them over the caterpillars before pouncing on them.

In the wild state, lion-tail groups average about 20 individuals, usually

with more than a single adult male present. Males are larger than females by

about a third and are typically ranked relative to one another in a social

hierarchy. Males usually emigrate from their natal group to join another

during the early stages of adulthood. Being macaques, lion-tails are

intensely social and are highly aggressive toward unfamiliar individuals.

Preliminary work on our captive population indicates that much of the

behavior between group members is dependent upon one's relationship to a

small number of female-headed lineages. It is possible to have up to four

living generations within each matriline and four or five matrilines within a

group. Dominance relationships among and within matrilines play a crucial

role in the everyday life of females and their offspring, as they do for

adult males. One's social position determines access to essential resources

such as food, perches, and social partners.

LION-TAILED MACAQUES: FUTURE PLANS

This highly endangered primate has been exhibited at the San Diego Zoo since

1923. In 1979, the existing population of three males and three females was

relocated to the Primate Research Pad for concentrated study of their

reproductive biology. Within the next decade their reproductive cycles were

characterized, as were their sexual and social behavior, parturition and

infant rearing, and various other aspects of the captive experience. Nearly a

dozen scientific papers from these studies have been published in peer-

reviewed journals or as book chapters.

BY 1989 the Zoo's captive population had grown to 38 individuals. This same

year the program undertook a significant change in direction. Seven

individuals, including five born at the Primate Research Pad, were released

into a state-of-the-art exhibit in Sun Bear Forest. Although these

individuals are no longer under study, it was knowledge gained over the

previous decade that contributed to the design of an exhibit facility which,

by anyone's criteria, is an outstanding success.

A second troop of 11 individuals was simultaneously relocated to the newly

constructed 3/4-acre breeding kraal at the Wild Animal Park. It is this

population which will be a major research focus during the next five years.

This troop has been exempted from Species Survival Plan management, a program

of the American Association of Zoological Parks and Aquariums, providing

freedom to pursue several interesting lines of inquiry. One of these has to

do with the impact of traditional management regimes on certain life history

parameters. The second investigation will pursue experiments designed to

prepare the troop for reintroduction to suitable habitat in India in five to

seven years.

The lion-tailed macaque is by nature a highly social mammal. Group members

are organized in a social hierarchy that appears to remain stable over many

years. Individual troops are highly xenophobic. This trait, combined with

natural aggressiveness, results in potentially fatal conflict when new

individuals are introduced. In the wild state, males will leave their natal

troop at sexual maturity and join a new one. Females remain in their natal

troops throughout their lives.

Transfer by males is accompanied by a substantial amount of aggression, but

is presumably a necessary event to preclude inbreeding. These natural

attributes of wild troops would seemingly have profound implications for the

transfer of individuals, especially of females, between zoological

institutions to satisfy genetic and reproductive objectives.

It is relevant to ask if the ongoing disturbance of the social order through

frequent inter-institutional transfers might negatively impact on such

parameters as infant mortality, female fecundity, and perhaps even the

neonatal sex ratio. Our kraal group has been together for the past 24 years,

the only social disturbances having been the replacement of breeding males.

We have learned how to integrate new males into groups with a minimum of

social upheaval. We therefore have a unique opportunity to compare findings

from our relatively undisturbed population with those from more traditionally

managed populations in other zoos over the next several years.

Preparation of this same troop for reintroduction to the wild has two

components. The first entails a number of experimental procedures designed to

"teach" natural foraging, avoidance of predators (including humans), and

appropriate social cohesiveness. In addition, the troop must be routinely

evaluated for any pathogens that would pose a hazard to the existing wild

population.

The second component is evaluation of potential release sites in the wild.

The area selected for a test-case reintroduction must not only be protected

from human activity, but must contain adequate food and shelter to insure the

long-term survival of the troop. CRES anticipates working closely with Indian

colleagues on this aspect.

