Animal song is not a well-defined term in scientific literature, and the use of the more broadly defined term ''vocalizations'' is in more common use. Song generally consists of several successive vocal sounds incorporating multiple
syllables. Some sources distinguish between simpler vocalizations, termed “calls”, reserving the term “song” for more complex productions. Song-like productions have been identified in several groups of animals, including
cetaceans (
whale
Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and ...
s and
dolphin
A dolphin is an aquatic mammal within the infraorder Cetacea. Dolphin species belong to the families Delphinidae (the oceanic dolphins), Platanistidae (the Indian river dolphins), Iniidae (the New World river dolphins), Pontoporiidae (the ...
s),
avians (
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s),
anurans
A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-frog" ''Triadobatrachus'' is ...
(
frog
A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-frog" ''Triadobatrachus'' is ...
s), and
human
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, cultu ...
s. Social transmission of song has been found in groups including
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s and
cetaceans.
Anatomy of sound production
Mammals
Most
mammalian species produce sound by passing air from the
lungs across the
larynx, vibrating the
vocal folds
In humans, vocal cords, also known as vocal folds or voice reeds, are folds of throat tissues that are key in creating sounds through vocalization. The size of vocal cords affects the pitch of voice. Open when breathing and vibrating for speec ...
.
Sound then enters the supralaryngeal
vocal tract
The vocal tract is the cavity in human bodies and in animals where the sound produced at the sound source ( larynx in mammals; syrinx in birds) is filtered.
In birds it consists of the trachea, the syrinx, the oral cavity, the upper part of th ...
, which can be adjusted to produce various changes in sound output, providing refinement of vocalizations.
Although morphological differences between species affect production of
sound
In physics, sound is a vibration that propagates as an acoustic wave, through a transmission medium such as a gas, liquid or solid.
In human physiology and psychology, sound is the ''reception'' of such waves and their ''perception'' b ...
, neural control is thought to be more essential factor in producing the variations within
human speech
Speech is a human vocal communication using language. Each language uses phonetic combinations of vowel and consonant sounds that form the sound of its words (that is, all English words sound different from all French words, even if they are th ...
and song compared to those of other mammals.
Cetacean vocalizations are an exception to this general mechanism.
Toothed whale
The toothed whales (also called odontocetes, systematic name Odontoceti) are a parvorder of cetaceans that includes dolphins, porpoises, and all other whales possessing teeth, such as the beaked whales and sperm whales. Seventy-three species of ...
s (
Odontocetes
The toothed whales (also called odontocetes, systematic name Odontoceti) are a parvorder of cetaceans that includes dolphins, porpoises, and all other whales possessing teeth, such as the beaked whales and sperm whales. Seventy-three species of t ...
) pass air through a system of air sacs and muscular phonic lips, which vibrate to produce audible vocalizations, thus serving the function of
vocal folds
In humans, vocal cords, also known as vocal folds or voice reeds, are folds of throat tissues that are key in creating sounds through vocalization. The size of vocal cords affects the pitch of voice. Open when breathing and vibrating for speec ...
in other
mammals.
Sound vibrations are conveyed to an organ in the head called the
melon
A melon is any of various plants of the family Cucurbitaceae with sweet, edible, and fleshy fruit. The word "melon" can refer to either the plant or specifically to the fruit. Botanically, a melon is a kind of berry, specifically a " pepo". Th ...
, which can be changed in shape to control and direct vocalizations. Unlike in
human
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, cultu ...
s and other
mammals,
toothed whale
The toothed whales (also called odontocetes, systematic name Odontoceti) are a parvorder of cetaceans that includes dolphins, porpoises, and all other whales possessing teeth, such as the beaked whales and sperm whales. Seventy-three species of ...
s are able to recycle air used in vocal production, allowing
whale
Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and ...
s to sing without releasing air.
Some
cetaceans, such as
humpback whale
The humpback whale (''Megaptera novaeangliae'') is a species of baleen whale. It is a rorqual (a member of the family Balaenopteridae) and is the only species in the genus ''Megaptera''. Adults range in length from and weigh up to . The hu ...
s, sing continuously for hours.
