Time and Space Sharing Between Platypuses (Ornithorhynchus anatinus) in Captivity.

Detailed video monitoring studies of the activity patterns of platypuses, Ornithorhynchus anatinus, given free access to a variable captive system were conducted. When alone, platypuses in captivity linked their activity to the nocturnal light cycle and followed a predictable pattern of activity. This was mostly confined to the dark photo-period and with long periods of continuous presence in the water. When individuals were paired a 'dominance' relationship usually developed. The adult male was dominant over the females in all combinations. In the pairing of a sub-adult male and female, the female remained dominant and between two females there was little indication of dominance. The dominant animal's pattern of activity in the water remained similar to that when kept alone, except for a slight lengthening of its active period and spread of activity. The second animal's active period shortened and became more fragmented. The spread of its activity increased and the activity moved more into the high light periods when the dominant animal was not present. All the activity criteria examined could reflect different strategies for the separation of the activity- cycles changes to the length of the active period, leaving the tank when the other animal was present, increasing the spread of activity, extending activity into the 'daylight' period. It was concluded that one reason behind the changes of activity pattern in paired platypuses was the desire for an un-interrupted feeding time.