The Reason Why the Ocean Needs No Hearing Aid

Everything about the Elusive Sperm Whale

The sperm whale can be found worldwide from tropical to polar latitudes, representing one of the widest distributions of all marine mammals with their natural habitat spanning anywhere from the Arctic to the Antarctic. Although all sperm whales typically stay away from the extreme cold near the poles, females and their calves often prefer tropical and temperate waters while their male counterparts opt to roam temperate and polar waters on their own.

Sperm whales are known to be extreme deep divers that reside in open oceans as active apex predators on the marine food pyramid. To hunt effectively, these creatures are equipped with conical teeth in order to be able to “ensnare” their preferred prey—whether that happens to be deep-sea cephalopods (particularly squids, including giant squid and octopuses) or various fish, sharks or rays. Males have about 40 to 50 teeth, located only in their narrow lower jaw, while females have even fewer. Like many other active predators, sperm whales have large brains. To be more specific, they possess the largest brains of any animal on Earth.

To navigate and hunt in their pitch-black environment, sperm whales have the most powerful sonar of any animal, allowing them to catch prey in the deep dark sea. This sonar allows them to dive to depths up to 3280 feet for two hours, significantly increasing their likelihood of catching a nutritious meal. They favor these deep waters due to the fact that strong currents flow in opposite directions which brings along concentrated nutrients to the area, attracting a large number of creatures for the sperm whales to consume. Because of this distinct preference, sperm whales typically descend thousands of feet within minutes and are rarely seen along the coast unless a deep trench or canyon approaches the shore.

The Sperm Whale’s Unique Dresscode 

This deep-diving lifestyle is reflected in their unique anatomy. Sperm whales have an iconic, blocky rectangular head due to their large brains and a specialized sonar organ known as a melon. In addition, they have outwardly gray bodies with occasional white patches on the belly in order to blend into their desired environment.

Visually, sperm whales have a hump rather than a traditional dorsal fin, as their actual dorsal fin is very small, low, thick and rounded. Furthermore, they have triangular-shaped flukes, or tails. Just behind their large head, which totals one-third of their total body length, their skin is wrinkled to increase surface area, leading to greater heat loss.

Sperm whales also possess a single, S-shaped blowhole located on the left side of the top of their head. They are the only known living cetacean that has a single blowhole asymmetrically situated on the left side of the crown of the head, and this unique feature produces a highly distinctive, angled spout.

A Sperm Whale’s Entire Life

Sperm whales are thought to reach sexual maturity within their teenage years, around nine years of age. Females continue to have one young (measuring around 13 feet and weighing one ton) every three to five years until their forties. On the other hand, males experience puberty between the ages of 10 and 20 and do not actually breed until their late twenties. Once fully grown, the sperm whale's natural lifespan can continue well into their seventies.

Within that lifespan, calves will be nursed for their first two years but may continue nursing with their mother irregularly for up to eight years. Because baby sperm whales cannot undergo long expeditions into the deep dark sea like their mothers, female sperm whales form tight-knit bonds. This social structure allows one mother to go in search of food while the other mothers stay behind to protect the young.

In terms of sheer scale, sperm whales can grow up to 52 feet and 90,000 pounds, making them the largest toothed whales, with males growing significantly bigger than females. Female and young male sperm whales are highly social and are sometimes seen in pods, or groups, of up to 50 whales. The females form matriarchal, or female-led, pods and create social groups around these bonds. Interestingly, pods of sperm whales even sleep vertically in the water column. The young males, however, will often leave these groups between the ages of 4 and 21 to form bachelor herds until they are able to compete in mating at about 20 years old. Aside from the breeding season, adult males lead a solitary life. 

Diving Down

When diving, sperm whales can go so deep that their lungs collapse, yet they consistently stay underwater for around two hours. 

The deep ocean features pressures 120 times greater than the surface, which would kill most creatures. Yet, this is where sperm whales fight their prey, often battling giant squids and returning to the surface with circular battle scars. To prepare for this, they fill their lungs with one final breath and descend, spending around 90 percent of their time within the deep ocean.

