The size of this species ranges from 2.5 to 3.5 m, depending on geographic
location. Since there are physiological differences between bottlenose dolphin
populations, this has caused disagreements over the genetic composition of the
species. It was assumed that there are around 20 different bottlenose species,
however contemporary scientific consensus is that there is one genus, although a
re-evaluation of this state of affairs is currently ongoing. The fact that bottlenose
dolphins and other toothed whales appear to interbreed makes the genetic differentiation increasingly difficult.
Bottlenose dolphins have displayed different migratory behaviours. While some
populations migrate, others are periodic resident species, or combine both migration
and local residency. They can often be found in coastal waters, in bays and estuaries,
and have also been sighted in rivers. Usually, bottlenose dolphins form groups of
2–15 individuals although very large groups of up to 1000 animals have been
observed. Amongst the groups, strong familial ties, sexual relationships and other
forms of individual affiliation exist. Like other dolphin groups, the bottlenose
dolphin communicates and navigates through clicking (echolocation), whistling
(individual sounds to communicate identity and location) and burst-pulse sounds
(“squawks” during social interactions).
Bottlenose dolphins have displayed a high degree of intelligence and make
frequent use of human infrastructure. For example, dolphins have been observed
driving schools of fish towards fishers in order to be able to hunt them more easily.
Bottlenose dolphins have also been trained for military purposes. They can frequently be seen following fishing trawlers, collecting discarded fish, or stealing fish
from fishing gear. Since the nineteenth century, but particularly during the twentieth
century, bottlenose dolphins have been part and parcel of aquariums and zoos
worldwide and dolphin shows are a common attraction (see Fig. 2.1).
21
One of the main contemporary sources for bottlenose and other dolphins is the
Japanese town of Taiji where the drive fishery is conducted for food and for
capturing dolphins for the international markets. Since 2015 the World Association
of Zoos and Aquariums (WAZA) has ordered its members to stop purchasing
dolphins from Taiji, which has resulted in some Japanese aquariums leaving the
Japanese branch of the organisation. While the capturing of dolphins was one reason,
Taiji’s large-scale and well-documented drive fishery is another. The Oscar-winning
documentary-like film The Cove by Louie Psihoyos from 2008 is an important
source for the influence on the public perception of the drive fishery. Although
several cinematic attempts have been made to counteract the claims made in The
Cove and even though the Japanese government has tried to justify the drive fishery
in the International Whaling Commission, international opposition that has translated into pressure on the Japanese government is significant.
22
However, Japan is not the only country hunting or having hunted bottlenose
dolphins. In the Black Sea, dolphins had been hunted extensively but the Black Sea
21 Wells and Scott (2008), pp. 249–255.
22 Sellheim (2017).
2.1 Whales
23
location. Since there are physiological differences between bottlenose dolphin
populations, this has caused disagreements over the genetic composition of the
species. It was assumed that there are around 20 different bottlenose species,
however contemporary scientific consensus is that there is one genus, although a
re-evaluation of this state of affairs is currently ongoing. The fact that bottlenose
dolphins and other toothed whales appear to interbreed makes the genetic differentiation increasingly difficult.
Bottlenose dolphins have displayed different migratory behaviours. While some
populations migrate, others are periodic resident species, or combine both migration
and local residency. They can often be found in coastal waters, in bays and estuaries,
and have also been sighted in rivers. Usually, bottlenose dolphins form groups of
2–15 individuals although very large groups of up to 1000 animals have been
observed. Amongst the groups, strong familial ties, sexual relationships and other
forms of individual affiliation exist. Like other dolphin groups, the bottlenose
dolphin communicates and navigates through clicking (echolocation), whistling
(individual sounds to communicate identity and location) and burst-pulse sounds
(“squawks” during social interactions).
Bottlenose dolphins have displayed a high degree of intelligence and make
frequent use of human infrastructure. For example, dolphins have been observed
driving schools of fish towards fishers in order to be able to hunt them more easily.
Bottlenose dolphins have also been trained for military purposes. They can frequently be seen following fishing trawlers, collecting discarded fish, or stealing fish
from fishing gear. Since the nineteenth century, but particularly during the twentieth
century, bottlenose dolphins have been part and parcel of aquariums and zoos
worldwide and dolphin shows are a common attraction (see Fig. 2.1).
21
One of the main contemporary sources for bottlenose and other dolphins is the
Japanese town of Taiji where the drive fishery is conducted for food and for
capturing dolphins for the international markets. Since 2015 the World Association
of Zoos and Aquariums (WAZA) has ordered its members to stop purchasing
dolphins from Taiji, which has resulted in some Japanese aquariums leaving the
Japanese branch of the organisation. While the capturing of dolphins was one reason,
Taiji’s large-scale and well-documented drive fishery is another. The Oscar-winning
documentary-like film The Cove by Louie Psihoyos from 2008 is an important
source for the influence on the public perception of the drive fishery. Although
several cinematic attempts have been made to counteract the claims made in The
Cove and even though the Japanese government has tried to justify the drive fishery
in the International Whaling Commission, international opposition that has translated into pressure on the Japanese government is significant.
22
However, Japan is not the only country hunting or having hunted bottlenose
dolphins. In the Black Sea, dolphins had been hunted extensively but the Black Sea
21 Wells and Scott (2008), pp. 249–255.
22 Sellheim (2017).
2.1 Whales
23