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Sever1985 m scthesissummary

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Porcupine Hystrix indica, General Biology, Sever 1985

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Sever1985 m scthesissummary

  1. 1. Tel—Aviv University George S. wise Faculty of Life Sciences Department of Zoology STUDIES ON THE BIOLOGY OF THE INDIAN CRESTED PORCUPINE (Hystrix indica) IN THE COASTAL PLAIN OF ISRAEL Thesis submitted towards M. Sc. degree of the Tel—Aviv University by Zvi Sever The research for this thesis has been carried out at the Department of Zoology of the Tel—Aviv University under the direction of Prof. H. Mendelssohn September 1985
  2. 2. Ternporal and spatial patterns of activity, as well as social and feeding behaviour were monitored in free ranging Indian Crested porcupines (Hystrix indica) in the coastal plain of Israel, using radio telemetry. Fourteen porcupines (youngsters, subadults and adults) equipped with collar transmitters were radio tracked on 138 full nights and 3% partial nights and were also directly observed once a week by starlight scopa, during April 1983 — December 1984. HOME RANGE AND SPZJXTIAL ACTIVITY Differences in spatial activity were found between pairs and single males. There were no single female in the raearch area. The activity of the pairs was restricted to definite home ranges. Two pairs fedmainly in orchards; their home ranges were smaller and the utilisation was more evenly distributed as compared to a pair that fed mainly in a natural habitat ((5.335 km2,0.487 kmz vs. 1.215 kmz). Single males had a very wide temporary home range until they found a female with which to form apairbond. Considerable overlaps of home ranges between single males and pairs as well as among the single males, indicate that a single male is not territorial. Pairs displayed a characteristic movement pattern. A pair leaves its den for a specific area, where it spends most of the night. It usually returns to that-same den at the end of the night. Single males act alone. On some nights they may have the same movement pattern as described for pairs, but on others they wander for long distances (up to 8 km per night), sometimes ending up in a different den or even hiding in dense thickets. The average walking distance per pair per night is shorter than that of a single male (1684 i 789 vs. 23m : 1784 m. ).
  3. 3. ‘Ihe pattern of habitat utilisation is different for pairs and for single male porcupines; _15airs utilise specific areas on different nights. Single males utilise certain areas (sub-home ranges) for certain periods. Part of the research population was active in the sub—urban regiors. The problems posed by the railway and the highways that cross these areas, were solved by the porcupines‘ use of the large drainage-pipes passing under the tra nsportation 1i nes. TEMPORAL ACTIVITY PATTERNS Porcupines leave their dens in the evening after waiting for some time (fl—45 min. ) at the entrance. The porcupines forage every night and their activity above ground is continuous. In spring and summer 7.8% of the exits were before complete darkness (sun 129 under the horizon), in summer and autumn 61.5% of the observed returns to the den occured beyond the darkness hours and with the beginning of dawn. There is a connection between the type of habitat used by the porcupines and their emergence time. Those living in natural habitat start their activity two hours earlier than porcupines living on agricultural crops, but they all end their activity at the same time. During winter the activity ended at about $2.15 A. M., while in summer it was terminated between 04.(2H2l to $5.69 A. M.. A single male might finish its activity very late even during the winter season. Duration of activity increased from winter to late summer. Adult animals (14.5 1 2.1 kg. ) are active per night, in winter and spring, for 6.3 i 1.6 hrs. in natural habitat and 4.3 i 1.0 hrs. in agricultural habitat. This average activity reprsents 50% or less of the darkness hours. In summer and autumn activity increased up to 7.4 1 0.9 hrs. and 5.2 1 1.3 hrs.
  4. 4. respectively to the habitats and represents 98% and 66% of the darkness hours. Rain inhibits above ground activity. There was no correlation of activity parameters with temperatures and humidity but it appears that a combination of high humidity and low temperature is the signal to enter the den in winter nights. I 7 During winter porcupines reduce their aboveground activity for minimal exposure to moonlight, but the lunar response wanes thereafter and disappears completely by summer. Moon avoidance may be a defence behaviour pattern against predators, that can be expressed during winter, but disappears during short summer nights, when there are not enough darkness hours to meet foraging requirements. Results suggat that porcupin$ accumulate foraging deficit for about 19 consecutive nights per winter lunar cycle, and compensate for it during moonlas nights. DENS During the day the porcupines usually hide underground, but sometimes in above ground shelters. Single males often use dense thickets as shelters during the day, while pairs usually hide in underground shelters. ‘Ihe burrows are used by the porcupines as places for spending inactive time and for reproductive purposes. As underground shelters porcupines use "artificial dens" (drainage—pipes along and under highways and under a cemetery, 450 to -690 meters long and 76 cm. in diameter) as well as self-dug dens. A natural den usually has an hemieliptic entrance (39 :6 cm. wide and 24 :4 cm. high), the den is long (8.7 i 5 m. ) and its diameter is in accordance with the porcupine's size. The den ends with a nest, providing a place for two adult porcupines (80x90x5(J cm. ). Food and faeces were not found inside the dens. In the sub—urban region porcupines prefer to use the drainage-pipe: as dens.
  5. 5. /' NUTRITION Ten species of geophytes were identified from the porcupines‘ digging activity. The density of the porcupines‘ diggings can be as high as one digging for every square meter of soil. ‘Ihe average size of a digging is 25x35x36 cm. Porcupines do not usually eat the above ground parts of thegeophyte. During autumn, winter and spring porcupines were observed eating buds and green grass on the ground. In agricultural areas porcupines fed on vegetables and fruit, including fruits growing on low branches, that could be reached by. the animals. REPRODUCTION AND DEVELOPMENT Data in this section includes information from the museum of Tel- Aviv University and from porcupines captured in the Judean mountains. Births occur throughout the year, but mostly during spring and autumn. The litter range is 1-3 and the average is 1.77 1 6.56 (N=3l). The average weight of neonates is 327 j-_ 27 gr (N=5). This represents 2.6% of the mean body weight of an adult female. Until the age of 4.5 months the body weight of the young increases with increasing age. From this age on the increase in body weight slows down and becomes very slow from the age of 11 months. From recapture of adult porcupines it was found that porcupines continue to gain weight throughout their lives. ‘Ihe birth of a neonate, born to a 12 months old female and a 16 months old male indicata that porcupines are able to copulate at the age of 9 and 7 months respectively.

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