Animal Communication ,competitions and interactions

Animal Communication ,competitions and interactions

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  COMMUNICATION IN ANIMALS
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  INTRODUCTION  Animal communicationis the passage of information b/w two animals.  The animal which sends is called signaller and the animal that recieves signal is called reciever.  Animal communication is also known as Biological communication.  The study of animal communication is called Zoosemiotics  The classical ethological view of communication was developed by Niko Tinbergen. Niko Tinbergen
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  TYPES OF COMMUNICATION Intraspecific communication ◦ communication within a single species  Eg. Honeybee dance  Interspecific communication ◦ Prey to predator  Eg. warning coloration in wasps ◦ Predator to prey  Some predators communicate to prey make them easier to catch, in effect deceiving them.  Eg. Angler fish ◦ Human/animal communication  During domestication of animals
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  BASIC COMPONENTS  Signaller: An individual which emits signal.  Reciever : An individual which recieves signal  Signal : The behaviour emitted by the signaller  Channels : A pathway through which normally a signal travels. (ie means of communication)  Visual  Auditory  Chemical  Tactile  Electrical  Suface vibration
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  VISUAL COMMUNICATION  Informationtransmitted by visual means is called visual communication.  The visual signals may be given by various means like ◦ movement ◦ posture or shape of the body ◦ Facial expressions. ◦ colour identification ◦ light etc.  Visual signals are used most often by species that are active during day.  Light as a visual means is used in night.
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  EXAMPLES 1) Visual communicationin Bees  The worker bees communicate about food mainly by a dance language.  It was decoded by Karl von Frisch in 1965.  Bees mainly perform 2 types of dances. ◦ Round dance - If source of nectar is less than about 100m away. Does not communicate the direction. ◦ Waggle dance – If source of nectar more than 100m away from hive. Communicates both distance and direction.
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   Round dance ◦Runs around in narrow circles, suddenly reversing direction to her original course. ◦ After the round dance has ended, she often distributes food to the bees following her. ◦ Essentially says "there is food closeby, get out and find the food, which smells like this.”
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   Waggle dance ◦Runs straight ahead for a short distance, returns in a semicircle to the starting point, runs again through the straight course, then makes a semicircle in the opposite direction to complete a full, figure-eight circuit. ◦ While running the straight-line course of the dance, the bee wags abdomen, vigorously sideways. ◦ The angle that the bee adopts, relative to vertical represents the angle in which food is found.
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  2) Postures  Somemammal species give specific signals by the position adopted by head, ears & tail.  Eg. Flattened ear – fear/ suspicion  Wagging of tail – Complete submission.  Retraction of lips to display teeth - threat display.
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  3) Facial expressions
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  4) Colours andDisplays  During mating season the male goldfinch has a bright yellow body  The gila monster's bright orange colored splotches are a warning to predators that it is poisonous and they should back-off.  When an animal exhibits a behavior that can be seen by other animals, it is called a display.  Male fiddler crabs wave their giant claw to attract female fiddler crabs.  Male peacock exhibits a visual display as part of its courtship rituals.
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  5) Light (Bioluminescence) Certain insects and deep sea fishes communicate via their light signals.  Luminuous insects are glow worms and their relatives the fireflies.  Eg. of light producing fish includes Anglerfishes Glow worms Fireflies. Anglerfishes
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  AUDITORY COMMUNICATION  Sendinginformation from one member to another by sound production is called auditory signal or bioacoustic signal.  Sound is a good means of communicating over long distances both in air and water.  It may have a vocal origin or it may be produced by some other organs  For eg. Calls of mammals and birds – vocal origin ; sound produced by crickets is rhythmic oscillation of forewings.  Sound is more effective signal at night and darkness  It can go around obstacles that would interfere with visual signals.  It is better than visual signals in getting attention of a reciever.
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  EXAMPLES  Deathwatch beetlesignal to each other by producing clicking sound made by tapping their head against wood.  Red squirrels will make a series of loud rattles and screeches to warn off intruders.  The bottlenose dolphin has a wide range of vocalizations. Each dolphin also has its own unique whistling sound that it uses to identify itself.  Male birds sing a song during breeding season. Deathwatch beetle Red squirrels Bottlenose dolphin
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  ODOUR OR CHEMICAL COMMUNICATION Molecules used for chemical communication between individual animals are called pheromones.  Pheromones are involved in mate identification, marking territory, alarm spreading etc.  Odour signals can transmit informations in dark, can travel long distances, can last for hours or number of days.  Usually the message causes an immediate response.  Chemical messages that pass between animals of the same species.  Chemical communication is the most primitive type of communication.
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  EXAMPLES  Female silkwormattract males by releasing a pheromone bombykol.  Queen honeybee attract males by 9 – oxodecenoic acid.  Alarm pheromones are produced in ants in the form of formic acid to protect themselves from enemies.  Ants lay down an initial trail of pheromones as they return to the nest with food.  A female gypsy moth may influence male moths few kilometres away by producing a pheromone called "disparlure".  Dogs and some other animals of dog family use urine to mark the boundaries of their territories.
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  TACTILE COMMUNICATION  Informationtransmitted in the form of physical contact (touch signal) is called tactile communication.  Antennae of ants, termites and honeybees are involved in this process  Eg. 1) Female primates often hold and frequently cuddle their young. Helps in establishing a bond 2) Termites – blind workers totally depend on his phenomenon. Two worker ants in tactile communication
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  ELECTRICAL SIGNALS  Itis a means of communication in some fishes.  Torpedo (Electric ray), and sharks (Scyliorhinus caniculus) have electro receptors that they use in communication.  Sharks detect the electric field produced by prey flatfish that are buried in the sand by a specialized organ called the ampulla of lorenzini.  Electric fish communicate information about species identity and sex by discharging electric field.
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  SURFACE VIBRATIONS  Insome animals information may be communicated by patterns of surface vibrations.  Eg. Water spider send out ripples of certain frequency and receptive female respond by moving towards the source.  Cannibalistic male spiders vibrate threads of web of his prospective partner communicating that it is not a prey.
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  FUNCTIONS OF COMMUNICATION Agonistic interaction – threat displays during competition over food, mates or territory  Mating rituals – to attract and maintain the attention of potential mate  Ownership/territorality – to claim or defend territory  Food-related signals – to lead members of a social group to a food source  Alarm calls – to warn of a threat from a predator
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  RECENT TRENDS  Dr.Jayne Yack of Carlton University in Ottawa, found that the walnut sphinx caterpillar has a special way of communication with its predators.  Make a squeaking sound that fends off attacking birds like Warblers .  Sound is made by blowing air out of two holes found in the abdominal spiracles.  It was found that they are mimicking the alarm call of another predatory bird. Communication in walnut sphinx caterpillar (Journal of experimental biology, Jan issue, 2012)
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  CONCLUSION  Animals docommunicate which involves information transfer from the sender to a receiver.  They can convey their needs, desires and reactions to the environment via some sophisticated signaling of their own.  No animals have however evolved the sophistication of the human language - communication system.  The understanding of animal communication is essential for understanding the animal world in general.