PSY352H5 Lecture Notes - Lecture 7: Entwine, Coevolution, Animal Communication
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Lecture 7
Perhaps all species of animals use some form of communication
• Bees dance when they have found nectar.
o The dance conveys information about where the pollinated flowers are, how far they are,
how much effort the bee has to make to get to the flower
o If there is head wind it will make the bee think its further, if there is tail wind, then it
thinks it closer
o Also tells direction
• Chimpanzees greet each other by touching hands.
• Male fiddler crabs wave their giant claw to attract female fiddler crabs.
• White-tailed deer show alarm by flicking up their tails.
• Dogs stretch their front legs out in front of them and lower their bodies when they want to play.
o Some argue that dogs have co-evolved with humans so that they are particularly sensitive
to human calls
• Elephants show affection by entwining their trunks.
o Elephants use movements and sounds
• Giraffes press their necks together when they are attracted to each other.
• Gorillas stick out their tongues to show anger. Kangaroos thump their hind legs to warn others of
danger.
• Prairie dogs bare their teeth and press their mouths together to discover if they are friends or foes.
• Whales breach (leap out of the water) repeatedly to send messages to other whales.
o They can communicate through long distances
• Swans entwine their long necks both to fight and to court. Horses rub noses as a sign of affection.
• Kangaroo rats stamp their feet drumming for territory, drumming for a mate, or drumming to
warn off snakes.
• And the list goes on.
• Depending on the species the signals can come from different modalities
• Fish can use electric signals as well as lateral lines
o Lateral lines are wholes in the scales that detect signals (tactile signals)
Across different species all modalities are used for communication
• Visual
• Auditory
• Olfactory
• Tactile
• Electrical
Communication in the African elephant: beyond our perceptual abilities
• The most common elephant vocalizations, called “rumbles”, are so low in pitch that they are
difficult for humans to hear.
• Elephant 'friends' exchange rumbles when they are out of contact, during reunions, and when
approached by dominant animals.
• Additionally, each female has a distinctive sounding rumble, and elephant rumbles become shaky
when dominant animals are nearby.
• These findings suggest that elephants can recognize each other by their voice alone, and that
emotion is expressed in elephant voices.
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Communication is the transmission of information from one animal to another in a manner beneficial for
the signaling animal
• Intentional transmission
o Means that the animal meant to create the signal and by doing so it is beneficial for the
signalers
o The animal expects the signal to be received by another animal, doesn’t mean that it is
consciously aware
• The intentional aspect is a bit controversial
• “Intentional” doesn’t necessarily mean consciously aware
• “Intentional” just means that the purpose of transmission was communication
• “Intentional” can be in terms of evolutionary or adaptive sense (why does a peacock spread its tail
feathers?)
Intended vs. unintended receiver the “purpose” of the signal
• The point about “intention” is whether the communication signal was meant for the receiver or
not
• The intention of the alarm call to alert other prey about the presence of the predators
o But some predators have evolved to recognize these calls
• A predator may hear the alarm call and locate the transmitting animal based on the auditory
stimulus.
• The ant eater snake may find the ants based on the pheromone trail they have left behind.
• A predator may detect the male stickleback because of his red belly.
• But these signals were not meant for the predator.
• Communication should involve the transmitter individual and the receiver individual for whom
the signal was meant.
• Even in the case of humans, intention is not always presence when making decision
The peacock displays to attract females
• The peacock is not really aware of the purpose of his own behaviour but he “feels like” doing it
when he sees a female (trick of evolution).
• The purpose of this communication is to advertise status and health
Red belly in sticklebacks advertising: I’m a dominant male ready to spawn with you and ready to defend
my home for you
• The red belly signals this
• It is communicative signal that delivers this message
• It is not a conscious signal, the fish doesn’t know that their belly is red
By the way sports car ads often show the car in red: human males, speed, power, and dominance status?
• Most people pick sport cars in bright colours or make modifications to it to make others see it
more
Courtship in sticklebacks: stereotypical movements, important species specific communication
• These communicative signals are species specific and practically unmodifiable
o Because it is important for reproduction and those that cannot communicate well will not
be able to pass their genes to the next generation
o Thus communication is especially important in reproductive period
• Reproduction is the key to evolutionary success
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o Strong selection for proper communication and interaction between members of the
opposite sex
Aerial acrobatics of eagles: which mate is the fittest?
• The birds fly high and the male drops a rock and the other one catches it
• They do this to test the mate and their ability to hunt, fly fast and catch the rock
• It is a good way of judging fitness even though they don’t know the results of this
• Their brain tells them to do and they just like to do it
• Humans also have this period of courtship where they are testing the quality of the genome of the
potential mate
Bird song, dance, and evaluation of the partner
o Pair bonding species have to be very selective as to who they choose.
o Large investment: “quality” of offspring will depend on quality of mate.
o Crucial need for proper evaluation of the prospective mate
Red-winged blackbirds: Dominant males sing louder, longer, and more elaborate songs\
• The quality and strength of the song determines health of the male bird which then the women
choose
Bird song and hormonal status
o Castration reduces singing
o Androgenic and estrogenic metabolites given together, or testosterone given alone (an androgenic
hormone which can be converted to estogenic metabolites) to castrated males restored singing
Bird song and gene expression
• There are particular song producing nuclei in genes
• Singing in the context of territorial defense is associated with gene regulation in brain centers that
control song perception and production
• E.g. differentially increased expression of the transcriptional regulator ZENK in auditory
structures & song control nuclei of sparrows.
The bird song system is well mapped
• Particular brain areas are connected in order to produce song production
Female satin bowerbirds evaluate the fitness of potential mates on the basis of their energetic dances
• Based on dance movements of males
Song and Dance: Human reproductive behaviours
• People who dance better are seen as more attractive
• May be an indicator health
• Biologists working in Jamaica have shown that among humans, too, better dancers are rated as
more attractive and are preferred as mates.
• Singing and dancing have important neurophysiological effects on humans (endorphins &
dopaminergic system).
Communication is dependent upon the environment: Natural selection
• Atelopus zeteki: The Panamanian golden frog waves instead of croaking. It lives near fast moving
streams where background noise is high
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Document Summary
Perhaps all species of animals use some form of communication: bees dance when they have found nectar. Lecture 7: the dance conveys information about where the pollinated flowers are, how far they are, how much effort the bee has to make to get to the flower. Across different species all modalities are used for communication: visual, auditory, olfactory, tactile, electrical. Communication is the transmission of information from one animal to another in a manner beneficial for the signaling animal. Intentional just means that the purpose of transmission was communication. Intentional can be in terms of evolutionary or adaptive sense (why does a peacock spread its tail feathers?) Red belly in sticklebacks advertising: i"m a dominant male ready to spawn with you and ready to defend my home for you: the red belly signals this. It is communicative signal that delivers this message. It is not a conscious signal, the fish doesn"t know that their belly is red.
