Rough-toothed Dolphin: where and when to see them

The rough-toothed dolphin is a warm-water oceanic dolphin with a distinctive, smoothly sloping forehead. Its name describes fine ridges on the teeth rather than anything obvious in a distant view. Often associated with deep tropical and subtropical waters, it can occur relatively close to steep oceanic islands. Cape Verde lies within its Atlantic range, but animals remain mobile and cannot be expected at any particular coastal viewpoint.

Size

2.1–2.8 m long

Weight

90–160 kg

Lifespan

Not reliably established

Status

Least Concern

Rough-toothed dolphins commonly travel in cohesive groups, sometimes swimming abreast with unusually synchronized surfacing. Groups may associate with other dolphins and occasionally larger cetaceans. Individuals cooperate while feeding and can handle comparatively large fish. Their surface activity varies from quiet, low-profile travel to conspicuous leaps, so distant observers may notice only brief dorsal fins or a sequence of coordinated surfacings rather than sustained displays. Rough-toothed dolphins sometimes perform 'porpoising' leaps, clearing the water entirely, but often maintain a lower profile. They are known to be active at the surface and have been observed 'wake-riding' alongside vessels, though this is not as common as with some other dolphin species.

• The teeth carry fine longitudinal enamel ridges.
• Its genus, Steno, contains only this living species.
• Groups can surface in remarkably close synchronization.
• Older individuals often show conspicuous pale scars and mottling.

No well-supported, species-specific shore-observation peak is established for Cape Verde. Clear visibility and calm seas improve distant detection whenever animals pass. Seasonal travel conditions should not be mistaken for a breeding season or evidence that dolphins favor a particular month. Cape Verde's dry season, typically from November to July, offers the calmest seas and best viewing conditions for marine life. While no specific season guarantees sightings, longer voyages during these months increase the probability of encountering these pelagic dolphins.

This species mainly occupies deep tropical and subtropical ocean waters, including steep island slopes where deep water approaches the coast. It is not a land animal or a dependable inhabitant of sheltered beaches. Distribution follows oceanic conditions and prey availability. Though generally oceanic, the species occasionally ventures into shallower waters over continental shelves and near oceanic islands. They are known to range throughout the Atlantic, Pacific, and Indian Oceans.

Fish and squid comprise the diet, including sizable oceanic fish such as dolphinfish in some studied populations. Cooperative handling and sharing of large prey have been documented. The relative importance of particular prey differs among regions and remains incompletely studied. Their dentition, featuring longitudinal ridges on the teeth, is well-adapted for grasping slippery prey. Individuals consume a variety of cephalopods and bony fish, with diet varying geographically based on local prey availability.

Common name

Rough-toothed Dolphin

Scientific name

Steno bredanensis

Animal group

Marine life

Size

2.1–2.8 m long

Weight

90–160 kg

Lifespan

Not reliably established

Status

Least Concern

Identification

Unlike bottlenose dolphins, rough-toothed dolphins have a long beak merging smoothly into a conical forehead without a pronounced crease. Their unique head shape gives them a primitive appearance, differing from the more rounded or distinctively beaked profiles of other dolphins. Adults often develop distinctive scars, especially around the head, and may appear mottled.