
Dugongs are also known as 'sea cows' because they feed on sea grass and the roots of aquatic plants in sheltered coastal waters.

Sea cliffs are high, rocky coasts that plunge down to the sea's edge. These harsh environments are subject to the battering of waves, wind, and salt-laden sea spray.
Sharks are odd fishes. These sleek predators differ in a number of ways from other fishes and as a result, they are not tucked into the same clade that contains the 20,000-plus species of ray-finned fishes. Instead, sharks branched off from the ray-finned fish lineage some 420 million years ago. The two groups have been forging their own distinct paths ever since.
So what features set sharks apart from the ray-finned fishes? What evolutionary innovations have they come up with in all that time since they diverged from other fish? Here are a few ways sharks differ from other fishes:
Despite these differences, sharks do share a number of characteristics with the ray-finned fishes including the arrangement of their fins and many aspects of their internal anatomy (circulatory, digestive, reproductive, and nervous systems).
Refs: Tricas, T. 1997. Sharks & Rays. New York: Time-Life Books. 288p.
Photo © Engamon / iStockphoto.
When approached by a predator, birds often cry out—they produce what is known as a 'call'. But why would a bird do such a thing? A call draws attention to the caller and might reveal it's location, making it more vulnerable to attack. What is the purpose of such a risky vocal outburst? And when a bird calls out, to whom is the bird communicating? Predators or fellow birds?
A team of scientists from the University of California Davis conducted a series of experiments to find out more about the motives behind bird calls. They caught an assortment of wild birds—dark-eyed juncos, yellow-rumped warblers, house finches. They placed the birds in a birdcage around which they set up a ring of microphones. The researchers then tricked the caged birds into thinking a predator was in their midst by showing showed them a stuffed owl. The calls the birds made in response to the owl's appearance were recorded and analyzed.
Poaching and habitat loss has taken a heavy toll on Siberian tigers in Russia's Far East. The Wildlife Conservation Society conducted a survey of tigers in the region and found a 40 percent decline in their numbers compared to the 12-year average. The monitoring area sampled by the Wildlife Conservation Society covered 9,000 square miles and included 16 monitoring stations. At those monitoring stations, only 56 tigers were counted during the survey.
Conservationists expressed hope that the decline they have revealed will spur action and encourage better protection for the rare cats. According to Dr. Dale Miquelle, of the Wildlife Conservation Society's Russian Far East Program:
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