Pygmy Sperm Whale

*For dwarf sperm whale click here*

## About

A beached pygmy sperm whale.

The pygmy sperm whale ***(Kogia breviceps)*** is a species of odontocete whale, and one of two species belonging to the kogiidae family. Pygmy sperm whales are small in size, only growing 3.25-4.25m (10.66-13.94ft) in length and weighing 480kg (899lbs), which is extremely lightweight for a whale. Despite the pygmy sperm whale's tiny stature, the smallest whale is actually the closely related dwarf sperm whale ***(Kogia sima)***. In appearance pygmy sperm whales display countershading, having a dark back and light underbelly, which better allows them to camouflage from marine predators, as well as blend into the sea from above. Both the dwarf and pygmy sperm whales also have markings on either side of their face, known as false gills, as they superficially resemble the real gills of a fish. Apart from colour, the pygmy sperm whale has a very apparent square-shaped head, a characteristic found in both Kogiids. This bulbous head contains an organ that contains a fluid known as spermaceti. Originally thought to contain sperm, the spermaceti organ contains a waxy fluid, that magnifies the sounds that pygmy sperm whales make, in order to allow them to better echolocate. As pygmy sperm whales are carnivorous, they have a set of 12-16 thin teeth only present on their lower jaw, which fit into sockets on the upper jaw when closed. These teeth are extremely effective in catching and tearing apart food items. Interestingly, unlike the sperm whale ***(Physeter catodon)***, pygmy sperm whales can eject the liquid in its intestine similarly to a squid ejecting ink. This inking is further discussed in Behaviour.

## Diet

Pygmy sperm whales often prey on fish, crustaceans such as crabs and shrimps in particular, as well as octopus and squid species on occasion. Needle-like teeth on the whale's bottom jaw allows them to more easily catch their prey, as well as ensure that they cannot escape their mouths. Pygmy sperm whales will sometimes dive 304.8m (1000ft) in search of food.

## Conservation Status

Though pygmy sperm whales are listed as least concern by the IUCN, it is very possible that the species' population is smaller than estimated, and they are more accurately in much more danger. Little to no man-made threats endanger the pygmy sperm whale, with the exception of highly industrialised oceanic regions, which the whales prefer to stay clear from. Often whales are more prolifically killed by beaching themselves on coasts. It is unknown why they perform this act, whether it be purposeful or accidental however, interestingly most beached individuals are facing diseases, usually being quite sickly upon examination. The entanglement in fishing gear is also suspected to be a problem for pygmy sperm whales as well as whaling. Though whaling is not practiced in most countries due to international law, Indonesia, the Lesser Antilles and most notably Japan, still harpoon pygmy sperm whales for their meat and other properties.

## Range and Population

Pygmy sperm whales occur worldwide in almost every major ocean and marine region, inhabiting various temperatures and environments. The whales are however, rarely if ever recorded in more shallow marine regions, such as the Mediterranean, Red sea and Persian gulf for example. Pygmy sperm whales have a massive range, stretching to its northern most point in Canada and the United Kingdom, all the way to its southern most point in Australia, New Zealand, Argentina and South Africa. Other than their most abundantly found depth at 2km+ (1.2mi+), little to nothing is known about the pygmy sperm whale's preferred habitat, most likely due to the lack of live sightings as well as their often misidentification as dwarf sperm whales.

## Behaviour

The pygmy sperm is known to be almost entirely solitary however, has been spotted in small groups of around 6-7 individuals. These pods can vary in age and sex though, not much else is known about their social structure and organisation. Pygmy sperm whales also possess an 'ink sac' in their intestine, which contains dark reddish-brown secretion made up of ink and feces, which the whales can eject. When threatened the whales can release up to 11.35L (3ga) of this liquid, creating a dark cloud in which the whales can hide in or use as a distraction against predators. The ability to create this cloud is found exclusively in members of the Kogiidae family.

### Relationship with Humans

Pygmy sperm whales are extremely shy animals that do not try often to approach humans. Pygmy sperm whales also rarely approach motorised vessels, as they can often be struck by them if unseen. Motorised vessels also create noise pollution due to their loud motors, which greatly inhibit the whale's ability to navigate and hunt. The most dangerous side effect of noise pollution is however, the fact that it can prevent whales from understanding each other, causing dire problems surrounding migrations. Due to these circumstances, pygmy sperm whales are extremely hard to encounter and study. In fact, the pygmy and dwarf sperm whales were considered the same species until 1966, truly demonstrating how little knowledge we have surrounding these animals.

## In Captivity

No species of whale is currently kept in captivity, as they face issues surrounding welfare and stress. The captive keeping of Cetaceans has long been debated, and is currently considered quite unethical as captivity often negatively effects the mental state of these animals. Attempts have previously been made to keep pygmy sperm whales in captivity temporarily however, they soon die after entering facilities due to stress or pre-existing injuries. Despite all of the issues raised in reference to the welfare of the species, individuals have been kept in captive spaces however, they typically die quickly, with the longest surviving being 21 months.

## Sources

* IUCN Redlist of Threatened Species - https://www.iucnredlist.org/species/11047/50358334
* Pygmy Sperm Whale | NOAA Fisheries - https://www.fisheries.noaa.gov/species/pygmy-sperm-whale
* Pygmy Sperm Whale | Marine Bio - https://www.marinebio.org/species/pygmy-sperm-whales/kogia-breviceps/
* Pygmy Sperm Whale | Wikipedia - https://en.wikipedia.org/wiki/Pygmy\_sperm\_whale