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LatestPhoto
A pod of Pilot whales logging at the surface.

Watch a short video of the long-finned pilot whales on the bow of the Odyssey.
Real Video   56k   200k
Photo : Chris Johnson

October 7, 2004
An Encounter with Long-finned Pilot Whales


Log Transcript

This is Genevieve Johnson speaking to you from the Odyssey in the Ligurian Sea in Italy.

It was late morning when the call came down from the observation platform - "pilot whales at 2 o'clock, 800 meters". We turned toward the group, realizing there were actually three groups - each several hundred meters apart.

Pilot whales are large dolphins that are widely distributed throughout the world's seas and oceans. Two species are currently recognized. As a general rule, short-finned pilot whales (Globicephala macrorhynchus) have a tropical and sub-tropical distribution, while the long-finned pilot whale (Globicephala melas) is found in temperate regions. There appears to be little overlap between the two types.

The name 'pilot whale' originated from the early theory that a leader pilots the school. The genus name, Globicephala, is derived from the Latin word 'globus', meaning round ball or globe while the Greek work 'kephale' meaning head. Apart from distribution, differences between the two species are subtle, the most obvious difference being fin length as their names suggest.

LatestPhoto
A pilot whale calf eyes the crew on the bow.
Photo : Chris Johnson

Notable aspects in natural history of pilot whale include striking sexual dimorphism similar to sperm whales and killer whales. Males reach a greater length with a much larger dorsal fin and a greatly pronounced melon. Pilot whales are also well known for their unexplained propensity to strand in large numbers.

The sea was flat and the animals 'logged' at the surface of the sea with their trademark dorsal fins appearing like a legion of black sails. All were quiet, motionless and facing the same direction. We did not detect any sound through our acoustic array. This is typical behavior from these animals when resting.

We turned off the engine within 200 meters, drifting parallel and taking several shots for photo-identification purposes. We began to hear some clicks and whistles on our underwater microphone as a group of 20-25 animals made their way toward Odyssey. This was the beginning of a remarkable four-hour encounter - one of the most unique of the expedition.

The group surrounded Odyssey and included individuals of all ages and both sexes. At least three animals displayed the massive dorsal fins of adult males and there were several juveniles. However, the most delightful were the mother and calf pairs. Among the three small calves, one was particularly small, less than two meters long and very light in color, an indication of its recent birth.

Adult male pilot whales reach an average length of 6 meters, changing from light brown to black as they mature. Perhaps their most distinctive feature and what made them instantly recognizable to the crew from a distance is their wide, broad-based dorsal fin. Most individuals have a faint gray saddle patch and a distinctive anchor-shaped chest patch.

LatestPhoto
The pod of long-finned pilot whales crowd around the bow as the Odyssey drifts.

Listen to the pilot whale vocalizations recorded on the acoustic array.
Real Audio
  28k   64k
Photo : Chris Johnson

All the animals seemed intent on crowding as closely as possible around the bow of the boat, rolling on their sides, spy-hopping, swimming on their bellies and slapping their long pectoral fins while looking up at the awe-struck crew leaning over, taking notes on their behavior. At times, so many animals swarmed around the bow, 6-7 animals swam on top of one other. A second group came to join in and after half an hour we counted between 45 - 50 animals drifting together with Odyssey over a clear Mediterranean Sea with nothing but the gentle rustle of the sail and a chorus of blows to pierce the silence - a perfect moment.

The echolocation clicks and whistles recorded by our acoustic array (underwater microphone) increased in intensity and volume. We heard the whistles from above the surface as we leaned over the railing of the ship. Several animals made gurgling sounds and blew bubbles through their blowholes. We observed the whales actually stroking one another with their pectoral fins across the bodies, fins and tail flukes of their companions - these animals were exceptionally tactile.

Three hours passed with the whales showing no inclination to leave us. We noticed the animals gradually becoming more active and excited, particularly the larger males, who increasingly demonstrated long bloody rake marks across their backs and dorsal fins. These were teeth marks from other animals in the group. The whales were mating.

We watched the animals swim belly to belly, while others seemed to pursue a less cooperative individual. After a while, small groups broke away from Odyssey, we observed a brief fury of white water and tail slapping as five or six animals writhed near the surface.

Much to the delight of the crew, the calves seemed oblivious to the excitement going on around them and were content to stay beneath the bow. They played around their mothers, testing their boundaries and charging others in the group, yet always returning to their mother's side after a few seconds. The mothers kept a watchful eye on their boisterous young, appearing completely content for them to approach and even touch Odyssey. It was a poignant reminder that no matter what the species, the young are always playful and mischievous.

LatestPhoto
An underwater view of the pod.
Photo : Genevieve Johnson

Later, one of the large males was directly beneath the bobstay; surrounded by the writhing assembly of his group. Just as he rose to breath, Odyssey dipped gently in the swell, the dorsal fin of the whale touched the bobstay (chain) setting into motion an ear piercing set of vocalizations and agitated barrel roles. Several animals seemed to respond acoustically and rush to his side, reassuring flippers extended as they stroked his flanks. After almost 30 seconds, the group seemed to settle, returning to their relaxed positions under and on either side of the bow.

The question on everybody's mind was - "Why are these animals so determined to stay with us?"
Of course we have no way of knowing, but perhaps it was a curious interruption in an otherwise monotonous day. This species is not sighted regularly in the Ligurian Sea, and perhaps they experience few encounters with boats, especially one that is drifting. The crew sees pilot whales in most seas and oceans we visit, but never witnessed such behavior. Usually these whales bow ride for a few minutes or swim in our wake showing nothing more than a passing interest in the boat.

Like most Odontocetes (toothed whales), pilot whales are highly social animals and are commonly found in pods of 20 - 100 animals. Composed of individuals with close matrilineal associations, groups tend to remain stable with most animals of both sexes remaining with their natal group for life.

At four o'clock, the whales were still with us. I am quite sure the crew would have happily stayed with them for the following week. However, the sound of distant sperm whale clicks demanded our attention and we reluctantly bid our companions farewell.

It is estimated there are a few hundred thousand long-finned pilot whales in the Atlantic Ocean alone. However, drive fisheries for this species exist in the Faroe Islands. In addition, hundreds of animals die each year from entanglements in long-lines, trawls and gill nets, while the build up of Persistent Organic Pollutants (POP's) in their tissue has an unknown effect on the population.

LatestPhoto
An underwater view of the pod.
Photo : Genevieve Johnson

Over a four-hour period we collected behavioral data, four continuous hours of acoustic recordings and hundreds of photographs that will be used to identify individuals. Our time with these animals gave the crew a relatively brief but exceptional glimpse into the realm of the pilot whale.

Links:

Log written by Genevieve Johnson.

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