Published on April 16th, 2013 | by Yellow Magpie2
Sperm Whale: The Record-Holding Toothed Whale
Sperm Whale Mother And Calf Photo By Gariel Barathieu
Sperm whales are enormously massive animals. They were the subject of such fear and dread in the novel Moby Dick that the Sperm Whale has taken on mythical significance in the human consciousness. But there is far more to them that just an angry mammal thirsty for revenge.
Sperm Whales hold many records – from having the longest digestive system to being the deepest mammalian divers. Of all the animals it also emits the farthest reaching sounds. The largest toothed predator that roams the Earth’s waters – they truly are behemoths of our oceans.
An Impressive Specimen
The degree of difference between the Sperm whale sexes when it comes to size is the greatest among cetaceans. Adult males can be up to three times heavier than females and half as long.
The whale’s profile is also very distinctive. The Sperm whale has no dorsal fin instead it posses a series of ridges on its back and its skin has a wrinkly or wizened appearance. Its tail or fluke is one of the largest found in whales.
Ultimately, what is most unique about the Sperm whale when it comes to bodily form is its mouth. Its long, very narrow lower-jaw is highly unusual and bares the biggest teeth of all the toothed whales.
The Biggest Brains On Earth
The Sperm whale is the owner of the largest brain in the entire animal kingdom. Weighing almost eight kilograms (17 lbs) it is nearly five times heavier than the average human brain.
At eight litres it has more than six and a half times the volume of our own typical brain which are roughly 1,100 to 1,300 cc. Although given its vast size such a huge brain is not unexpected.
The Sperm Misnomer
The Sperm Whale is actually named after the oil contained in its spermaceti organ. The oil is a very good conductor of sound travelling at a speed of over 2,600 metres per second. For comparative purposes sound travels at over 1,500 metres per second in seawater which is over four times faster than when it moves through the air.
Such characteristics make the spermaceti organ excellent for echolocation. The whale generates sound by creating clicking noises with its phonic lips. This sound is then transmitted along its right nasal passageway where it is amplified by the spermaceti organ. The sound is then reflected by the frontal sac which shapes the sound wave into a beam. It is then boosted again by the junk which consists of spermaceti oil separated by vertical layers of cartilage.
The Most Powerful Echolocator
Sperm whales are responsible for producing the most powerful sounds in the animal world. These noises form clicks ranging in intensity from 180 to 230 decibels at source level.
Hunting clicks have both shorter durations and shorter intervals between clicks while the whales are chasing prey than when they are socially communicating with one another. Whilst hunting the sounds are also more focused in direction. Sperm whale clicks become almost continuous when they zero-in on their prey.
Communication between males can be heard by other Sperm whales at distances of up to 60 km (37 miles).
Diet And Feeding Habits
The Sperm whale’s diet is thought to consist mostly of Cephalopoda namely the Giant and Colossal squids. To hunt these types of prey requires extraordinary diving abilities.
Sperm whales routinely dive up to 1,000 metres (3,300 feet). Nevertheless, dives as far down as two and a half kilometres (one-and-a-half miles) are generally accepted as being close to the limit of the Sperm whale’s deep-diving abilities.
Their dives can last from anywhere up to an hour and half. Sperm whales typically take ten to 15 minutes recovering at the surface before they undertake the next deep plunge.
It is also worth noting that beyond 200 metres you enter the twilight zone where visible light becomes greatly diminished and is available only to the most sensitive of eyes. At roughly 1,000 metres it is almost completely dark. If a human being were able to dive to these depths without being crushed to death they would find it very difficult to tell which direction the surface resides.
To accomplish these physical diving feats Sperm whales are supremely adapted. Their blood has very high haematocrit levels. These elevated amounts of red blood cells in comparison to a human being mean that their blood has a much higher oxygen-carrying capacity.
To add to their oxygen content Sperm whales have large amounts of myoglobin in their muscles. They also have the ability to control where their blood delivers oxygen cutting the supply off to non-vital organs and sending it to where it is critically needed.
Their massive lungs hold up to 5,000 litres of air and the ribcage that surrounds them is very flexible aiding their collapse under the crushing pressure of the water. This lung collapse proves very necessary to Sperm whale survival as it prevents dangerous air embolisms from damaging the cardiovascular system – what we call decompression sickness.
It is thought that the spermaceti organ, more specifically the spermaceti oils, may play a big role in adjusting buoyancy. During dives cold water is thought to enter the spermaceti organ constricting blood vessels and reducing the temperature of the oil. This loss of heat is believed to solidify the waxy oil. The now solid spermaceti oil experience a reduction in volume which increases the whale’s density helping it to sink.
During the chase the reverse occurs and the solid oils are heated increasing the Sperm whale’s buoyancy. It must be stated that some researchers are sceptical about the presence of structures to facilitate this method of heat exchange.
Despite all these adaptations, skeletons of adult Sperm whales have shown the tell-tale signs of decompression sickness – emphasising the dangerous nature of their deep-diving feeding habits.
Sperm Whales are social creatures. Females and juvenile males live in tight-knit pods numbering up to twenty. They devote a substantial period of their day to social activities when they are not feeding.
Males leave the group while they are quite young. On occasion young bulls may form pods with other male Sperm whales. Nonetheless, as they get older they tend to live a solitary existence.
While fully-grown males have no non-human predators juveniles and even sometimes adult females can come under attack from pods of Orca dolphins. Sperm whale pods will often organise themselves into a defensive formation to protect the more vulnerable members from attack.
Sperm Whale: Sinker Of Ships
The mythical status of the Sperm Whale has definitely been strongly shaped by Hermann Melville’s Moby Dick. Nevertheless, the depiction does have some basis in reality. Sperm whales have been responsible for the sinking of several whaling ships.
Apart from the myriad destruction of small whaling boats two of the most famous incidents include the of the sinking of the Essex and the Ann Alexander. Both ships were easily five times heavier than the attacking Sperm whale.
The Legacy Of Whaling
The spermaceti organ, which could provide almost 2,000 litres of spermaceti oil, made the Sperm whale a highly sought-after commodity in the 19th and 20th centuries. During the two-hundred-year span an estimated one million whales were slaughtered.
The Sperm whales were finally given worldwide protective status in 1985. It is believed that today’s population of whales is one-third of what existed before commercial whaling.
Scientists have calculated that the reduced population has contributed to two million tonnes of carbon being released into the Earth’s atmosphere per annum. This figure is the equivalent of ten million tonnes of carbon dioxide roughly the same output as Luxembourg’s CO2 emissions – an EU country with a population of over half a million people.
- Sperm Whales can grow to be over 20 metres in length (65 feet).
- They can weigh as much as 57,000 kilograms or 57 gigagrams.
- Sperm Whales are found in most marine waters that are deep enough to support their hunting patterns.
- They can live to be over 70 years old.
Visit Wikipedia for more information on the magnificent Sperm Whale.
Check out Yellow Magpie’s The Whales: Kings Of The Cetaceans, Fin Whale: The Giant Speedster Of The Oceans and Dolphin: Our Love Affair With Our Favourite Cetacean for further insight into Whales and their cetacean cousins.
Among Giants: A Life With Whales is the fascinating story of underwater photographer, Charles ‘Flip’ Nicklin. Full of stunning pictures and insightful commentary about the whales this book is stunning.
You can obtain Among Giants: A Life with Whales here from Amazon.
For people living in Ireland or the United Kingdom, you can access: Among Giants: A Life with Whales from here.
For Canada: Among Giants: A Life with Whales.
For Germany: Among Giants: A Life with Whales.
For France: Among Giants: A Life with Whales.