Rorqual Whales of Galapagos

Category: Rorqual Whales
Family: Baleanopteridae

All 6 of the world's species or Rorqual whales have been recorded in Galapagos. The rorqual whales are large to very large, and include the biggest animals on earth. They differ from all other cetaceans in the region because they do not possess teeth. Instead, their upper jaws are lined with bony 'comb-like' plates called baleen which filter out small fish or zooplankton as the whale engulfs enormous quantities of seawater whilst swimming aIong. Rorquals have a double blowhole (single in toothed cetaceans), placed centrally on top of the head, a pleated throat capable of great expansion whilst feeding, a 'U'- to 'V'-shaped flattened head and a streamlined body for fast swimming.

MINKE WHALE

Scientific Name: Balaenoptera acutorostrata

Adult Length: 7-10 m (23 - 33 ft)
Blow: Small, vertical and bushy but usually not visible
Breaching: Variable angles
Deep dive: Tail flukes not raised
Group size: 1-2

Rare offshore

Identification:The smallest of its family, similar in size and shape to the beaked whales but its pointed snout, with a single ridge on the upper surface, distinguishes it from toothed cetaceans. Differs from other rorquals in its small size, lack of a tall blow, and large dorsal fin in relation to body length. Like the Sei Whale, the dorsal fin usually appears at the same time as the blowhole on surfacing. Many individuals show a white flipper band which is diagnostic.

SEI WHALE

Scientific Name: Balaenoptera borealis

Adult Length: 12-16 m (39 - 52 ft)
Blow: Tall, thin and vertical less robust than Fin Whale
Breaching: Seldom, generally rising at a low angle
Deep dive: Does not raise tail flukes
Group size: 1-2, sometimes more when feeding

Rare offshore

Identification: Very similar to Bryde's Whale both in size and appearance, but the single ridge on top of the head distinguishes it at close range. Differs from Minke Whale in Size and presence of tall, visible blow, and from Fin and Blue Whales by surfacing sequence and taller, more sickle-shaped fin. On surfacing, dorsal fin breaks the surface at the same time as the blowhole.

BRYDE'S WHALE

Scientific Name: Balaenoptera edeni

Adult Length: 11-15 m (36 - 49 ft)
Blow: Tall, thin and vertical
Breaching: Usually leaves water at a steep angle
Deep dive: Unlike Sei Whale, often arches tail stock before dive; does not raise tail flukes
Group size: 1-2, sometimes more when feeding

Frequent inshore and offshore

Identification: Easily confused with the Sei Whale due to its similar size, shape, and sickle-shaped dorsal fin. However, it possesses three lateral raised ridges on top of its head, a feature which distinguishes it from all other rorquals which only have a single ridge. The surfacing sequence is also unique, with the blowhole disappearing from view just before the fin appears. This feature alone should not be used for identification.

FIN WHALE

Scientific Name: Balaenoptera physalus

Adult Length: 18-26 m (59 - 85 ft)
Blow: Tall column, thicker and higher than Sei and Bryde's Whales but smaller than Blue Whale
Breaching: Variable angles, huge splash
Deep dive: Tail flukes not raised
Group Size: 1 - 2 ,sometimes more when feeding

Rare offshore

Identification: Second only to the Blue Whale in size, Fin Whales are similar to the other large rorquals. At close quarters, the asymmetrical pigmentation of the lower jaw is diagnostic. The left lower lip is dark, whilst the right is white. Surfacmg sequence is distinctive: appearance of blowhole precedes a rolling back, followed by the small but distinct sloping dorsal fin.

BLUE WHALE

Scientific Name: Balaenoptera musculus

Adult Length: 24 - 30 m (78 - 107 ft)
Blow: Largest of all: an enormous vertical column up to 10 m tall
Breaching: Only young known to breach, usually at 45° angle
Deep dive: Sometimes raises tail flukes
Group Size: 1 - 2, sometimes more when feeding

Rare offshore

Identification: The Blue Whale is the largest animal on the planet, but its size is not the easiest feature with which to distinguish it. lnstead, concentrate on surfacing sequence, fin size, and coloration. Confusion is most likely with the Fin Whale but on surfacing a Blue Whale exhales an even larger blow. The head then disappears to reveal a long rolling back before, finally, a tiny, stubby dorsal fin appears just before the animal sinks below the surface. Body color is bluish-grey but, unlike Fin Whale, it is usually covered with pale mottling.

HUMPBACK WHALE

Scientific Name: Megaptera novaeangliae

Adult Length: 11-15 m (36 - 49 ft)
Blow: Variable; tall, vertical and bushy
Breaching: Yes, usually landing on back
Deep dive: Body generally arches high before broad mil flukes are raised to reveal variable pale underside to tail
Group size: 1-3, sometimes more when feeding

Occasional inshore and offshore

Identification: Although similar to the other rorquals in size, the Humpback Whale is one of the most distinctive species. lts scientific name means 'Bigwinged New Englander', a description referring to its huge flippers which are over 3m long. Surfacing sequence is slow, the head is covered in raised knobs and the body is robust and bulky, with a low, sloping and broad-based dorsal fin. The back behind the fin, like the Sperm Whale, shows a series of knuckles along its ridge.