Dwarf Sperm Whales: Are they Endangered?  

The dwarf sperm whale, as the name suggests, is the smallest whale species from the Physeteridae family, primarily found in the tropical oceans.

Dwarf sperm whales, like others of their kind, also come under the Marine Mammal Protection Act in the US, for their number is precarious, and their appearance is rarely spotted in the wild. 

• Status: Data Deficient
• Also Known As: Kogia Sima, Kogia simus, sperm whale
• Estimated Number Left: Anywhere between 7,000-15,000

They are often confused with pygmy sperm whales for the resemblance they bear, only distinguished by the location of their dorsal fin. However, they have a dolphin-like stature and some similarities with porpoises.

The spermaceti organ is unique to all sperm whales, and dwarf whales are no different. Various descriptions of spermaceti are found from early times, and in literary pieces like Moby Dick.

Dwarf Sperm Whale Description

Dwarf sperm whales are rarer mammals with gray-colored bodies of smaller sizes compared to Sperm Whales, usually between 8-13 feet. Some of them are even smaller than dolphins. 

They have smaller jaws but a sturdy, strong, and asymmetrical body. Unlike the other species, dwarf sperm whales remain in relatively smaller pods, and even they are spotted solo sometimes. 

Human encounters with dwarf whales are rare, as they are typically cautious. Their blow from the sea isn’t very conspicuous either.

Usually, they are not aggressive for no reason. But for self-defense, they discharge a considerable amount of red-brown fluid. Their lifespan is no more than 22 years, the lowest among whales. 

See Related: Blue Whale: Why Is It Endangered?

Anatomy and Appearance of the Dwarf Sperm Whale

Dwarf sperm whales are among the smallest whales on the planet. They have a compact and robust body with a flat back and head. The underslung jaw and the square head give them a distinctive look. 

And they have pointed snouts, more pointed than pygmy sperm whales. Their appearance is somewhat like sharks and dolphins rather than baleen whales. The dorsal fin is situated on the back but much closer to the head than pygmy whales. 

The dorsal fin is the only noticeable marker that can help to differentiate between their sister species the Pygmy Sperm Whale.

The standard size of this marine mammal is between 2 to 2.7 m. Moreover, their weight ranges from 300 pounds to 600 pounds. The brain can weigh up to 1.1 pounds – smaller than their closest relative – those pygmy sperm whales. 

They are adept predators, they have sharp teeth both in the upper and lower jaws. In addition, there is usually a false gill slate between their protruding eyes and flippers because they look similar to the gilt of some fishes. 

The flippers of dwarf sperm whales are much shorter in appearance and much forward than others. Down their throats, they have two or more grooves. 

Location

Dwarf sperm whales can be seen in the waters of the Pacific, Mexican Gulf, Bahamas, North Atlantic, Southern Brazil, and a few other places. 

Dwarf sperm whales are among the few toothed whales found near the Hawaii Islands. Their presence has been reported in East Pacific, the Japanese coast, British Columbia, and the Mediterranean sea. Moreover, stranded dwarf sperm whales are sometimes seen in the Indian Ocean.

These marine mammals usually dive around 250m deep off the sea coast, but they can reach up to 1,500m deep in search of prey.

Dwarf Sperm Whale Habitat

Dwarf sperm whales mainly live in tropical oceans, and in warmer waters. The habitat of dwarf whales stretches across the world’s oceans – from the Atlantic to the Pacific oceans.

They avoid the icy-cold areas. They prefer calm areas and sun rays to the colder ones. They tend not to approach human vessels because these vehicles’ sounds cause communication problems between whales.

Sometimes, they have been found in coastal areas, basking in the epipelagic zone. The pollution of waters is constantly constraining their habitats nowadays.

See Related: Fun, Interesting Facts About Whales

Dwarf Sperm Whale Diet and Nutrition

What does the Dwarf Sperm Whale eat? Turns out, quite a lot!

A sperm whale’s food habit is similar to pygmy whales. After childbirth, they are lactated like other mammals. A single calf is lactated for more or less 18 to 20 months. But as they reach the age of 6 months, they begin to take solid foods like their parents.

The dwarf sperm whale diet consists of giant squid, fishes, crustaceans, and even cephalopods. They use the suction feeding technique to eat this Dwarf sperm whale food.

When a sperm whale eats, it keeps the prey in the smaller jaw while evacuating flowing water from its mouth. Sometimes, they mistake the plastic and marine debris for fish. Eating this trash can cause eventual death to the whale.

A single meal can consist of 2-4% of their body weight. They take the bulk of their freshwater from their prey.

