Dolphins Facts and Information Article Example | Topics and Well Written Essays - 1000 words

Dolphins Facts and Information - Article Example They are also believed to have once lived on land some ten million years ago. According to scientists, dolphins’ skeleton shows that its front flippers are a modified form of hands and the two unattached bones behind its ribcage are pelvic girdles, to which hind limbs once attached (MacGillivray, 2000). Interestingly, dolphins are known for its complex communication which consists of their call ranges, cognitive skills, and ability to modify signals through vocal learning. A study by Janik (2000) revealed how bottlenose dolphin uses whistles that could reach over 580 meters to interact one another. Aside from this, dolphins are known to communicate through sonar which interests auditory researchers, acoustical physics, and even military scientists. In his book â€Å"The Sonar of Dolphins†, Au (1993) documented the abilities to echolocate which means it can explore the depths of the ocean through echo and with little use of sight. With almost forty species, dolphins are known to reach sexual maturity for about six to ten years and copulate from belly to belly through a gestation period which takes up to 11-17 months. After this period, mother dolphins nurse her baby for about a year as female dolphins give birth to one calf every two years. Moreover, when it comes to its sleeping behavior, it is known that dolphins suffocate in full deep sleep and so, they only sleep one half of their brain at a time for about 8 hours a day (Ridgway, 1990). With this, their lifespan could reach a maximum of 40 up to 50 years. Dolphins have long been a fascination for human civilization since the ancient Greek period. These marine mammals are said to have always been friendly to the boaters and bathers at the ancient city of Greece.