Anurans
Like mammals,
anurans
A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-frog" ''Triadobatrachus'' is ...
possess a
larynx and
vocal folds
In humans, vocal cords, also known as vocal folds or voice reeds, are folds of throat tissues that are key in creating sounds through vocalization. The size of vocal cords affects the pitch of voice. Open when breathing and vibrating for speec ...
, which are used to create vibrations in sound production.
However,
frog
A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-frog" ''Triadobatrachus'' is ...
s also use structures called vocal sacs, elastic membranes in the base of the mouth which inflate during sound production.
These sacs provide both amplification and fine-tuning of sounds, and also allow air to be pushed back into the
lungs during vocalizations.
This allows air used in sound production to be recycled, and is thought to have evolved to increase song efficiency.
Increased efficiency of sound production is important, as some
frog
A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-frog" ''Triadobatrachus'' is ...
s may produce calls lasting for several hours during mating seasons.
The
New River tree frog (''
Trachycephalus hadroceps''), for example, spends hours producing up to 38,000 calls in a single night, which is made possible through the efficient recycling of air by the vocal sac.
Birds
When
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s inhale, air is passed from the mouth, through the
trachea
The trachea, also known as the windpipe, is a cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all air- breathing animals with lungs. The trachea extends from the ...
, which forks into two
bronchii connecting to the
lungs. The primary vocal organ of
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s is called the
syrinx, which is located at the fork of the
trachea
The trachea, also known as the windpipe, is a cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all air- breathing animals with lungs. The trachea extends from the ...
, and is not present in
mammals.
As air passes through the
respiratory tract, the
syrinx and the membranes within vibrate to produce sound.
Bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s are capable of producing continuous song during both
inhalation and
exhalation
Exhalation (or expiration) is the flow of the breath out of an organism. In animals, it is the movement of air from the lungs out of the airways, to the external environment during breathing.
This happens due to elastic properties of the lungs, ...
, and may sing continuously for several minutes. For example, the skylark (''
Alauda arvensis
The Eurasian skylark (''Alauda arvensis'') is a passerine bird in the lark family, Alaudidae. It is a widespread species found across Europe and the Palearctic with introduced populations in New Zealand, Australia and on the Hawaiian Islands. I ...
'') is capable of producing non-stop song for up to one hour. Some
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s change their song characteristics during
inhalation versus
exhalation
Exhalation (or expiration) is the flow of the breath out of an organism. In animals, it is the movement of air from the lungs out of the airways, to the external environment during breathing.
This happens due to elastic properties of the lungs, ...
. The
Brewer's sparrow (''
Spizella breweri'') alternates between rapid trilling during
exhalation
Exhalation (or expiration) is the flow of the breath out of an organism. In animals, it is the movement of air from the lungs out of the airways, to the external environment during breathing.
This happens due to elastic properties of the lungs, ...
interspersed with lower-rate trills during short
inhalations. The two halves of the
syrinx connect to separate
lungs, and can be controlled independently, allowing some birds to produce two separate notes simultaneously.
Insects
Insect
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three ...
s such as
crickets
Crickets are orthopteran insects which are related to bush crickets, and, more distantly, to grasshoppers. In older literature, such as Imms,Imms AD, rev. Richards OW & Davies RG (1970) ''A General Textbook of Entomology'' 9th Ed. Methuen 8 ...
(
family Gryllidae) are well known for their ability to produce loud song, however the mechanism of sound production differs greatly from most other animals. Many
insect
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three ...
s generate sound by mechanical rubbing of body structures, a mechanism known as
stridulation
Stridulation is the act of producing sound by rubbing together certain body parts. This behavior is mostly associated with insects, but other animals are known to do this as well, such as a number of species of fish, snakes and spiders. The mech ...
.
Orthopteran insects, including
crickets
Crickets are orthopteran insects which are related to bush crickets, and, more distantly, to grasshoppers. In older literature, such as Imms,Imms AD, rev. Richards OW & Davies RG (1970) ''A General Textbook of Entomology'' 9th Ed. Methuen 8 ...
and
katydids
Insects in the family Tettigoniidae are commonly called katydids (especially in North America), or bush crickets. They have previously been known as "long-horned grasshoppers". More than 8,000 species are known. Part of the suborder Ensifera, t ...