Hunting

Dwarf sperm whales are good hunters with their ingenious echolocation system. They use the system to navigate through the world’s oceans and find prey. All whales have “melons” in their foreheads that produce a particular sound.

This sound is mainly produced while they search for food. They make a noise, then when the sound wave reflects and returns to them after bouncing off prey, they locate that prey based on the direction and amount of time elapsed from the bounceback.

They prefer munching on open ocean fish, squid, and crustaceans. They often prey on smaller-sized animals. 

They can dive deep down into the ocean in search of prey. Their deep dives can reach more than 1,500m.

See Related: Habitat Loss Solutions You Need to Know

Dwarf Sperm Whale Mating Habits

There is so little information about the mating habits of this cetacean species. Sexual habits are thought to be like other whales of its kind. 

What is known is that dwarf sperm whales usually copulate during the autumn or winter season. Their pregnancy period may be longer than humans-from 9 to 12 months. During summer, they give birth to one calf. Their childbirth process is similar to other marine mammals.

Lactation continues for several months, and they begin taking normal food after six months. They become sexually mature at the age of 2.5 to 5 years old.

Life Cycle

There is deficient data on the life cycle of dwarf sperm whales as they are rare. Usually, their lifespan is no more than 22 years, quite a lot lower than other sperm whales. The entanglement in the fishing nets and premature death can contribute to a poor lifespan. 

The gestation of this whale usually takes from 9 months to 12 months. At the time of birth, a single calf is around 3 feet long and can weigh around 30lbs. The lactating period is around 18 months. 

Sexual maturity for male whales comes at the age of 2 or 3, and for females, it comes at the age of 5. They normally grow to around 7 feet at length in this puberty period. 

Physical maturity comes at a later period of life. For females, 13 years is the estimated time, and for mature males, the age is 15. It’s worth noting some anomalies can be found, and some whales can mature faster or slower than others.

Dwarf Sperm Whale Populations

There is no exact estimation for these marine mammals. As they look similar to pygmy whales and inhabit a lot of the same ecosystems as their pygmy cousins, it is very confusing to count and confirm anything close to a precise number.

One thing’s for sure is that from the beginning of the whaling era, their numbers have decreased exponentially. So whatever of them are left are very few in numbers compared to what they once were.

However, there are some estimations of the sperm whale population. According to Wikipedia, 15,000 whales are left between the pygmy and dwarf species. But some estimates have concluded their number as 19,000 in the Hawaii region alone.

Some of the estimated total numbers exceed 20,000. One thing is clear; their number is pretty precarious, especially for an animal with such a low birthrate, long gestational period, and relatively short lifespan.

The number can be debatable yet seems fair enough. This low number has made them a potentially endangered species, although few bodies recognize this.

That said, the International Union for Conservation of Nature (IUCN) has declared them as data deficient species and the International Whaling Commission lists them as a protected species.

See Related: What Is The Main Effect of Overpopulation on Animals?

Role in the Ecosystem

The dear little Kogia sima has an important part to play in the ecosystem. Dwarf sperm whales have a mutual interest in spearfish remoras. That’s why spearfish are often found on the fins of sperm whales.

What is more interesting is the commensal relationship. Dwarf sperm whales host a good number of intestinal parasites. These parasites range from nematodes and trematodes to cestodes.

Dwarf sperm whale populations help to accommodate these endoparasites…but they also help feed less friendly sea creatures. Some larger whales and some sharks often prey on dwarf sperm whales.

Thus, the presence of dwarf whales has consequential effects on the whole ecosystem.

Relationship with Humans

As the encounter between these two mammals is rare, the relationship isn’t terribly complicated. The size of dwarf sperm whales makes them not a lucrative target for fishers or whalers. That’s why commercial whaling for dwarf sperm whales is not so popular.

However, they are sometimes hunted down for preparing baits in the Lankan, Indonesian region. And entanglement in fishing gear as bycatches is a more common scenario for these poor wee whales versus actual whaling.

As a whole, people do not really target these whales anymore. Even if and when people target dwarf sperm whales, these cases are rare.

Dwarf Sperm Whale Attacks On Humans

Dwarf sperm whales mainly feed on giant squid and fish. They do not like humans as food. Even theoretically, they can’t swallow a person whole, and no such incidents have ever been recorded. 

Attacks on humans by dwarf sperm whales are only a few in number. They sometimes mistakenly attack humans, thinking they are fish or squid. In these cases, the whales release their unlucky victims after realizing the mistake. 

These cases are so rare that dwarf sperm whales are essentially considered placid and non-fatal for humans.

