The pygmy sperm whale is a toothed whale that belongs to the cetacean species which includes all species of whale, dolphin and porpoise.
This whale is 1 of 3 species of sperm whale; the other two are the sperm whale and the dwarf sperm whale.
The pygmy sperm whales is a very rarely sighted marine mammal due to its small size, oceanic habitat and inactive nature.
In fact much of what we know about this species comes from examining lost or stranded whales.
Physical Characteristics and Appearance
Visually the pygmy sperm whale closely resembles its dwarf sperm whale cousin.
This whale is a bluish gray color with a lighter pinkish colored under body.
Behind each eye these marine mammals have a light, curved line that is known as a “false gill” as it can be confused for a real gill when viewed from a distance.
in terms of size the pygmy sperm whale is slightly larger than its smaller cousin (the dwarf sperm whale) measuring between 9 1/2 – 11 1/2 ft. long and typically weighing between 600 – 1,000 pounds.
The dorsal fin is also smaller in size when compared to the dwarf sperm whale.
To assist with swimming these whales have a pair of flippers to help them turn and steer in the water and rear flukes which they move up and down to propel themselves forward.
In terms of dentition these whales may have anywhere from 10 – 16 teeth in their lower jaw, but lack having any in their upper jaw.
Whether or not their teeth are necessary for hunting prey is uncertain as their larger sperm whale relative is known to successfully capture prey without teeth and even with a deformed jaw.
When threatened these marine mammals can release a dark ink to blind their predator while they escape unharmed.
Once they eject this ink they then use their flippers and flukes to disperse the ink in the water in order to create a large blinding cloud.
Diet and Hunting Methods
The diet of the pygmy sperm whale consists mostly of crab, shrimp, fish, octopus and squid.
When searching for food it is believed these whales can reach depths of up to 1,000 ft.
As with other toothed whales these marine mammals locate their food and navigate the ocean using echolocation.
Echolocation also provides the pygmy sperm whale with an early warning to incoming predators.
Unfortunately the methods they use to capture their food isn’t well known.
Habitat and Migration
These whales are found swimming in the Atlantic, Pacific and Indian oceans and prefer to live in tropical and subtropical climates, however due the difficulty of spotting and tracking these whales it has been difficult to track their migration patterns (if they have any).
Social Structure and Communication
The pygmy sperm whale is largely a solitary mammal that prefers traveling alone or in small groups although they may be found traveling in small pods of up to 8 other whales during certain times.
Rising slowly and barely breaking the surface of the water they are a very inactive species and rarely bring attention to themselves.
While the reason for this isn’t fully known it is possible that their quiet, inactive nature helps minimize the likelihood of them being spotted and attacked by potential predators.
When in the presence of ships and/or boats they are more likely to keep their distance rather than approach.
Most of the time they can be found swimming very slowly or logging around (floating motionless) at the surface of the water.
Unfortunately not much else is known about how these whales socialize.
As with other toothed whales communication involves making high-pitched sounds that may be used to help them locate other whales, state their interests and assist with echolocation.
Mating, Reproduction and Lifespan
The average gestation period (pregnancy period) for these whales is 9 -11 months.
Newborn whales are usually born between 3 1/2 – 4 feet and may weigh between 100 – 150 pounds.
Once born the baby whale is nursed by its mother and fed milk for about 1 year or until it is able to hunt for food on its own.
Once sexually mature the pygmy sperm whale can begin mating and reproducing offspring of its own.
Unfortunately the age they reach sexual maturity is unknown.
When it comes to lifespan these whales are believed to live only until their mid twenties.
Predators
While little is known regarding natural predators it is likely that these whales may be hunted by killer whales and possibly sharks as both of these animals are known to hunt other species of cetacea.
The small size and solitary behavior of the pygmy sperm whale makes them an ideal target for larger predators looking for an easy, defenseless meal.
In order to protect themselves these marine mammals lead fairly inactive lives in order to make themselves hard to locate or spot.
When a potential predator is nearby the pygmy sperm whale can use echolocation to identify the threat and will release a dark ink cloud to block the view of its predator so that it can escape.
Threats
Due to their small size and motionless nature these whales can be hard to spot and may occasionally be stuck by large ships and boats.
They may also be affected by fishing nets, man-made ambient sounds such as sonar and boat engines and occasional hunting.
Pygmy sperm whales rely on echolocation in order to hunt for food and navigate the ocean and may have difficulty distinguishing sounds due to human created sounds becoming more and more common in their aquatic habitat.
Some sounds may even cause permanent damage to the whales hearing.
Pollution has also been found to play a role in endangering the health of these whales.
In some cases these have been found with plastics and other garbage in their intestines.
Chemical pollution from oil spills and other types of chemicals can lead to direct or indirect poisoning either by affecting the whale or its food supply.
In more recent years heavily commercialized areas have also caused some whales and dolphins to relocate or deal with food shortages as over fishing is becoming an increasing issues in certain areas.