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Why do whales strand?

Whales that strand individually often appear to be old, sick or injured animals, mass strandings on the other hand, which are usually toothed whales, can include a handful, or at times several hundred animals.

We do not know for certain why these animals strand, but several possible causes have been put forward. Most mass strandings consist of the deep water, toothed whales - odontocete species that are usually found far from shore. It has been suggested that maybe these animals become disorientated when they venture by mistake into shallower waters. Acoustically they are not designed to function in coastal waters and could be confused by echolocation waves received when swimming near gently sloping, sandy shores. Other theories range from fear reactions when being pursued by predators, to poor weather conditions, to herdwide disease. Another possibility lies behind the naturally strong social cohesion and interdependence observed amongst odontocetes. Perhaps the particularly strong social structure finds the group reluctant to leave a sick or injured companion who has ventured to close to shore. Some scientists believe environmental pollution may weaken immune systems, leaving animals vulnerable to disease, which may effect navigation and communication skills. Noise pollution may also play a role by masking acoustic cues.

Learn more in following Odyssey logs:
June 25, 2001
'The Mystery of Whale Strandings'
"Stranding events have been recorded and observed throughout history and have always been considered to be a natural phenomenon. In recent years, strandings resulting in a number of mortalities have affected a number of marine mammal populations. Studies are showing that perhaps not all strandings are as natural as we first thought and that human impact on the marine environment, such as pollution may be playing a significant role.
Listen to the Odyssey log:
Real Audio -  >28k   >64k
'A Sperm Whale Stranding in Darwin'
"Seven years ago, a 50 foot adult male sperm whale, weighing approximately forty tons was washed ashore at Casuarina, one of the Darwin's most popular beaches. Although there is no coordinated network in place to deal with stranded animals of this magnitude, Australian Parks and Wildlife officials did their best to save the dying animal."
Listen to the Odyssey log:
Real Audio -  >28k >64k


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