NIGHTTIME IS THE NORM: LABOR AND BIRTH IN THE LION-TAILED MACAQUE

Lion-tailed macaque neonates (newborns) are born with black fur, and their

faces, hands, and feet are pink and hairless. Their characteristic silver

manes do not begin to grow in until the babies are several weeks old, and

their faces gradually acquire the black pigmentation of adults.

When the lion-tailed macaque breeding and management program began at the

CRES primate facility more than ten years ago, little was known about the

gestation, labor, and delivery of infants in this species. There was

extensive documentation of parturition in some other macaques, but no

comparable data were available on the much rarer lion-tailed macaque. How

long is the normal gestation length? At what time are births most likely to

occur? How long does labor last? What factors indicate that there may be a

delivery problem requiring veterinary intervention? Answers to these and

other important questions were needed in order to ensure the best captive

management procedures and to maximize the breeding success for this species.

The primary reason these data had not been collected previously is that most

new infants were usually discovered in the morning, after the keepers arrived

at work. We began collecting data on each lion-tailed macaque birth by

setting up 24-hour "birth watches" that began several days before the dam was

due to deliver. Conception dates were determined partially through hormone

data from daily urine samples, and also by keeping careful track of

menstruation, sex-skin swellings, and mating episodes. Parturition-date

predictions were based on the 168-day gestation length documented for the

rhesus macaque. However, because this is an average length, we began our

observations about ten days before the due date in order not to miss the

early deliveries.

The birth watch involved round-the-clock observations at 15-minute intervals

during successive, 4-hour shifts. Observations were recorded by keepers,

technicians, and trained volunteers. As soon as any signs of straining or

birth fluids were noted, continuous notes were kept and each subsequent

contraction or birth-related event was timed and recorded. Behavioral

indications of impending labor included restlessness and manual exploration

of the vaginal area. Although these signs eventually proved reliable, we used

the first, clear contraction as the starting point for measuring the duration

of labor. (In human terms, this is equivalent to second-stage labor. The

usual criterion of first-stage labor, cervical dilatation, cannot be observed

in the wild primate unless restraint is used.) During actual labor, several

straining postures were noted; most common were variations of squatting

postures and arched-back stretches.

The first birth was to an experienced mother (this was her third delivery)

and was documented on videotape. After nearly 8 full hours of labor and 188

contractions, the dam gave birth to a healthy, female infant. These initial

observations led us to believe that a labor of this duration was not a basis

for concern; however, we soon learned that this was far beyond the average

labor length and number of contractions common for this species.

Over an 8-year period, we were able to collect data on 18 births from 8

different mothers in our colony. Our program has provided some valuable

information about species-typical birth patterns that we can now use to

direct management decisions. We found that the average length of labor to

expulsion of the fetus was about 2 hours and 15 minutes, and the shortest

labor was only 50 minutes total. The female that required eight hours to

deliver in the first case observed then delivered her subsequent infant in

only a little over an hour! Although our sample is still small, it would

appear that, on the average, first-time mothers have longer and more

difficult labors.

Our study determined that the average number of contractions to delivery for

lion-tails was 54. The female with the longest labor also had the largest

number of contractions (454). In her next delivery, the infant arrived after

only 14 contractions, the lowest number recorded during the entire birth

study. Based on the average number of contractions seen in 17 successful

deliveries, and one ending in stillbirth, contraction frequencies approaching

75 to 100 in number may serve as a warning that intervention will be

necessary.

The average length of gestation for 14 pregnancies in our colony was 169.5

days, with a range of 163 to 176 days. This is very similar to what has been

reported for other macaques. Our observers quickly discovered that those who

watched during the 7 to 11 P.M. shifts were the most successful at being

present when births occurred: labor began between the hours of 7:15 P.M. and

3:15 A.M. in every case but one. The exception was one first-time mother that

began straining in the early afternoon. This female had a difficult labor,

and a dead fetus was later removed by cesarean section after 8 hours of

straining and 193 contractions. All the other births resulted in live

offspring and occurred between the hours of 8:05 P.M. and 6:28 A.M. Based on

previous primate birth records, daytime births are not the norm and may

indicate an increased risk to both fetus and dam.