To aid their natural buoyancy, sperm whales evolved a substance known as the spermaceti organ, an oil-filled cavity from which they get their name. The oil is usually a warm liquid, but when the whale dives, cold water solidifies it, acting like a diving weight to pull them down. As they descend and the pressure becomes intense, the whale's lungs are forced to collapse. The rib cage hinges closed around the collapsing lung, squeezing most of the air into the trachea so there is less gas exchange in the lungs, which protects the whale from dangerous nitrogen buildup.

To compensate for the lack of oxygen in their collapsed lungs, sperm whales have a much higher concentration of red blood cells containing myoglobin and hemoglobin than land mammals, which serves as a built-in oxygen tank. They also have clumps of blood vessels near the brain called retia mirabilia, essentially vascular nets that regulate blood pressure and keep the brain well-supplied with oxygen. During the dive, the sperm whale heart rate slows in a process known as bradycardia, slowing down all other physiological processes so the body does not consume too much oxygen and limiting gas transport around the body. Furthermore, their trachea has extra cartilage so that nitrogen is safely stored rather than dissolved in tissues, though they can still suffer from the bends if they are forced to ascend too quickly. What might force them to ascend so rapidly, other than ocean noise, remains a mystery.

One of the Ocean’s Greatest Mysteries 

Another major mystery is how sperm whales actually catches their prey. Their mouths are not well-suited to latching onto things because their teeth are located solely on their narrow lower jaw, and their teeth are also not effective for chomping. There’re many theories regarding their hunting tactics. One theory states that they dive down and hang out in one area for a while as  "sit and wait" predators, opening their mouths so that glowing bacteria on their teeth can lure prey in. Another theory suggests they may rake the seafloor with their teeth like a plow to disturb organisms in the sediment, causing creatures like crabs to jump up and get sucked into their mouths.

The Sperm Whale’s Characteristics 

Their gray matter weighs 7 to 9 kilograms, which is six times larger than a human's. In cetaceans, a big brain is closely linked to social behavior. For instance, many male sperm whales spend a lot of time with male friends, migrating and feeding together. The species is also tied together by robust vocalizations produced by their massive noses. Indeed, one-third of their body length is their nose, making them the largest sound producers in the animal kingdom.

To make these sounds, the spermaceti oil takes vibrations produced in the front of the sperm whale's boxy head. Air is brought to the front and passes through a pair of phonic lips inside the nose that click. As they click, they vibrate the lip tissue. This lip is attached to the spermaceti organ, which sends a vibrational wave propagating through the organ until it reaches the back of the head, where the click is reflected through an air sac in front of the skull. The sound is then modified into a sharp beam or a quiet rumble by a structure called the junk (or melon).

Sperm whales can click at incredibly high decibels. For reference, human eardrums rupture at 150 decibels. Big males produce a "clang," which is a very loud, intense sound used for mating. They have many different patterns of clicks.To communicate personally, sperm whales produce a series of clicks called codas. Codas sound much like Morse code, and each regional clan has its own specific codas that hold the clan together. Females tend to use codas more than males do, communicating to protect their young and coordinate with one another. These vocalizations represent their own distinct culture, similar to orcas, with different sperm whales exhibiting different behaviors. The sperm whale language is just as complex as ours. In fact, calves can take up to two years to make up codas, babbling like human infants until they learn the proper sounds. Because codas differ slightly among individuals, some scientists believe they may even have unique names, which they use alongside shared strategies to avoid danger and death. 

What is Happening and What Can We Do

Wrongful human contributions to the sperm whale and their natural habitat such as whaling, the release of chemicals and metals all the way into Antarctica, ship strikes and the wrongful disposal of fishing gear into their home have led to this species being marked as either vulnerable or endangered depending on the source. In order to protect this sacred creature, do not be afraid to find local organizations and volunteer in a multitude of ways, whether that is monetarily or by offering your time and effort for protesting their dues or even cleaning up trash within your communities. These creatures did not ask for our negligence, nor do they deserve it. We have an obligation to protect them from the certain doom we have wrongfully placed upon them and educating ourselves on the matter is a necessary first step.