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Dwarf Sperm Whale vs Other Sperm Whale Species

Dwarf sperm whales are closely related to two other whale species in their family, sperm whales, and pygmy sperm whales. While the latter has significant similarities, the previous species have conspicuous differences.

Sperm whales (physeter macrocephalus) can grow up to 68 feet, and their weight can reach a whopping 80 tonnes. Unlike dwarf whales, sperm whales’ heads are the largest ones, and the spermaceti organ (which sits on top of the “melon”) can hold a good chunk of invaluable liquids.

That’s why sperm whale hunting was a lucrative venture for early whalers of the 19th Century.

So the decreased is the sperm whale population the International Whaling Commission lists sperm whales as a protected species and the International Union for Conservation of Nature has named sperm whales a vulnerable species.

Pygmy sperm whales, on the contrary, have similar physical stature to dwarf sperm whales but are a bit bigger in size. Therefore, it is difficult to differentiate between them unless one looks into the position of their dorsal fins. The dorsal fins of dwarf sperm whales are taller and closer to its head.

Both of these little whales also have spermaceti organs containing spermaceti oil. The pygmy whales like tropical waters, but their presence has also been spotted in the cooler parts of the southern hemisphere.

Both two species prefer solitary lives, though they are often found in small pods. All sperm whales come under the Marine Mammal Protection Act.

Dwarf Sperm Whales vs Blue Whales

So how does one of the smallest species of whales compare against the biggest?

Antarctic Blue whales are the largest mammals on earth. Their average length is a whopping 25m. A large blue whale can reach even 28m lengths.

On the contrary, a dwarf sperm whale’s length is no longer than 3m – and a dwarf sperm whale of that size is practically a freak of nature. So basically, these two species have a massive difference in their size despite being from the same Physeteridae family.

See Related: Whale Shark: Species Overview and Conservation Efforts

Dwarf Sperm Whale Interesting Facts

There are some really interesting facts about dwarf sperm whales. Here’s the list of them.

• Dwarf whales are the smallest whale species. Even most dolphins are bigger than dwarf species!
• The upper jaw of dwarf sperm whales has only six teeth, while the lower jaw can have anywhere between 16-24 teeth.
• Historically, pygmy and dwarf whales were thought to be the same species. Then, in 1966, scientists recognized differences and confirmed them to be different from each other.
• The “squid tactic” is something very interesting about dwarf whales. When an enemy attacks stranded dwarf sperm whales, they eject around 12 liters of thick cloudy liquid. This liquid confuses the enemy, blocking their vision and allowing the whale to make its escape.
• Large toothy whales (like Orcas) love to prey on their own kind – especially dwarf sperm whales.
• What’s more, they are often preyed on by sharks.
• It is reported that whales usually sleep just below the surface. It gives them the ability to breathe regularly rather than taking and holding huge breaths.

Dwarf Sperm Whale Conservation Status

As there is no officially established number so far, dwarf sperm whale conservation status is labeled as data deficient by IUCN red list. That means the data isn’t adequate to decide on a category for them. They are also considered “least concern” animals by the same organization.

But their estimated lower number has given them the protection of the Marine Mammal Protection Act. And often, all sperm whales are considered an endangered species.

After the passing of the whaling era, their numbers are recovering. Yet, there are some significant threats to their existence, and their former number is yet to recover.

Threats to Dwarf Sperm Whales

Commercial whaling isn’t a real threat to dwarf sperm whales now, but some other dangers are lurking for dwarf sperm whales. Most of them are man-made, but some are natural. So let’s find out the threat to dwarf whales.

Pollution

Pollution is a real threat to the existence of sperm whales and to the existence of natural order. Polluted water is not suitable for keeping a normal lifespan for ocean creatures. In addition, the marine debris thrown by humans can cause injury and even death to sperm whales.

Plastic wastage is also causing enough problems for the oceanic realms. Sometimes the marine debris is mistaken as food, and sperm whales swallow it. But as the flotsam and jetsom are not suitable for digestion, the little marine mammals suffer considerable pain, injury, and eventually death.

Oil spills also make the ocean unworthy of living for marine animals. So yeah, pollution is a real problem for the surviving dwarf whales.

Entanglement in fishing gear

Fishing gear has posed a grave threat to the existence of sperm whales. The tropical waters are a favored fishing ground for sourcing various high-value fishes. But dwarf sperm whales may get entangled in the fishing gear and dragged for a long time, leading to exhaustion, injury suffocation, and death.

Even surviving a netting encounter can result in serious injury that could impact reproduction.

Disease

Parasite infestation is a common problem in dwarf sperm whales. Excessive parasites lead to intestinal problems.

Moreover, stranded whales often face heart and immune system failure. These diseases are reducing their numbers with early deaths.

