Whalecome to our new whales of the month: the dwarf and pygmy sperm whales. Like their cousin, the sperm whale, they like to spend most of their time deep underwater to hunt their favorite prey: squid and deep-sea fish, and crustaceans. Did you know they can release “ink” from their butts to confuse predators?! Find out more about these elusive whales in this new post.
Two very similar species
The Kogia genus includes both species covered this month: the dwarf sperm whale (Kogia sima) and the pygmy sperm whale (Kogia breviceps). Both whales are quite small compared to their 18m (60 ft) long cousin. Dwarf sperm whales reach a size of about 2.7m (9.5 ft), while pygmy sperm whales can reach 3.5m (11 ft). Both species also have a short head and snout jutting outwards. Like their bigger cousin, they only have teeth on their lower jaw, a blowhole leaning towards the left, and a spermaceti organ. This particular organ contains a waxy substance and is used to produce sounds for echolocation. Some experts also believe the spermaceti helps during dives by controlling the whale’s buoyancy.
A defensive technique borrowed from squids
Scientists believe that the two species feed by suction and target medium to deep-sea species like the glass squid as well as some deep-sea fish and crustaceans. Kogias themselves can be prey to killer whales and sharks. However, it seems that they borrowed a specific feature from squids to protect themselves from predator attacks. When afraid or threatened, both species can release some sort of “ink” from their butts; they are the only cetacean species capable of doing this. To do so, they contract a sac attached to the intestine and anus, which contains around 3 gallons (12 L) of a brown-reddish liquid. The release of the “ink” can distract a predator and allow the small whales to escape.
Both Kogia species are shy at the surface, making them hard to spot from a boat. They also spend most of their time foraging deep underwater. When they surface, they produce a little blow that is harder to spot than the big sperm whale’s blow. Their elusive nature makes it almost impossible to know how many Kogia whales are out there. Most of the information we have about these whales comes from individuals found dead on the shore.
Whalers hunted both dwarf and pygmy sperm whales in the 19th century. However, experts believe this hunting was quite negligible compared to sperm whales’ hunting because sperm whales were easier to spot, more massive, and produced more oil and ambergris. Some communities in Indonesia and the Lesser Antilles still hunt a couple of pygmy sperm whales today.
Contemporary threats include bycatch, entanglement, boat collisions, noise, and plastic pollution. It is not uncommon to find these little whales stranded on the coast with plastic bags blocking their intestines of trauma from a vessel strike. Their small sizes and shy natures make them unfortunate victims of marine traffic.
Did you enjoy this post on Kogia whales? Find out more about their cousin the sperm whale here:
A word about the illustrator, Markus Bühler:
“I have a life-long interest in living and extinct animals, particularly aquatic animals like fish, cetaceans, cephalopods, and various mammals, and reptiles. Since 2007 I’ve been writing on my blog Bestarium about various zoological and paleontological topics. I always try to cover unusual or little-known subjects. I also made a lot of model reconstructions of living and extinct animals, and in the past years, I gradually shifted towards digital illustration. One of my main intentions is to illustrate things that the public might ignore, like animal behavior never filmed or photographed, especially in marine mammals. I try to illustrate how these animals behave in their natural habitat and interact with other species as a part of their ecosystem.“
- Staudinger, M.D., McAlarney, R.J., McLellan, W.A. and Ann Pabst, D., 2014. Foraging ecology and niche overlap in pygmy (Kogia breviceps) and dwarf (Kogia sima) sperm whales from waters of the US mid‐Atlantic coast. Marine Mammal Science, 30(2), pp.626-655.
- Plön, S., 2004. The status and natural history of pygmy (Kogia breviceps) and dwarf (K. sima) sperm whales off Southern Africa (Doctoral dissertation, Rhodes University).
- Willis, P.M. and Baird, R.W., 1998. Status of the dwarf sperm whale, Kogia simus, with special reference to Canada. Canadian Field-Naturalist, 112(1), pp.114-125.
- McAlpine, D.F., 2018. Pygmy and dwarf sperm whales: Kogia breviceps and K. sima. In Encyclopedia of marine mammals (pp. 786-788). Academic Press.
- Markus Bühler’s posts about kogia and their ink clouds.