Heaviside's Dolphin
Cephalorhynchus heavisidii

Other Names: South African Dolphin, Benguela Dolphin

Habitat: Inshore

Status: Rare

Population: Unknown

Threats: Entanglement in fishing nets and hunting/whaling

Group Size: 2-3, temporary gatherings of up to 30

Fin Position: Slightly behind center

Newborns: c.34 in (85 cm), Unknown weight

Adults: 5 ¼-5 ¾ ft (1.6-1.7 m), 90-165 lbs. (40-75 kg)

Diet: Fish and occasionally squid or octopus

Teeth: 44 to 56 on both top and bottom rows

Description

Dorsal fin:

- prominent triangular fin
- broad base
- leading edge usually longer than trailing edge
- fin usually has straight or slightly concave trailing edge
- fin usually has slightly convex leading edge

Flukes:

- concave trailing edges
- distinct notch in middle
- flukes have "swept-back" appearance

Flippers:

- blunt tips sweep strongly backward
- small flippers

Head:

- dark oval patch around eye
- indistinct beak
- cone-shaped bead and flattened forehead
- dark area around blowhole, with dark line extending toward cape

Other characteristics:

- white "armpits"
- white diamond shape across chest
- dark blue-black back
- pale gray streak on each side
- stocky body tapers to tail
- white finger-shaped "lobe" points toward tail
- white underside
- sharp demarcation between white and black or gray markings
- front half of body uniformly gray

Behavior

- little is known about this species' behavior
- it is generally undemonstrative and appears to be shy
- breaching is rare, but it is known to leap more than 6 ½ ft (2 m) high
- has been observed doing rapid forward somersaults, which end in a tail-slap on the surface
- may porpoise when swimming at high speed
- reaction to vessels varies, but is known to approach a range of boats and to bow-ride and wake-ride; some animals have been seen "escorting" small vessels for several hours at a time
- limited observations suggest that at least some groups have restricted home ranges and probably do not stray far from these areas

Distribution

- coastal waters from southern South Africa northward to central Namibia
- range is restricted and fairly sparsely populated throughout
- occurs only off western coasts of South Africa and Namibia, along approximately 1,000 miles (1,600 km) of shoreline
- distribution known from Cape Cross, Namibia, but may extend as far north as southern Angola
- mostly seen in coastal waters, within 5-6 miles (8-10 km) of shore and in water less than 330 ft (100 m) deep
- surveys within 5 miles (8 km) of the coast have shown low population densities of around 5 sightings per 100 miles (160 km); sightings dropped dramatically farther offshore, and no animals were seen in water deeper than 655 ft (200 m)
- seems to be associated with the cold, northward-flowing Benguela Current
- some populations may be resident year-round


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This page was created by:Candice Orca Mottet