Predators

Another natural threat is the food habits of other whale species like killer whales. Large sharks also prey on dwarf sperm whales. As these large predators prey on this vulnerable species their numbers decrease.

Marine Vessels

Oceans are home to millions of marine species. But humans have taken over the waters for several purposes. The number of sea vessels has only ever increased since the beginning of human civilization.

Sea vessels often strike the dwarf whales unintentionally. Dwarf sperm whales love to bask just below the surface in the epipelagic zones. Unfortunately, as a result of these habits, they are sometimes hit by ships and boats. This causes injury and frequently an untimely death.

Climate Change

Climate change will continue to have a wide range of impacts on the ocean. Dwarf sperm whales are also affected by it. As oceanic temperatures change, they will likely lose more of their habitats, and it will threaten their food availability.

Already overfishing has caused considerable damage to their food habits. Now they might lose their home as well.

Ocean Noise

One of the main threats for these toothed whale species is the noise pollution caused by humans. The sound echolocation technique is the mean of whales’ communication and finding food.

When these sounds are interrupted, they confuse their prey with boats, have their navigator lines muddled, and even have their migratory behavior interfered with.

Scientists have found a considerable change in whales’ behavior when they are affected by ocean noise. As a result, they are often displaced, stranded from the pods, lose their migratory line and even end up in inland rivers.

Some research shows that noise pollution causes stress and hormonal imbalance in physeter macrocephalus.

See Related: Causes of Extinction You Should Know About

Dwarf Sperm Whale Conservation Efforts

The NOAA has taken several steps to conserve this little marine mammal. They have proposed some steps to protect endangered species. These proposals are as follows:

• Reduction of fishing vessels in dwarf sperm whale habitat areas
• Decreasing the vessel noise and maintaining a soundless ocean (as best as possible)
• Keeping the water clean and cleaning up pollution
• Making critical habitats for dwarf sperm whales
• Ensuring treatment for the bycatch whales that survive being netted and giving them safe passage
• Banning dwarf sperm whale hunting efforts outright by all government and wildlife organizations

Organizations that help Dwarf Sperm Whales

Some organizations are trying to preserve this potentially endangered species from inevitable extinction. For example, the National Oceanic and Atmospheric Administration (NOAA) are trying to save these mini marine mammals.

Is the dwarf sperm whale endangered or not? Are dolphins endangered as well? Well, NOAA data helps to decide the answer. And they propose possible solutions.

Some organizations are trying to remove marine debris to make the ocean clean and liveable for all marine mammals. Sperm whale projects are also going on to reinvigorate their numbers. Among these organizations, OceanCare, and the International Fund for Animal Welfare (IFAW) are among those mentionable.

World Wildlife Fund

World Wildlife Fund is doing an excellent job of preserving the marine environment. They have been running the whale project for the last few decades.

In 1984, it was by their efforts the world banned commercial whaling. They have a global outreach and influence over other environmental organizations to achieve their demands.

They also have projects for critical habitats to make a safe zone for the whales. Presently they have three distinctive aims to preserve sperm whales of all species and dolphins too. These are:

1. To secure a safe passage for whales caught as bycatch in fishing nets
2. To reduce the excessive noise pollution in oceans
3. To improve the habitat for cetacean species

These efforts are not enough, though. Therefore, WWF also includes awareness-spreading plans and campaigns.

How you can help protect dwarf sperm whales

Protecting the dwarf sperm whales is a collective responsibility of humanity. Though it is the duty of states and organizations, you can help save them too.

But how?

First, you have to reduce plastic usage, especially plastic bottles. A good way is to recycle and reuse plastic. Moreover, reusable bags are always better than plastic bags. The less plastic we use, the less makes its way into our oceans.

Secondly, you can volunteer to clean coastal waters and raise awareness against hunting attempts of dwarf whales. Charity starts at home, even in the case of saving dwarf sperm whales – cleaning must start with your own community first.

Thirdly, try to switch over to products with non-toxic chemicals. Everything from cleaning products to deodorants.

Final Thoughts

The dwarf sperm whale is an important part of our ecosystem. Therefore, if we want to preserve the balance of the marine environment, it would be a vital step to ensure the conservation of all sperm whales.

Firstly, we should make some critical habitats. Secondly, the bycatch whales should get the best attention to come back to the ocean waters. Finally, there should be strict laws implemented by the authority against any attempted whale hunting.

There should be a certain limitation of noise produced by the sea vessels. Water pollution should be dealt with at any cost, not just for whales but for human beings as well.

If we can ensure the ocean’s safety, we shall also bring safety for us.

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