Pygmy beaked whale (Mesoplodon peruvianus)
|Also known as:||lesser beaked whale, Peruvian beaked whale|
|Size||Adult length: 3.7 - 3.9 m (2) (3)|
Calf length: 1.6 m (4)
- The pygmy beaked whale is the smallest known beaked whale.
- Although very little is known about the pygmy beaked whale, it is thought to be endemic to the warm temperate and tropical waters of the eastern Pacific Ocean.
- The male pygmy beaked whale can be distinguished from the female by a light brown or whitish band between the head and dorsal fin, and by its two protruding teeth.
- Accidental capture in gillnets is thought to be the most significant threat to the pygmy beaked whale.
The pygmy beaked whale is classified as Data Deficient (DD) on the IUCN Red List (1), and is listed on Appendix II of CITES (5).
At less than four metres in length, the pygmy beaked whale (Mesoplodon peruvianus) is the smallest known beaked whale (3) (6), and it is believed to be endemic to the warm temperate and tropical waters of the eastern Pacific Ocean (2). Sadly, the initial discovery of this species in 1991 came from ten specimens which were either stranded or captured along the Peruvian coast (3).
The pygmy beaked whale is slender and spindle-shaped (2) with a small, narrow head (2) (6), a short, thin beak (6), and characteristically small teeth which are egg-shaped in cross-section (3) (7). Its melon, the fatty organ found in the forehead used in echolocation, bulges less than in some other beaked whale species (6), and its small, triangular dorsal fin (2) (6) (7) is much like that of the harbour porpoise (Phocoena phocoena) (2) (7), with slightly curved or straight trailing edges (7). The petite size of the pygmy beaked whale is also reflected in its flippers, which are small and are dark in colour (2).
Female and juvenile pygmy beaked whales tend to have a uniform grey (3) or dark olive-brown to grey-brown colouration on the head and upper body, which fades to whitish-grey on the lower flanks and belly (2). Although males are similar in colour (2), they can be distinguished by extensive scarring on the upper body (2) (7) and by a wide, slanting, light brown to whitish band visible around the body between the head and the dorsal fin (2). The male pygmy beaked whale is thought to be slightly bigger than the female (7), and also has a more noticeably curved jawline, with two distinct teeth being visible halfway along the jaw. The male also has a more developed melon than the female (2).
It is believed that the pygmy beaked whale may be endemic to the eastern Pacific, meaning it does not live outside of the tropical or warm temperate waters of this area (1) (4). The range of the pygmy beaked whale is thought to extend from the Gulf of California south to Peru, although the northernmost and southernmost sightings reported have been off the coasts of California and Chile, respectively (4). There was also a record of a pygmy beaked whale beached in New Zealand, although this is believed to be an exceptional case (1).
Like other beaked whales, the pygmy beaked whale seems to prefer deep, warm waters, and inhabits the area beyond the continental shelf (1) (4). Most sightings of this whale appear to be in the ‘Eastern Pacific Warm Pool’, an area where surface water temperatures exceed 27.5 degrees Celsius (4).
Unfortunately, due to the lack of frequent sightings, little is known about the social structure or life history of the pygmy beaked whale, and no global estimates exist for its population abundance (1) (8). However, sightings suggest that the pygmy beaked whale lives in small social groups of between one and three individuals (2) (6). This is further supported by studies of Blainville’s beaked whales (Mesoplodon densirostris), which are closely related to the pygmy beaked whale and tend to live in a social group formed of approximately two or three individuals (8).
Much like other deep-water species, the pygmy beaked whale is thought to have a diet consisting of oceanic squid, shrimps and small fish (1). Like other toothed whales, such as those in the Mesoplodon genus, the pygmy beaked whale finds its prey using echolocation (9), which means that it produces sound and uses the echo to create a picture of the world around it and locate potential food items (10).
The pygmy beaked whale is subject to the common threats affecting many beaked whales, such as the anthropogenic (man-made) noise produced by military sonar, which is believed to be one cause of the past strandings of certain groups of whales (1) (4) (11).
Gillnets used to catch fish, either by entangling them or hooking onto their gills (12), are the most significant threat to the pygmy beaked whale, which ends up as bycatch in these deep-water nets (4).
Other threats to the pygmy beaked whale include the consumption of plastic items, which could lead to death, and also the predicted impact of climate change on the marine environment which this whale inhabits. The IUCN Red List states that the pygmy beaked whale is a relatively uncommon species, and should be considered potentially vulnerable to low-level threats (1).
As not much is known about the pygmy beaked whale, there are currently no specific conservation projects targeted at it, and so further research is needed (1). However, the species is listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), which means there should be careful monitoring and control of international trade in place for this species (5).
Find out more about the pygmy beaked whale:
Whale and Dolphin Conservation Society - Pygmy beaked whale:
Convention on Migratory Species - Mesoplodon peruvianus:
This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
- Bycatch: in the fishing industry, the part of the catch made up of non-target species.
- Continental shelf: a region of relatively shallow water, not usually deeper than 200 metres, surrounding each of the continents.
- Dorsal fin: the unpaired fin found on the back of the body of fish, or the raised structure on the back of most cetaceans (whales, dolphins and porpoises).
- Echolocation: detecting objects by reflected sound. Used by bats and odontocete cetaceans (toothed whales, dolphins and porpoises) for orientation and to detect and locate prey.
- Endemic: a species or taxonomic group that is only found in one particular country or geographic area.
- Genus: a category used in taxonomy, which is below ‘family’ and above ‘species’. A genus tends to contain species that have characteristics in common. The genus forms the first part of a ‘binomial’ Latin species name; the second part is the specific name.
- Melon: a lump of fatty tissue that forms the bulging forehead of toothed cetaceans (whales, dolphins and porpoises) and which is thought to focus sound during echolocation.
IUCN Red List (November, 2012)
Whale and Dolphin Conservation Society - Pygmy beaked whale (November, 2012)
- Reyes, J., Mead, G. and Van Waerebeek, K. (1991) A new species of beaked whale Mesoplodon peruvianus sp. N. (Cetacea: Ziphiidae) from Peru. Marine Mammal Science, 7(1): 1-24.
- Pitman, R.L. and Brownell Jr, R.L. (November, 2012) Review of Current Knowledge on Pygmy Beaked Whale Mesoplodon peruvianus Including Identification of Knowledge Gaps and Suggestions for Future Research. Scientific Committee 64, Small Cetaceans 30, International Whaling Commission.
CITES (July, 2013)
Convention on Migratory Species - Mesoplodon peruvianus (November, 2012)
MarineBio Conservation Society - Pygmy beaked whales (November, 2012)
Macleod, C.D. and D’Amico, A. (2006) A review of beaked whale behaviour and ecology in relation to assessing and mitigating impacts of anthropogenic noise. Journal of Cetacean Research and Management, 7(3): 211-221. Available at:
Johnson, M., Madsen, P.T., Zimmer, W.M.X., Aguilar de Soto, N. and Tyack, P.L. (2004) Beaked whales echolocate on prey. Proceedings of the Royal Society of London B, 271: 383-386. Available at:
NOAA Fisheries - Alaska Fisheries Science Center (July, 2013)
Cox, T.M. et al. (2006) Understanding the impacts of anthropogenic sound on beaked whales. Journal of Cetacean Research and Management, 7(3):177-187. Available at:
Food and Agriculture Organization of the United Nations: Fisheries and Aquaculture Department - Fishing Gear Types (November, 2012)