. The biology of marine animals. Marine animals; Physiology, Comparative. 460 THE BIOLOGY OF MARINE ANIMALS It is in these animals, again, that modifiability of response and learning reach greatest development. The behaviour of shore crabs, notably Uca, reveals various interesting social features, such as defence of territory, visual and auditory signalling. Carcinus maenas, when tested in a simple maze, shows some ability to improve with practice. Experiments with other crabs—hermit crabs, fiddler crabs—have involved reversal of some proclivity. Fiddler crabs, for example, learn to reverse th
. The biology of marine animals. Marine animals; Physiology, Comparative. 460 THE BIOLOGY OF MARINE ANIMALS It is in these animals, again, that modifiability of response and learning reach greatest development. The behaviour of shore crabs, notably Uca, reveals various interesting social features, such as defence of territory, visual and auditory signalling. Carcinus maenas, when tested in a simple maze, shows some ability to improve with practice. Experiments with other crabs—hermit crabs, fiddler crabs—have involved reversal of some proclivity. Fiddler crabs, for example, learn to reverse the direction they normally take in escaping from a particular situation. Good performances have been secured after some thirty to fifty trials in some animals (99). The octopus has proved to be a most rewarding animal for experimental studies of learning, and an attempt has been made to correlate certain aspects of its behaviour with central nervous organization. Octopuses Shock 0. T T T T 6 Days 8 10 12 Fig. Progress of Learning in the Octopus In the experiments the octopus was fed with crabs, and in some trials a white square was presented with the crab. Whenever the octopus attacked the crab + white square, it was given an electrical shock. After 2-5 days of training, the octopus learnt to dis- tinguish between the two stimulus-situations (crab alone, hollow circle, and crab + square, solid circle), to leave the crab alone when the white square appeared. The graphs show the ratio of number of attacks to trials during the course of experimentation (abscissae in days). (From Boycott and Young, (13).) inhabit niches from which they venture forth to attack prey of suitable character and size. In an aquarium they attack living crabs which they recognize by sight. By presenting a crab in various situations, it has been possible to analyse certain aspects of octopus behaviour. When an octopus is shown a crab together with a white signal square, and it is given an ele
Size: 2192px × 1140px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, booksubjectmarineanimals, booksubjectphysiology
