poachers. Additionally, camera trap information is used by Wildlife Conservation Society scientists to measure and track population sizes of numerous local species.

The camera traps, placed in multiple locations within Thailand's Western Forest Complex, have capture footage and pictures of a variety of species including wild pigs, leopards, tigers, gaurs, Asian elephants, sun bears, clouded leopards, banteng and many others. Camera trap data indicates that there are between 125 and 175 tigers living within the 18,000-square kilometer Western Forest Complex.

Thailand serves as a critical front in the battle against poachers. The WCS has joined forces with the Thai government to train park rangers how to protect the region's rare animals from illegal hunting. Many park rangers and wildlife guards from other Asian countries are trained in Thailand, so they can learn how to best protect the rare wildlife from poaching in their own countries.

Photo © DNP-Government of Thailand / WCS Thailand Program. Camera trap image of an Asian elephant calf in a heard of adults, photographed in the Western Forest Compex, Thailand.

Thailand's Anti-Poaching Efforts Paying Off originally appeared on About.com Animals / Wildlife on Tuesday, January 17th, 2012 at 16:02:28.

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New Viper Discovered in Tanzania

2012-01-17T12:19:51Z

Scientists working in the remote montane forests of southern Tanzania have recently discovered a new species of viper. The new snake, named after the daughter of one of the scientists involved in the discovery, is called the Matilda's horned viper (Atheris matildae).

The discovery was made by a team of experts that included Michele Menegon of Museo delle Scienze of Trento, Italy, Tim Davenport of the Wildlife Conservation Society and Kim Howell of the University of Dar es Salaam.

Matilda's horned viper is similar to (and larger than) the Usambara bush viper (Atheris ceratophora). Genetic analysis has revealed that the two species diverged about 2.2 million years ago.

Scientists expect the Matilda's horned viper to be classified as critically endangered by the IUCN due to the species' restricted range. It is thought that the Matilda's horned viper survives within a fragment of montane forest no larger than 100 square kilometers.

Since illegal wildlife trade presents a serious threat to many reptiles in the region, the exact location of the new snake's habitat has not been publicized.

New Viper Discovered in Tanzania originally appeared on About.com Animals / Wildlife on Tuesday, January 17th, 2012 at 12:19:51.

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