Peale's dolphin (Cephalorhynchus australis)

In brief

The Peale’s dolphin is a small, stocky delphinid endemic to the cold temperate and subantarctic waters of the South American continental shelf, from Patagonia to Tierra del Fuego, Cape Horn and the Falkland Islands. It is recognised by its dark chin, by the two white “armpit” patches behind the flippers and by its large falcate dorsal fin; it spends much of its time in coastal kelp forests, where it hunts in coordinated groups. Listed as Least Concern on the IUCN Red List since 2019, it remains one of the least studied southern dolphins.

Identification

The Peale’s dolphin is a delphinid of modest size but massive build: the body is fusiform and thick, extended by a short rostrum barely set off from the melon. Adults generally measure 1.9 to 2.1 m, a maximum of about 2.2 m having been reported; the largest specimens measured in Tierra del Fuego reached 2.10 m for a female and 2.05 m for a male, while the asymptotic length, the size beyond which growth becomes negligible, stands at around 1.88 m. The highest recorded mass is close to 115 kg, and the newborn measures about 1 m. The dorsal fin, large, markedly falcate and able to reach 50 cm in height, is one of the best field characters. The flippers are pointed and curved like a crescent; mature animals bear small protuberances on their leading edge. The jaws hold a large number of small pointed teeth, up to about 37 in the upper row and 36 in the lower row.

The coloration combines three tones. The back, the dorsal fin and the flippers are very dark grey to black, the belly is white, and a broad pale grey area occupies the flanks, rising to a point from the rear of the body towards the front. A whitish band begins behind the dorsal fin and widens towards the tail stock. Two markings are particularly diagnostic: on the one hand the dark throat and chin, which gave the species its English name of black-chinned dolphin; on the other the two sharply defined white patches immediately behind the insertion of the flippers, often described as white “armpits”. A dark double eye ring extends towards the rostrum. Juveniles are on the whole paler than adults.

Over much of its range, the Peale’s dolphin occurs alongside other small southern delphinids. The Commerson’s dolphin (Cephalorhynchus commersonii), smaller and plainly two-toned black and white with no intermediate shade of grey, is hardly a source of confusion in good light. The risk is more real with the dusky dolphin (long known as Lagenorhynchus obscurus), of comparable size and also present on the Argentine coast: the pale pattern on its flanks splits into two tapering bands that rise in a fork towards the dorsal fin, whereas that of the Peale’s dolphin stays more compact and more contrasted; above all, the white axillary patches are absent in the dusky dolphin. The hourglass dolphin (Cephalorhynchus cruciger), with its hourglass marking, is for its part essentially oceanic and subantarctic and seldom enters the coastal shelf.

Taxonomy

The species was described by the American naturalist Titian Ramsay Peale from material collected during the United States Exploring Expedition; it is cited under the authority (Peale, 1849), some sources giving 1848, the year the original volume was printed. It belongs to the family Delphinidae, within the suborder of odontocetes.

Long placed in the genus Lagenorhynchus under the name Lagenorhynchus australis, a label still omnipresent in the scientific literature and in databases, it has been the subject of a thorough taxonomic revision. Molecular analyses have shown that the genus Lagenorhynchus, as it was constituted, was polyphyletic: it brought together species that did not share an exclusive common ancestor. Vollmer and colleagues (2019) proposed restricting Lagenorhynchus to the white-beaked dolphin alone (L. albirostris) and transferring the Atlantic white-sided dolphin to the genus Leucopleurus. Galatius and colleagues (2025) took the revision further by showing that the Peale’s dolphin and the hourglass dolphin are more closely related to the four species of the genus Cephalorhynchus than to the other Lagenorhynchus, and moved them there. The genus Sagmatias, of which australis was the type species, thereby falls into synonymy with Cephalorhynchus, and a new genus, Aethalodelphis, has been erected for the dusky dolphin and the Pacific white-sided dolphin. The reference list of the Society for Marine Mammalogy today retains Cephalorhynchus australis (Peale, 1849). This proximity to the Cephalorhynchus is consistent with a shared acoustic trait: the emission of narrow-band high-frequency clicks.

Distribution and habitat

The Peale’s dolphin is endemic to the cold temperate and subantarctic waters of the southern cone of South America. On the Pacific side, it ranges up along Chile at least as far as the Valdivia region (about 40° S), with more northerly sightings reported as far as the vicinity of Valparaíso (about 33° S). On the Atlantic side, it occupies the Patagonian shelf northwards to the south of Buenos Aires Province (about 38° S), densities becoming markedly lower north of the Gulf of San Jorge. The core of the range corresponds to the Strait of Magellan, the Fuegian channels, the Beagle Channel and Cape Horn (about 56° S), as well as the Falkland / Malvinas archipelago, where the species is regularly sighted close inshore.

