Diurnal and ultradian rhythms of behaviour in a mare group of Przewalski horse (Equus ferus przewalskii), measured through one year under semi-reserve conditions

Abstract Investigations were conducted on four horses from a group of 12 Przewalski mares raised in different zoos and kept in a 44-ha enclosure under semi-natural conditions. Activity and feeding were continuously measured every second and were saved every 15 min by the storage-telemetry system ETHOSYS, from June 1995 to July 1996. Body mass of the horses was regularly recorded. Daily and monthly mean values, power spectra and DFC (as a measure for stability of rhythms synchronised with circadiurnal period) for activity and feeding were calculated. The general pattern of activity and feeding over the year was closely related to sunrise and sunset. Feeding accounted for 40% of total activity in summer and 62% in spring (all-year average being 52%). The level of activity was lowest in winter; whereas feeding was lowest in summer. The time budget for feeding reflected both feeding conditions and the annual pattern of body condition. Greatest activity occurred during daylight hours. Only on hot summer days, activity at night was higher than during daylight hours. Spectral analysis of activity and feeding in Przewalski horse showed a time pattern which was characterised by 24-h rhythmicity, but also by ultradian components with period lengths between 4.8 and 12 h, i.e., an activity pattern of up to five strong bouts per day. Annual variation in the pattern of power spectra was not high during the year. Results are discussed in connection with horse feeding strategy. Analysing the time structure of long-term and continuously measured activity and feeding could be a useful method to follow the general living conditions, especially the nutritional situation and to detect stressful conditions.

[1]  P. Duncan.  Time-Budgets of Camargue Horses Iii. Environmental Influences , 1985 .

[2]  Y. Kaseda.  Seasonal Changes in Time Spent Grazing and Resting of Misaki Horses , 1983 .

[3]  D. Rubenstein.  Behavioural ecology of island feral horses , 1981 .

[4]  P. V. Soest,et al.  Digestive strategies and limitations of ruminants. , 1994 .

[5]  Jan Langbein,et al.  ETHOSYS (R)—new system for recording and analysis of behaviour of free-ranging domestic animals and wildlife , 1998 .

[6]  J Gill,et al.  A new method for continuous recording of motor activity in horses. , 1991, Comparative biochemistry and physiology. A, Comparative physiology.

[7]  Ronald R. Keiper,et al.  Nocturnal Activity Patterns of Feral Ponies , 1980 .

[8]  T. Jezierski,et al.  Observations of the twenty four hours rhythm of natural behaviour of Polish primitive horse bred for conservation of genetic resources in a forest reserve , 1978 .

[9]  J. Langbein,et al.  Comparative Analysis of Ultradian and Circadian Behavioural Rhythms for Diagnosis of Biorhythmic State of Animals , 1999 .

[10]  S. Daan,et al.  Phase Control of Ultradian Feeding Rhythms in the Common Vole ( Microtus arvalis): The Roles of Light and the Circadian System , 1993, Journal of biological rhythms.

[11]  G. W. Arnold.  Comparison of the time budgets and circadian patterns of maintenance activities in sheep, cattle and horses grouped together , 1984 .

[12]  M. Hutchins,et al.  Strategic collection planning: Theory and practice , 1995 .

[13]  P. Duncan,et al.  Temporal Patterns of Feeding Behaviour in Free-Ranging Horses , 1986 .

[14]  R. Brooks,et al.  Social organization of confined male collared lemmings (Dicrostonyx groenlandicus Traill) , 1978, Animal Behaviour.

[15]  P. R. Wiepkema.  Boekbespreking: Verhalten landwirtschaftlicher Nutstiere, H. Bogner und A. Grandvogl (Hrgbs). , 1985 .

[16]  A. Fraser.  The behaviour of the horse. , 1992 .

[17]  M. Dierendonck,et al.  Behavioural observations of reintroduced Takhi or Przewalski horses (Equus ferus przewalskii) in Mongolia , 1996 .

[18]  S. Beissinger,et al.  Limitations of Captive Breeding in Endangered Species Recovery , 1996 .

[19]  K. Houpt,et al.  The 24-Hour Time Budget of Przewalski Horses , 1988 .