Due to intensive hunting, the size of sperm whales decreased dramatically, mainly because the larger males were killed first and most intensely, as they were richer in spermaceti. In the Nantucket museum there is a sperm whale jaw, 5.5m long.
The mandible grows to reach 20-25% of the total length of the sperm whale. So this whale may have been 28m long and weighed around 150 tons. Another evidence of the great males of the past is found at the New Bedford museum and is a jaw, 5.2m long, of a male which may have measured around 25.6 meters in length and had a mass of around 120- 130 tons.
Today male sperm whales usually do not exceed 18 m in length and 52 tons in weight. The largest sperm whales ever observed were comparable in size to the fin whale, making the sperm whale the second or third largest living species.
Myths, legends and incidents with sperm whales
In March 2007, a Japanese fisherman drowned after his boat was capsized by a frightened sperm whale he was trying to rescue. The whale was wandering in the relatively shallow waters in a Shikoku Bay.
Perhaps the most famous news about a sperm whale is to go back to 1970, when a decaying animal weighing 7.25 tons and 13.7 m in length came ashore in Oregon. For some time it was a curiosity for local residents. As the beach is public transit, it was the responsibility of the Oregon Department of Transportation members to take care of this.
They filled the animal with half a ton of dynamite. On Friday, November 12, dynamite was detonated, but the explosion did not make its way to the Pacific, as had been predicted. No one was injured, but a car was destroyed by the rain of grease.
The spectators were covered with stinking bits of dead sperm whale. In January 2004, a far more glaring event took place in the spotlight of the global media. A dead sperm whale, 17 m long and 50 tons heavy, ran aground on the beach in Tainan City, Taiwan.
While being transported to the city's university, the pressure of decomposition gases inside the body caused an explosion. No one was injured, but blood and guts spilled over some cars and engulfed pedestrians. In July 2003, a huge indistinct mass of white meat was found on a beach off the coast of southern Chile.
The 12-meter long mass of gelatinous tissue suggested that an unknown giant octopus had been discovered. Researchers at the Natural History Museum of Santiago instead concluded that the mass was actually the inside of a sperm whale, a conclusion deduced from the observation of the dermal glands.
When a sperm whale dies, its internal organs decompose, until the animal becomes little more than a semiliquid mass trapped under the skin. The skin can eventually tear, causing the internal mass to come out and possibly stranding.
Dead sperm whales often float towards the coast. In addition to the decomposed tissues noted above, beach managers fear that sharks, especially the great white shark, may be attracted to the beach by rotting flesh and may cause a potential danger to swimmers.
For this reason, dead sperm whales are often towed offshore before they hit the beach. This happened twice in May 2004, once off the coast of Oahu, Hawaii, where a dead sperm whale was towed out to sea for 35 miles, but returned to the coast two days later.