20121001_227 Blue whale.jpg

Blue whale, off Swami Rock, Trincomalee

Whale Species Information

Blue Whale

Length: 18-25m, max. 28m

Weight: 80-130t, max. >150t


Common all year round; peaking in March-April and less likely in June-July (austral winter).

Pelagic; migratory. The pygmy blue whale is a resident of the Indian Ocean. Inhabits continental slope areas to feed. Frequents the waters around submarine canyons such as those off Trincomalee, Dondra Head, Little Basses and Batticaloa. Besides the pygmy blue whale, the Antarctic blue whale may also be found in the northern Indian Ocean during the austral winter.

Common Names

English: blue whale, pygmy blue whale, Antarctic blue whale

Sinhala: nil thalmaha, nil thalmasa

Tamil: neelaththimingilam


Class: Mammalia                       Order: Cetacea

Suborder: Mysticeti                   Family: Balaenopteridae

Scientific name: Balaenoptera musculus (Linnaeus, 1758)

The blue whale can be confused with the other large rorquals. Although its great size may aid in identification, careful attention to colour pattern, head and dorsal fin shape, and dive behaviour will help distinguish it. The mottling colouration and small dorsal fin are diagnostic.

Taxonomic Notes

Blue whale subspecies in the northern Indian Ocean are not yet fully elucidated.


North Atlantic blue whale (B.m. musculus), Antarctic blue whale (B.m. intermedia), pygmy blue whale (B.m. brevicauda) and Indian blue whale (B.m. indica) have been described but the latter 2 are similar and only the first 3 are currently recognized (IUCN 2014).

The possible existence of separate populations of pygmy and Antarctic blue whales in the northern Indian Ocean requires further investigation. Analysis of whale calls suggests there may be three distinct subpopulations of a tropical subspecies in this region.


Some of the uncertainty surrounding the blue whale’s status, as a subspecies, resides in the problem of distinguishing (at sea) among them and populations (Reeves et al., 1998).

Bryde's Whale Complex (Bryde's Whale & Eden's Whale)

Length: 12-15m, max. 17m

Weight: 14-30t, max. 40t

Length: 6-13m, max. 14m

Weight: 14-25t, 30t

Common Names

English: Bryde’s whale 'complex', Bryde's whale, ordinary Bryde’s whale, offshore Bryde's whale, pygmy Bryde’s whale, Eden’s whale, small form Bryde's whale, large form Bryde's whale, smaller Indian fin whale.


Class: Mammalia                       Order: Cetacea

Suborder: Mysticeti                   Family: Balaenopteridae

Scientific name: Balaenoptera brydei, Olsen, 1913

                            Balaenoptera edeni, Anderson, 1878


Bryde's whales are found all year round. Regular; most frequent March-April (first intermonsoonal).


Resident and/or migratory. There may be two populations, one offshore and partly migratory, the other resident and found closer inshore.

Bryde's whale complex GPS records (POIs)
Taxonomic Notes

The “Bryde's whale complex” comprise two forms of rorqual: Bryde's whale (Balaenoptera brydei, Olsen, 1913) or B. e. brydei, a “large form” that occurs in warm temperate and tropical waters of the Indian, Pacific and Atlantic oceans, and Eden's whale (Balaenoptera edeni, Anderson, 1878) or B. e. edeni, a “small form” that may be restricted to the Indo-Pacific (Kershaw et al. 2013).


The identity and number of species in the “Bryde's Whale complex” is still unclear (Perrin & Brownell 2007, IUCN 2014). Thus, Balaenoptera edeni (Anderson, 1878) nomenclature is provisionally used in some publications for these two forms (B. brydei and B. edeni) until further genetic and morphological research may justify recognition of two species or subspecies.


The large form Bryde's whale (Bryde's whale) and small form Bryde's whale (Eden's whale) are believed to be two species within the Bryde's whale complex to be present in Sri Lankan waters. This nomenclature is provisional pending further scientific studies and classification.

For a detailed description on how to distinguish between the Bryde's whale and Eden's whale from other similar rorquals. Read more >>

Omura's Whale
Common Names

English: dwarf fin whale.


Class: Mammalia                       Order: Cetacea

Suborder: Mysticeti                   Family: Balaenopteridae

Scientific name: Balaenoptera omurai (Wada, Oishi & Yamada, 2003)




Two sightings recorded in April 2016 (Trincomalee) and February 2017 (Mirissa). Both sightings in shallow waters.

Omura’s whales mostly resemble the fin whale (Balaenoptera physalus) in external appearance but are much smaller. Attention to the several colour pattern features will help distinguish this rorqual. Its colouration and small dorsal fin are diagnostic.

Omura's whale Balaenoptera omurai Trincomalee
Sperm Whale

Length: 10-18m, max. 20m

Weight: 15-45t, max. >55t

Common Names

English: sperm whale.

Sinhala: komada, kuda varala komada

Tamil: vinthu thimingilam


Class: Mammalia                       Order: Cetacea

Suborder: Odontoceti                Family: Physeteridae

Scientific name: Physeter macrocephalus (Linnaeus, 1758)


Common all year round; abundant March-April, less frequent in June-July.

Nomadic, typically within a 1,500km (800nm) ‘home range’. May occur inshore when relocating but otherwise pelagic. Sperm whales prefer continental slopes and ridges characterized by high secondary production.

Sperm whales are generally easy to distinguish from other large whales at sea, even at a distance. The size of the prominent, angled blow easily sets them apart from the similarly-angled but smaller blow of Cuvier’s beaked whale. Humpback whales are the most similar to sperm whales physically, but confusion is only likely at a great distance, especially when they breach. Adult female sperm whales can be distinguished from adult males not only by their smaller size and weight but also from the light-coloured callosities sometimes visible on the tip of the dorsal fin. Males almost never possess this feature.

Sperm whale GPS records (POIs)