A Thesis Presented to the Faculty of San Diego State University
In Partial Fulfillment of the Requirements for the Degree Master of Science
in Interdisciplinary Studies: Animal Behavior
Helena Fitch-Snyder
Spring 2000
TABLE OF CONTENTS
ACKNOWLEDGMENTS iii
LIST OF TABLES viii
LIST OF FIGURES ix
CHAPTER
I. INTRODUCTION 1
Research Objectives 1
Reproductive Studies as a Literature Review 4
II. MATERIALS AND METHODS 9
Subjects and Housing 9
Sampling Procedures 13
Behavior 13
Hormones 16
Studbook Data and Colony Records 18
Data Analysis 18
Behavior 18
Studbook Data and Colony Records 19
III. RESULTS 21
Social Behaviors Associated With Mating Physiology 21
Approach, Leave/Depart, and Lounge 21
Whistle 23
Male Behavior During Female Estrus 28
Individual Variation in Behavior During Estrus 28
Effects of Social Housing on Birth Rates 31
Annual Reproductive Cycles of Males and Females 33
Sexual Maturity in Males 36
IV. DISCUSSION 40
Social Behaviors Associated With Mating Physiology 40
Effects of Social Housing on Birth Rates 43
Annual Reproductive Cycles of Males and Females 44
Sexual Maturity in Males 48
Summary 49
REFERENCES 52
APPENDICES
A. PYGMY LORIS TAXONOMY 59
B. PYGMY LORIS GENITALIA 63
C. PYGMY LORIS ETHOGRAM 65
D. BEHAVIOR DATA SHEET DURING NON-ESTRUS 68
E. BEHAVIOR DATA SHEET DURING ESTRUS 70
ABSTRACT 72
INTRODUCTION
Pygmy lorises (Nycticebus pygmaeus) are small, nocturnal
prosimians from Southeast Asia that are found distributed in Vietnam,
Cambodia, and Laos. (See Figure 1 on the following page.) This species is
poorly protected in the wild [Ratajsczak, 1988], and it is one of the least
studied of all prosimians. Virtually nothing was known about lorises'
reproductive patterns until the first pairs were imported to North America
in 1987. Since this time, basic reproductive parameters for this species
have been described, and these patterns have been compared with those of
its close relative, the slow lords (Nycticebus coucang) [Fitch-Snyder &
Perez, 1989; Izard & Weisenseel, 1989; Weisenseel et al., 1998]. More
recently, steroid hormone profiles have been successfully used to identify
the female pygmy lords reproductive cycle [Jurke et al., 1997] and also to
monitor pregnancy and birth [Jurke et al., 1998]. However, there have been
no studies examining the testosterone patterns of males until this study
was initiated. This thesis is the first report on male testosterone
patterns and reproductive behavior of pygmy loris pairs.
Research Objectives
The primary purpose of this research was to document annual
variations of testosterone production in male pygmy lorises and to both
males and females. This thesis had four objectives:
1) Identify the social behaviors that are correlated with mating
physiology. The behavioral patterns that comprise estrus, courtship, and
mating have not been previously examined in this species. Many zoos and
holding sites do not have access to lab facilities for hormone analysis,
and they may not routinely evaluate female vulva condition to determine
estrous condition. Documentation of the behavioral signs of estrus will
help animal managers to better recognize fertile periods in this species
and alert them to possible pregnancies.
2) Evaluate social housing and its possible effects on behavior
and birth rates. Compared to social species, little is known about
reproduction and behavior of solitary primates. In captivity, lorises are
typically housed as pairs throughout the year, although they are believed
to be solitary in the wild. There is evidence that some solitary species
are chronically stressed by close social proximity to conspecifics
[Lindburg & Fitch-Snyder, 1994]. Since many lorises breed poorly in
captivity, a comparison of pairing conditions was evaluated with respect to
reproductive behavior and birth outcome.
3) Determine annual reproductive patterns for males and compare
with the reproductive cycles of females. Jurke and co-workers [1997 and
19981 have previously identified hormonal and physiological measurements of
reproduction in this colony of pygmy lords females. A more complete
examination of reproductive patterns in this species was accomplished in
this study by comparing annual patterns of testosterone levels in males
with estrogen patterns of females.
4) Assess the age when male pygmy lorises become sexually mature.
The age of male fertility has not previously been evaluated against
conclusive hormonal data. Pygmy lords males have been known to pursue and
attempt to mount estrous females when they are only six months of age and
are half the size of the female. This study investigated the hormonal
background that underlies adolescent development by determining fecal
testosterone profiles of young males. Knowledge of these profiles will
enable animal care managers to determine when males should be paired for
breeding and at what age youngsters should be separated from their mothers.
HOW TO OBTAIN:
To borrow this document, contact Joanne Brown (brown@primate.wisc.edu),
Head of Technical Services, Wisconsin Regional Primate Research Center
Library and Information Service, University of Wisconsin-Madison. Fax:
1-608-263-3512
URL: http://www.primate.wisc.edu/pin/review/reprodpatt.html
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June 28, 2001
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