It is an animal of the continental shelf and the coastal fringe. During the Argentine surveys, 98.5% of sightings were over depths of less than 200 m, in surface waters between 5 and 14.5 °C, with habitat models indicating a preference for temperatures of 9 to 18 °C, and at distances from the coast ranging from about 3.5 to 300 km. It favours sheltered bays, the entrances of channels and fjords, areas of strong tidal currents and above all kelp forests, where it hunts and travels. In the Falklands, habitat models place it slightly further offshore than the Commerson’s dolphin, with aggregations some 2 km from the kelp beds and from the shore, mainly to the south and north-west of the archipelago.

Spatial models applied to eight surveys carried out between 2009 and 2015 on the Argentine Patagonian shelf put the population at close to 19,900 individuals (95% confidence interval: about 12,900 to 30,800), with two cores of high density, one to the east of the Gulf of San Jorge, the other to the south of the Tierra del Fuego archipelago. No global estimate covering the whole of the range is available.

The Peale’s dolphin is absent from French waters. It is seen neither in the Mediterranean, nor in the Bay of Biscay, nor in the English Channel, nor in the overseas collectivities: its range is limited to the South American continental shelf and the archipelagos that border it.

Biology and ecology

The diet is carnivorous and opportunistic. It rests largely on demersal and benthic fish, hakes, Patagonian grenadier (Macruronus magellanicus), southern cods, supplemented by octopus, squid, shrimp and various crustaceans. Hunting is often collective: the dolphins encircle a shoal of prey in formations described as “star” or “flower” shaped, or else in straight lines, before taking turns to feed. These sequences frequently take place directly above or at the edge of kelp forests, which concentrate prey and probably serve as a structure for herding them.

Social life is organised in small groups, of 2 to 10 animals most often, with a mean of 2 to 4 individuals in some areas. Gatherings of 20 to 30 dolphins are regular, and exceptional aggregations of about a hundred individuals have been reported in the austral summer and autumn. Groups readily move parallel to the shore, alternating slow swimming with phases of intense activity made up of breaches, spins and lobtailing. Mixed associations with the Commerson’s dolphin are documented. The species shows curiosity towards boats and rides bow waves. The breathing rhythm is calm: the animals surface three to four times a minute and their dives last from 1 to 130 seconds, generally less than a minute.

Acoustically, the Peale’s dolphin was long placed among the so-called NBHF (narrow-band high frequency) species, which emit narrow-band high-frequency clicks and are reputed to lack whistles. In the Strait of Magellan, recordings made in December 2021 yielded more than 14,000 clicks, with a peak frequency of 131 ± 11 kHz and a centroid frequency of 138 ± 9 kHz, together with three distinct modes around 122, 133 and 170 kHz; acoustic activity there was about 2.3 times more intense at night than by day. Work carried out in the Falklands has nevertheless shown that the species also produces genuine tonal whistles, of 0.10 to 1.41 s in duration and with a mean fundamental frequency ranging from 4.8 to 7.6 kHz, accompanied by broadband clicks. The Peale’s dolphin thus has a mixed repertoire, able to depart from the acoustic discretion characteristic of NBHF species.

Breeding remains poorly known. Births are spread from October to April, that is from the austral spring to the austral autumn, after a gestation estimated at between 10 and 12 months. The female gives birth to a single calf of about 1 m, suckled for approximately 18 months; independence appears to be reached at around two years. The age at sexual maturity is not established. The study of a collection of 57 skeletons, coming mostly from Tierra del Fuego, of which 23 could be aged by reading the dental growth layers, yielded a maximum age of 13 years for a 1.99 m female; only two animals, of 12 and 13 years, were physically mature. This sample is too small to define the real longevity of the species. No natural predator is formally documented.

Status and conservation

The Peale’s dolphin is listed as Least Concern (LC) on the IUCN Red List, following an assessment published in March 2019. It had previously been listed as Data Deficient (DD): this reclassification reflects the application of a new IUCN policy on the interpretation of the DD category, and not a demonstrated improvement in the state of the populations. No subpopulation is assessed separately. The species is listed in Appendix II of CITES, which regulates international trade, and in Appendix II of the Convention on Migratory Species (CMS).

The heaviest historical pressure has been its use as bait. In the 1970s and 1980s, thousands of small cetaceans, mainly Commerson’s dolphins and Peale’s dolphins, were harpooned each year in Chile and Argentina to supply the southern king crab fisheries, the centolla (Lithodes santolla) and the centollón (Paralomis granulosa). This practice has declined sharply, partly because of the overexploitation of the crab stocks themselves, but residual cases are still reported.

Today, the main threats are bycatch in coastal gillnets, reported in the Strait of Magellan, in Tierra del Fuego and in the Argentine province of Santa Cruz, together with entanglement in the anti-predator nets of Chilean salmon farms. To these are added the degradation of coastal habitat linked to urban and port development, to aquaculture, to oil and gas activities, to the intensification of shipping traffic and to pollution. The strongly coastal character of the species, its restricted range and its dependence on kelp forests increase its vulnerability, all the more so since the real extent of bycatch remains poorly quantified.

On the regulatory side, Chile adopted in 2008 Law No. 20.293, which declares the whole of its maritime space a zone free of cetacean hunting and prohibits killing, capturing, harassing, holding, transporting, processing or trading any cetacean frequenting those waters. The conservation priority identified remains the improvement of knowledge: monitoring of numbers, quantification of accidental mortality and identification of any distinct population structure.