(family
Tettigoniidae
Insects in the family Tettigoniidae are commonly called katydids (especially in North America), or bush crickets. They have previously been known as "long-horned grasshoppers". More than 8,000 species are known. Part of the suborder Ensifera, ...
), have been especially well-studied for sound production. These insects use scraper-like structures on one wing to sweep over file-structures on an opposing wing to create vibrations, producing a variety of trilling and chirping sounds.
Locust
Locusts (derived from the Vulgar Latin ''locusta'', meaning grasshopper) are various species of short-horned grasshoppers in the family Acrididae that have a swarming phase. These insects are usually solitary, but under certain circumstanc ...
s and other
grasshoppers (suborder
Caelifera
The Caelifera are a suborder of orthopteran insects. They include the grasshoppers and grasshopper-like insects, as well as other superfamilies classified with them: the ground-hoppers (Tetrigoidea) and pygmy mole crickets ( Tridactyloidea). ...
)
stridulate by rubbing hind legs against pegs on wing surfaces in an up and downward motion.
Cicada
The cicadas () are a superfamily, the Cicadoidea, of insects in the order Hemiptera (true bugs). They are in the suborder Auchenorrhyncha, along with smaller jumping bugs such as leafhoppers and froghoppers. The superfamily is divided into tw ...
s (superfamily
Cicadoidea) produce sound at much greater volumes than
Orthopterans, relying on a pair of organs called
tymbal
The tymbal (or timbal) is the corrugated exoskeletal structure used to produce sounds in insects. In male cicadas, the tymbals are membranes in the abdomen, responsible for the characteristic sound produced by the insect. In tiger moths, the t ...
s on the base of the
abdomen
The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the to ...
behind the wings.
Muscle contraction rapidly deforms the
tymbal
The tymbal (or timbal) is the corrugated exoskeletal structure used to produce sounds in insects. In male cicadas, the tymbals are membranes in the abdomen, responsible for the characteristic sound produced by the insect. In tiger moths, the t ...
membrane, emitting several different types of sounds.
Insect
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three ...
s thus produce a variety of sounds, using various mechanisms distinct from other animals.
Functions of vocalizations
Vocalizations can play a wide variety of different roles. In groups such as
anurans
A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-frog" ''Triadobatrachus'' is ...
and
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s, several distinct types of notes are incorporated to form songs, which are sung in different situations and serve distinct functions.
For example, many
frog
A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-frog" ''Triadobatrachus'' is ...
s may use trilling notes in mate attraction, but switch to different vocal patterns in
aggressive
Aggression is overt or covert, often harmful, social interaction with the intention of inflicting damage or other harm upon another individual; although it can be channeled into creative and practical outlets for some. It may occur either reacti ...
territorial displays.
In some species, a single song incorporates several note types which serve different purposes, with one type of note eliciting responses from females, and another note of the same song responsible for warning competitor males of
aggression.
Mating and courtship
Vocalizations play an important role in the
mating behaviour of many animals. In many groups (
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s,
frog
A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-frog" ''Triadobatrachus'' is ...
s,
crickets
Crickets are orthopteran insects which are related to bush crickets, and, more distantly, to grasshoppers. In older literature, such as Imms,Imms AD, rev. Richards OW & Davies RG (1970) ''A General Textbook of Entomology'' 9th Ed. Methuen 8 ...
,
whale
Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and ...
s etc.), song production is more common in males of the species, and is often used to attract females.
Bird song is thought to have evolved through
sexual selection
Sexual selection is a mode of natural selection in which members of one biological sex choose mates of the other sex to mate with (intersexual selection), and compete with members of the same sex for access to members of the opposite sex ( ...
. Female
songbird
A songbird is a bird belonging to the suborder Passeri of the perching birds (Passeriformes). Another name that is sometimes seen as the scientific or vernacular name is Oscines, from Latin ''oscen'', "songbird". The Passeriformes contains 5000 ...
s often assess potential mates using song, based on qualities such as high song output, complexity and difficulty of songs, as well as presence of local dialect.
Song output serves as a
fitness indicator of males, since vocalizations require both energy and time to produce, and thus males capable of producing high song output for long durations may have higher
fitness than less vocal males.
It is thought that song complexity may serve as an indicator of male
fitness by providing an indication of successful brain development despite potential early-life stressors, such as lack of food.
