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An Ancient Biosonar Sheds New Light on the Evolution of Echolocation in Toothed Whales

By Guest PostMay 9, 2013Natureaarhus university, acoustic monitoring, ancient biosonar, aquatic mammals, Bangladesh, biosonar signals, bottlenose dolphin, denmark, earth, evolution of echolocation, evolutionary process, frants havmand jensen, freshwater, freshwater cetaceans, freshwater dolphins, ganges river dolphins, hole, low frequent click, mangrove forest, marine dolphins, marine environments, oceanographic institution, oldest species, peter teglberg madsen, platanistidae family, river habitats, river systems, toothed whales, woods

Some thirty million years ago, Ganges river dolphins diverged from other toothed whales, making them one of the oldest species of aquatic mammals that use echolocation, or biosonar, to navigate and find food. This also makes them ideal subjects for scientists working to understand the evolution of echolocation among toothed whales.

New research, led by Frants Havmand Jensen, a Danish Council for Independent Research | Natural Sciences postdoctoral fellow at Woods Hole Oceanographic Institution, shows that freshwater dolphins produce echolocation signals at very low sound intensities compared to marine dolphins, and that Ganges river dolphins echolocate at surprisingly low sound frequencies. The study, “Clicking in shallow rivers,” was published in the journal PLOS ONE. (more…)

Predators Hunt for A Balanced Diet

By Guest PostJanuary 16, 2012Natureaarhus university, anchomenus dorsalis, ants, aphids, balance of nutrients, balanced diet, beetle larvae, butterfly larvae, calorie content, crickets, denmark, female beetles, food webs, fruit flies, garden insect, grasshoppers, ground beetle, kim jensen, massey university, moths, new zealand, nutritional value, offspring, omnivores, predators, predatory animals, slugs, university of exeter

Predators select their prey in order to eat a nutritionally balanced diet and give themselves the best chance of producing healthy offspring.

A University of Exeter and Oxford-led study published in Proceedings of the Royal Society B shows for the first time that predatory animals choose their food on the basis of its nutritional value, rather than just overall calorie content.

An international team of scientists from the Universities of Exeter and Oxford in the UK, University of Sydney (Australia), Aarhus University (Denmark) and Massey University (New Zealand) based their research on the ground beetle, Anchomenus dorsalis, a well-known garden insect that feasts on slugs, aphids, moths, beetle larvae and ants. (more…)

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An Ancient Biosonar Sheds New Light on the Evolution of Echolocation in Toothed Whales

Predators Hunt for A Balanced Diet