Observing this species

The Peale’s dolphin is among the most accessible cetaceans of southern Patagonia, including from dry land. The Beagle Channel out of Ushuaia (Argentina), the Strait of Magellan around Punta Arenas (Chile), the Fuegian channels and the coasts of the Falklands offer the best chances of an encounter. The species readily shows curiosity towards boats and often comes to ride the bow wave, which makes it easier to identify the white axillary patches and the dark chin.

The austral summer and autumn, from November to April, account for most boat trips and scientific surveys, and this is also the period when the largest gatherings have been noted. To maximise one’s chances, it is worth scanning the edges of kelp forests, the entrances of channels and fjords and the areas of tidal currents, where the animals hunt. From the shore, a high point overlooking a sheltered bay makes an effective observation post; binoculars are enough, as the species often moves a few hundred metres from the shore.

A few ethical rules apply, all the more so since the groups are small and faithful to restricted sectors. One should approach slowly and from the side, never head-on or from behind, keep a constant speed and course, and avoid cutting across the path of the animals or splitting a group, particularly when young are present. The approach should be kept brief, and the engine slowed or put into neutral if the dolphins come towards the boat of their own accord. They should not be fed, nor should anyone try to swim with them or pursue them if they move away. Reporting sightings to local monitoring bodies is a useful contribution to filling the data gap that still characterises this species.

Frequently asked questions

Why is the Peale’s dolphin found under several different scientific names?

Because its classification has been revised recently. Described under the authority (Peale, 1849), it long bore the name Lagenorhynchus australis. Genetic analyses having shown that the old genus Lagenorhynchus brought together species not related to one another, it was first moved to the genus Sagmatias, then, following the work of Galatius and colleagues published in 2025, to the genus Cephalorhynchus, alongside the Commerson’s dolphin and the hourglass dolphin. The name Lagenorhynchus australis remains very widely used in the literature and in databases.

What size does the Peale’s dolphin reach?

Adults generally measure 1.9 to 2.1 m, a maximum of about 2.2 m having been reported. The asymptotic length, that is to say the size beyond which growth becomes negligible, is estimated at 1.88 m, and the largest specimens measured in Tierra del Fuego reached 2.10 m for a female and 2.05 m for a male. The highest recorded mass is close to 115 kg and the newborn measures about 1 m.

What exactly is its conservation status?

It is listed as Least Concern (LC) on the IUCN Red List following an assessment published in March 2019. It had previously been Data Deficient (DD); the change stems from a new IUCN policy on the use of that category, and not from a measured improvement in numbers. The species is also listed in Appendix II of CITES and in Appendix II of the Convention on Migratory Species.

How many Peale’s dolphins are left?

There is no estimate covering the whole of the range. The most solid reference comes from spatial models applied to eight surveys carried out between 2009 and 2015 on the Argentine Patagonian shelf, which estimate close to 19,900 individuals, with a 95% confidence interval running from about 12,900 to 30,800. The Chilean and Falkland populations are not included in that figure.

Can this species be seen in France?

No. The Peale’s dolphin is strictly confined to the continental shelf of southern South America, from central Chile to Cape Horn and as far as the Falkland Islands. It is absent from the Mediterranean, the Bay of Biscay, the English Channel and French overseas waters.

How can it be told apart from the dusky dolphin, with which it shares part of its range?

The most reliable character is the presence, in the Peale’s dolphin, of two sharply defined white patches just behind the insertion of the flippers, absent in the dusky dolphin. To these are added the distinctly dark throat and chin, and a more compact pale pattern on the flanks, whereas that of the dusky dolphin splits into two tapering bands rising in a fork towards the dorsal fin.

Does the Peale’s dolphin whistle?

Yes, although it was long regarded as a species that was silent in that respect. It emits mainly narrow-band high-frequency clicks, with a peak frequency measured at 131 ± 11 kHz in the Strait of Magellan. Recordings made in the Falkland Islands have nevertheless brought to light genuine tonal whistles, of 0.10 to 1.41 seconds in duration and with a mean fundamental frequency of between 4.8 and 7.6 kHz, as well as broadband clicks.

Sources

• https://www.iucnredlist.org/species/11143/50361589
• https://iucn-csg.org/5-updated-cetacean-red-list-assessments-published-in-march-2019/
• https://iucn-csg.org/red-list-status-of-cetaceans/
• https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/
• https://www.mammaldiversity.org/taxon/1006426/
• https://en.wikipedia.org/wiki/Peale%27s_dolphin
• https://fr.wikipedia.org/wiki/Dauphin_de_Peale
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• https://www.marinebio.org/species/peales-dolphins/lagenorhynchus-australis/
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• https://www.cetaces.org/especes/dauphin-austral/
• https://pmc.ncbi.nlm.nih.gov/articles/PMC5082685/
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• https://pmc.ncbi.nlm.nih.gov/articles/PMC12248228/
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Profile compiled from authoritative scientific sources (IUCN, NOAA Fisheries, specialist literature) and reviewed for factual accuracy.