Social transmission of songs allows for development of local dialects of song, and female songbirds also typically prefer to choose mates producing local song dialects.
One hypothesis for this phenomenon is that selecting local mates allows the female to choose genes specially adapted to suit local conditions.
Frog
A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-frog" ''Triadobatrachus'' is ...
song also plays a prominent role in
courtship
Courtship is the period wherein some couples get to know each other prior to a possible marriage. Courtship traditionally may begin after a betrothal and may conclude with the celebration of marriage. A courtship may be an informal and private m ...
. In
túngara frog
The Túngara frog (''Engystomops pustulosus'') is a species of frog in the family Leptodactylidae. It is a small nocturnal terrestrial frog found in Mexico, Central America, and the northeastern regions of South America.
The tungara frog exhib ...
s (''
Engystomops pustulosus
''Engystomops'' is a genus of frogs in the family Leptodactylidae. They are known commonly as foam frogs or túngara frogs, though the latter name most commonly refers to '' Engystomops pustulosus''. They are native to the Americas from southern ...
''), male
frog
A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-frog" ''Triadobatrachus'' is ...
s increase the complexity of their calls, adding additional note types when greater numbers of competitor males are present, which has been found to attract greater numbers of female frogs. Some species change their
courtship
Courtship is the period wherein some couples get to know each other prior to a possible marriage. Courtship traditionally may begin after a betrothal and may conclude with the celebration of marriage. A courtship may be an informal and private m ...
calls when females are especially nearby. In male
glass frogs (''Hyalinobatachium fleichmanni''), a long frequency-modulated vocalization is produced upon noticing another nearby
frog
A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-frog" ''Triadobatrachus'' is ...
, but is changed to a short chirping song when a female approaches.
Several species (e.g. dendrobatid frogs (''
Mannophryne trinitatis''),
ornate frogs (''
Cophixalus ornatus
''Cophixalus ornatus'', commonly known as the ornate nursery-frog, is a species of frog in the family Microhylidae. It is endemic to north-eastern Queensland
)
, nickname = Sunshine State
, image_map = Queensland in Australia.svg
, map_cap ...
''),
splendid poison frogs (''
Dendrobates speciosus'')), switch from long-range loud trilling sounds to short-range quieter chirps when females move closer, which is thought to allow mate attraction without alerting competitor males to female locations.
Although highly complex song-like production has been identified in
whale
Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and ...
s, the function is still somewhat elusive. It is thought to be involved in
courtship behaviour and
sexual selection
Sexual selection is a mode of natural selection in which members of one biological sex choose mates of the other sex to mate with (intersexual selection), and compete with members of the same sex for access to members of the opposite sex ( ...
, and singing behaviour becomes more common during the breeding season.
Aggression and territorial defense
Another major function of song output is to indicate aggression among males during breeding seasons. Both
anurans
A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-frog" ''Triadobatrachus'' is ...
and
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s use singing in territorial displays to confer
aggressive
Aggression is overt or covert, often harmful, social interaction with the intention of inflicting damage or other harm upon another individual; although it can be channeled into creative and practical outlets for some. It may occur either reacti ...
intent.
For
Eastern smooth frogs (''
Geocrinia victoriana''), for example,
courtship
Courtship is the period wherein some couples get to know each other prior to a possible marriage. Courtship traditionally may begin after a betrothal and may conclude with the celebration of marriage. A courtship may be an informal and private m ...
songs involve shorter notes to attract potential mates, and are followed by longer tones to repel males.
Frequency of sounds produced generally negatively correlates with body size both within and among species, and allows competing males to assess body size of vocalizing neighbouring
frog
A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-frog" ''Triadobatrachus'' is ...
s.
Male
frog
A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-frog" ''Triadobatrachus'' is ...
s typically approach higher frequency sounds more readily than lower frequencies, likely because the
frog
A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-frog" ''Triadobatrachus'' is ...
producing the sound is assessed to be a smaller, less dangerous competitor.
In territorial
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s, males increase song production rate when neighbouring males encroach on their territory.