Expulsion of the placenta always took place within about 20 minutes after

parturition, and usually it was immediately consumed by the mother. In a few

cases, first-time mothers carried the placenta around for several hours,

along with the infant, until it could be removed by keepers. Whenever

possible, a sample of the placenta is saved for analysis by Zoo pathologists,

who check it for abnormalities. After delivery, the mothers carefully lick

the birth fluids off their infants, and the neonates begin nursing within a

few hours. Each and every female in the study provided excellent maternal

care immediately following parturition.

The lion-tailed macaque breeding colonies are now located in the Sun Bear

Forest exhibit at the Zoo (one adult male and six females) and in a large,

off-exhibit kraal at the Wild Animal Park (one adult male, two juvenile

males, one infant male, and ten females). Together these represent the

largest captive group of lion-tailed macaques in the world -- about 20

percent of the total captive population. Eight years of patient monitoring,

birth watches, record keeping, and evaluation have brought us a long way in

the breeding and captive management of this macaque species.

ZOONOOZ, May, 1990 "Nighttime Is the Norm: Labor and Birth in the Lion-tailed

Macaque," by Helena Fitch-Snyder, Animal Behavior Specialist/CRES and Donald

Lindburg, Ph.D. Behaviorist/CRES.

MORE ON IGUANAS

The environment in which a lizard lives may determine how easily its scent

marks can be located by other lizards. Both desert iguanas (Dipsosaurus

dorsalis )and green iguanas (Iguana iguana) possess femoral glands on the

underside of the hind legs. They use pheromone secretions from these glands

to mark their territories. Desert iguanas live in extremely hot and arid

habitats, whereas green iguanas live in humid tropical forests. Because these

two species of lizards live under such different environmental conditions, it

is not surprising that the way their pheromone signals are transmitted

differs.

Desert iguanas have scent marks that are nonvolatile, which means that they

evaporate very slowly into the atmosphere. These marks are also extremely

resistant to chemical breakdown at high temperatures. The low volatility and

thermal stability of desert iguana scent marks ensures that they persist

under harsh desert conditions, a necessary quality if they are to be used

effectively for territory marking. Although these characteristics make scent

marks more durable in desert environments, they pose a problem for desert

iguanas attempting to detect them if the marks are not volatile; they may be

difficult or impossible to locate using smell. Desert iguanas avoid this

problem by combining a unique type of visual signal with their scent marks.

One striking property of desert iguana scent marks is that they strongly

absorb ultraviolet light. Although these wavelengths are invisible to human

eyes, they appear dark to animals able to see ultraviolet light -- much as

ultraviolet-absorbing honey guides on flowers look black when UV-sensitive

camera film is used to view them. Recent studies have shown that desert

iguanas are able to see long-wave ultraviolet light, and they may use this

adaptation to detect scent marks from a distance. After scent marks are

localized using visual cues, desert iguanas can approach and investigate them

in more detail through tongue-flicking. Although it is not known to occur in

mammals, visual sensitivity to ultraviolet light has been shown in certain

insects, spiders, fish, frogs, and birds. The ability of desert iguanas to

detect ultraviolet light may help them solve some of the problems associated

with finding scent marks in a desert environment.

In contrast to those of desert iguanas, the scent marks of green iguanas

contain a variety of volatile chemical compounds, and they do not absorb

ultraviolet light. Behavioral studies indicate that green iguanas, unlike

desert iguanas, can detect these scent marks by smell alone. Because the

chemical components of green iguana scent marks remain active and transmit

well under the humid conditions of tropical forests, green iguanas do not

appear to need a visual cue in order to locate scent marks. Research on both

iguana species demonstrates how the environment in which animals live can

influence the nature of the communication signals they employ.

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