February 11, 2009. Scientists studying sedimentary rocks in south Oman have discovered high concentrations of steroids that they believe were produced by ancient, multicelluar animals. The team proposes that the fossilized steroids, which date back 635 million years, were produced by sponges, one of the most basic forms of animal life on Earth. Sponges (Phylum Porifera) are a diverse group of aquatic animals, with about 5000 known species worldwide. Sponges are primarily marine creatures but there are also a few species of freshwater sponges.
February 10, 2009. The decline in amphibian populations around the world has caused much concern among biologists and conservationists during recent years. Yet to this point, most of the data documenting amphibian declines has focused on frog populations. Now, a new study offers evidence of salamander population declines as well. A team of biologists from the University of California, Berkeley compared recent salamander population data to population data collected between 1969 and 1978.
February 10, 2009. Scientists studying southern right whales (Eubalaena australis) have discovered that mothers teach their young where to feed. Southern right whales gather off the coast of the Argentina’s Peninsula Valdés between June and December each year. The site serves as a calving ground, with peak calving occurring in August. Females give birth to a single calf once every three years, on average. After about three months, the mother-calf pairs set off for the South Atlantic to feed for the remainder of the year.
February 4, 2009. Researchers from the University of Calgary have revealed that the caribou (Rangifer tarandus) that inhabit Canada's southern Rocky Mountains are unique blend of two distinct caribou lineages. Their work suggests that after the last ice age ended about 10,000 years ago, the receding glaciers left an open corridor that enabled once-isolated populations of caribou to intermix. It is thought that barren-ground caribou migrated southward via this ice-free channel until their range overlapped with the more southerly breed of caribou, the woodland caribou.
February 3, 2009. A fossilized turtle unearthed by geologists working in the Canadian Arctic has shed new light on what the Arctic Ocean was like during the late Cretaceous period, some 90 million years ago. The fossil, named Aurorachelys (or 'aurora turtle'), is believed to be a tropical, freshwater species that originated in Asia. Aurorachelys presented scientists with a puzzle. Here was a tropical species in a polar region, a freshwater turtle in marine habitat, and an Asian turtle in North America.
February 1, 2009. Recent molecular studies have revealed that Zosteropidae—a family of birds commonly referred to as white eyes—diversify into new species faster than any other group of birds. Scientists estimate that every one million years, between 2.24 and 3.16 new species of white eye appears. The Zosteropidae family presently includes more than 100 species and the family is estimated to be between 4.46 and 5.57 million years old.
January 26, 2009. A population study of Asian elephants (Elephas maximus) living in Taman Negara National Park, Malaysia, has revealed that there may be as many as 631 of the endangered elephants in the park—making it the largest known population of the endangered elephants in Southeast Asia. The current range of Asian elephants includes India, Southeast Asia, Sumatra and Borneo. Their former range also included areas south of the Himalayas and China, north to the Yangtze River. Unfortuantely, the species has suffered greatly at the hands of habitat destruction and poaching.
January 13, 2009. Ornithologist Adrienne DuBois, a graduate student from the University of Miami, has discovered that male swamp sparrows modify their song when competing males are nearby. The song of a male swamp sparrow is a slow trill of two or more pitches. Previously, scientists thought that once the swamp sparrow learned its song, it did not modify it—the swamp sparrow simply sang the same tune repeatedly. But DuBois' research shows that swamp sparrows do not sing the same song over and over again. Instead, when competitors are in range, they modify their song—increasing the frequency range and the speed at which they sing.