In
great tit
The great tit (''Parus major'') is a passerine bird in the tit family Paridae. It is a widespread and common species throughout Europe, the Middle East, Central Asia and east across the Palearctic to the Amur River, south to parts of North Af ...
s (''
Parus major''),
nightingales (''
Luscinia megarhynchos''),
blackbirds (''
Turdus merula'') and
sparrows (family
Passeridae
Old World sparrows are a group of small passerine birds forming the family Passeridae. They are also known as true sparrows, a name also used for a particular genus of the family, '' Passer''. They are distinct from both the New World sparrows, ...
), playing song recordings slows the rate at which males establish territories in an unoccupied region, suggesting these
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s rely on song output in establishing territorial boundaries.
Experimentally muted
Scott's seaside sparrow (''
Ammodramus maritimus'') lose control of their territories to other males.
Thus, territorial
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s often rely on song production to repel conspecific males.
Individual recognition
Like the
human voice,
bird song typically contains sufficient individual variability to allow discrimination of individual vocal patterns by conspecifics. Such discrimination is important to mate recognition of many monogamous species.
Seabird
Seabirds (also known as marine birds) are birds that are adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same enviro ...
s, for example, often use vocalization patterns to recognize their mate upon reunion during the breeding season. In many colonial nesting birds, parent-offspring recognition is critical to allow parents to locate their own offspring upon return to nesting sites.
Cliff swallows (''
Petrochelidon pyrrhonota'') have been demonstrated to preferentially respond to parental songs at a young age, providing a means of vocalization-based offspring recognition.
Social transmission and learning
Learning and development of birdsong
Learned vocalizations have been identified in groups including
whale
Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and ...
s,
elephant
Elephants are the largest existing land animals. Three living species are currently recognised: the African bush elephant, the African forest elephant, and the Asian elephant. They are the only surviving members of the family Elephantidae ...
s,
seals, and
primate
Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians ( monkeys and apes, the latter including ...
s, however the most well-established examples of learned singing is in
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s. In many species, young
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s learn songs from adult males of the same species, typically fathers. This was first demonstrated in
chaffinches (''
Fringilla coelabs'').
Chaffinches raised in social isolation develop abnormal songs, however playing recordings of
chaffinch
The common chaffinch or simply the chaffinch (''Fringilla coelebs'') is a common and widespread small passerine bird in the finch family. The male is brightly coloured with a blue-grey cap and rust-red underparts. The female is more subdued in ...
songs allows the young
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s to learn their species-specific songs.
Song learning generally involves a sensitive learning period in early life, during which young
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s must be exposed to song from tutor animals in order to develop normal singing as adults.
Song learning occurs in two stages: the sensory phase and the sensorimotor phase. During the sensory phase,
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s memorize the song of a tutor animal, forming a template representation of the species-specific song.
The sensorimotor phase follows and may overlap with the sensory phase. During the sensorimotor phase, young
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s initially produce variable, rambling versions of adult song, called subsong.
As learning progresses, the subsong is replaced with a more refined version containing elements of adult song, called plastic song. Finally, the song learning crystallizes into adult song. For song learning to occur properly, young birds must be able to hear and refine their vocal productions, and birds deafened before the development of subsong do not learn to produce normal adult song.
The
sensitive period in which
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s must be exposed to song tutoring varies across species, but typically occurs within the first year of life.
Birds in which song learning is limited to the initial sensitive period are referred to as closed-ended learners, whereas some birds (e.g.
canaries; ''
Serinus canaria
The Atlantic canary (''Serinus canaria''), known worldwide simply as the wild canary and also called the island canary, common canary, or canary, is a small passerine bird belonging to the genus '' Serinus'' in the finch family, Fringillidae. I ...
''), continue to learn new songs later in life, and are called open-ended learners.
Some species of
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s, such as the
brown-headed cowbird
The brown-headed cowbird (''Molothrus ater'') is a small, obligate brood parasitic icterid native to temperate and subtropical North America. It is a permanent resident in the southern parts of its range; northern birds migrate to the southern ...
(''
Molothrus ater''), parasitize other
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
species, laying their eggs in the nests of other
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s such that the heterospecific bird raises the chicks.
Although most
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s acquire song learning within the first year,
brown-headed cowbird
The brown-headed cowbird (''Molothrus ater'') is a small, obligate brood parasitic icterid native to temperate and subtropical North America. It is a permanent resident in the southern parts of its range; northern birds migrate to the southern ...
s have a delayed
sensitive period, occurring approximately one year after hatching.
This may be an adaptation to prevent the young
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s from learning the songs from the foreign bird species. Instead, the young
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s have a year in which to find conspecifics, and learn their own species-specific song.
Bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s are generally predisposed to favour learning of conspecific songs, and will typically preferentially learn the song form conspecific animals rather than heterospecifics.
However, song learning is not completely restricted to within-species songs. If exposed to heterospecific
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s of another species in absence of same-species birds, young
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s will often adopt the song of the species to which it was exposed.
Although
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s are capable of learning song production purely from audio recordings of
birdsong
Bird vocalization includes both bird calls and bird songs. In non-technical use, bird songs are the bird sounds that are melodious to the human ear. In ornithology and birding, songs (relatively complex vocalizations) are distinguished by func ...
, tutor-student interaction may be important in some species. For example,
white-crowned sparrow
The white-crowned sparrow (''Zonotrichia leucophrys'') is a species of passerine bird native to North America. A medium-sized member of the New World sparrow family, this species is marked by a grey face and black and white streaking on the uppe ...
s (''
Zonotrichia leucophrys'') preferentially learn the songs of
song sparrow
The song sparrow (''Melospiza melodia'') is a medium-sized New World sparrow. Among the native sparrows in North America, it is easily one of the most abundant, variable and adaptable species.
Description
Adult song sparrows have brown upperp ...
s (''
Melospiza melodia'') when exposed to recordings of
white-crowned sparrow
The white-crowned sparrow (''Zonotrichia leucophrys'') is a species of passerine bird native to North America. A medium-sized member of the New World sparrow family, this species is marked by a grey face and black and white streaking on the uppe ...
s and live
song sparrow
The song sparrow (''Melospiza melodia'') is a medium-sized New World sparrow. Among the native sparrows in North America, it is easily one of the most abundant, variable and adaptable species.
Description
Adult song sparrows have brown upperp ...
s.
In other words, the interactive nature of a live tutor seems to trump the familiarity of the recordings from conspecifics.
Cultural transmission of whale song
While vertical transmission (parent-offspring) is a common element of song learning, horizontal transmission among animals of the same generation can also occur.
Male
humpback whale
The humpback whale (''Megaptera novaeangliae'') is a species of baleen whale. It is a rorqual (a member of the family Balaenopteridae) and is the only species in the genus ''Megaptera''. Adults range in length from and weigh up to . The hu ...
s produce various songs over their lifetime, which are learned from other males in the population. Males in a population conform to produce the same mating song, consisting of a highly stereotyped vocal display involved in mate attraction.
The
cultural transmission
Cultural learning is the way a group of people or animals within a society or culture tend to learn and pass on information. Learning styles are greatly influenced by how a culture socializes with its children and young people. Cross-cultural res ...
of these songs has been found to occur across great geographic distances over years, with one study noting song transmission across the western and central South Pacific Ocean populations over an 11-year period.
See also
*
Animal communication
*
Animal language
Animal languages are forms of non-human animal communication that show similarities to human language. Animals communicate through a variety of signs, such as sounds or movements. Signing among animals may be considered complex enough to be a for ...
*
Bird song
*
Vocal learning Vocal learning is the ability to modify acoustic and syntactic sounds, acquire new sounds via imitation, and produce vocalizations. "Vocalizations" in this case refers only to sounds generated by the vocal organ (mammalian larynx or avian syrinx) as ...
*
Whale song
Whales use a variety of sounds for communication and sensation. The mechanisms used to produce sound vary from one family of cetaceans to another. Marine mammals, including whales, dolphins, and porpoises, are much more dependent on sound than ...
References
External links
Listen to Nature400 examples of animal songs and calls
Cornell Animal Sound Library(over 300,000 audio recordings from various species of mammals, birds, amphibians, fish, arthropods and reptiles).
has more than 150,000 recordings of 10,000 species
International Bioacoustics Councilmany links to animal sound sites
{{Zoomusicology
Zoosemiotics
Song forms
Song
A song is a musical composition intended to be performed by the human voice. This is often done at distinct and fixed pitches (melodies) using patterns of sound and silence. Songs contain various forms, such as those including the repetit ...