SOCIAL ORGANIZATION AND BEHAVIOR
Photo: David Haring
Study of social behavior of the aye-aye is still in its preliminary stages and
much remains unexplained. Aye-ayes are predominantly found alone and
rarely interact with other aye-ayes outside of their mating period (Ancrenaz et
al. 1994; Sterling 1995). However, aye-ayes were observed to travel,
forage,
and communicate together in groups as large as four outside of the mating season
(Sterling 1995). Associations of this type have been observed between males
and females and between males, but never between two females (Sterling 1993b).
The meaning of this behavior is uncertain. Males have significantly larger
ranges than females and often overlap the ranges of other males and females. The
large male ranges may be explained as part of their reproductive strategy, as
female aye-ayes are in estrous at different times and even then only for a brief
period. As a result, the large male range may represent an adaptation to find
estrous females (Sterling 1993b). Female ranges do not overlap and may be
determined by resource availability (Sterling 1993b; Ancrenaz et al. 1994;
Sterling 1995). As a result, females interact rarely and when they do, their
interactions are aggressive (Sterling 1995). Age at
dispersal
is unknown (Sterling 1995).
Males have been observed interacting in the wild with one another more often
than they interact with females. In addition, wide variety is seen in the
nature of interactions between males ranging from
agonistic
to affiliative
behaviors. Contact between males can still be considered rare,
but it can be assumed that different relationships exist between different
aye-aye males based on their differing interactions with one another (Sterling
1995).
REPRODUCTION
The aye-aye mating system is best described as scramble competition
polygyny
(Kappeler 1997). Scramble competition polygyny is characterized by a lack of
territorial defense by males but intense competition for access to receptive
females (Barrows 2001). In the aye-aye mating system, when a female is in
estrus,
she will call repeatedly to attract males. Males, up to six in number, will
group around the female and agonistically interact with one another for access
to the female. Females are
polyandrous,
mating with more than one male in a single estrus (Sterling 1993a). In the
wild, when one male gains access to the female,
copulation
lasts about an hour (Sterling 1995). This lengthy copulation may be a
mate guarding
adaptation to prevent other males from accessing the female and attempting to
disrupt the copulation to mate with her themselves (Sterling 1995; Jolly 1998).
After copulation, the female will move away quickly and resume calling (Sterling
1993b). These female mating calls are characteristic of mating
behavior and are uttered only in a mating context (Sterling 1995). Female
estrus is externally visible in the female and is characterized by genital swelling
and color change (Sterling 1993b; Andriamasimanana 1994; Winn 1994a). Full
estrus lasts from around 3 to 9 days (Sterling 1993a; Winn 1994a). In the wild,
before and during mating activity, swollen genitalia and an increase in
scent-marking has been observed in both sexes (Sterling 1994c).
In captivity, copulations were significantly shorter, lasting often around two
minutes. The captive female solicitation posture consists of a female placing
herself sideways next to a male and turning her head towards him (Winn 1994a).
In captivity, other methods of solicitation include vocalizations and the female
running up to a male, touching faces and running away (Dubois & Izard 1990).
Copulation has been observed to take place suspended from a branch with the
female grasping the branch and the male grasping only the female. After
copulation, the male and female groom one another (Beattie et al. 1992; Winn 1994a).
In captivity, the average female reproductive cycle lasts 49.8 days (Winn 1994a).
Average
gestation
for the captive aye-aye is 164 days (5.4 mos) (Glander 1994).
Sperm plugs
are present in females who have recently copulated in captivity, preventing
other males from mating with that female (Haring et al 1994).
Although long assumed to breed strictly seasonally, it appears the aye-aye's
breeding season is not as discrete as that of other lemurs (Sterling 1994c; Winn
1994a). The species breeds throughout the year but this does not mean that an
individual aye-aye will necessarily breed throughout the year (Sterling 1993b;
1994). The female aye-aye will typically begin reproducing around an age of 3.5
years and males will start copulating, but not necessarily successfully, at 2.5
years of age (Winn 1994b; Ross 2003).
PARENTAL CARE
Almost all of what is known about aye-aye parental care and infant development
stems from several captive births and the subsequent study of the developing
infants. Successful breeding programs have been established at the Duke
University Primate Center and the Jersey Wildlife Preservation Trust in the
UK Channel Islands. The first captive aye-aye was born in 1992 (Carroll &
Haring 1994).
Photo: A.S. Clarke
Weights at birth for captive-born aye-ayes have varied between 90g (3.2 oz) and
140 g (4.9 oz) (Beattie et al. 1992; Glander 1994; Haring et al. 1994). Body
weight at birth is proportional to the weight of the mother in that the less
the mother weighs, the less the infant is expected to weigh (Glander 1994).
At birth the aye-aye's ears are limp but become erect by six weeks of age
(Feistner & Ashbourne 1994). Captive infant aye-ayes remain in their nest
box for at least a month after birth and may remain there for as long as 60
days (Beattie et al. 1992; Feistner & Ashbourne 1994; Haring et al. 1994;
Winn 1994b). Not until the 15th week of life does the infant aye-aye spend
a majority of its time outside the nest-box (Feistner & Ashbourne 1994). In
the wild during its first two months, an infant aye-aye remained at its sleeping
site with its mother, never straying further than 50 m (164.04 ft) from the nest
(Andriamasimanana 1994). Wild female aye-ayes will often "park" their infants
in the nest while they forage (Sterling & Feistner 2000). Captive aye-ayes
carry their infants in their mouths when they feel the infant is in danger and
must be moved, and also during infrequent nest changes (Feistner & Ashbourne 1994;
Haring et al 1994). Captive carrying behavior by the mother persists as late as
33 weeks into the life of an infant (Feistner & Ashbourne 1994).
From birth, an infant aye-aye is able to vocalize and emit an "eeep" or a
"creee" when it feels distress or pain, and it also uses these vocalizations to
maintain contact with its mother (Haring et al. 1994; Winn 1994). In captivity,
an infant aye-aye is completely reliant on its mother for food until around
three months of age, when it starts to eat solid foods for the first time
(Feistner & Ashbourne 1994; Haring et al. 1994; Winn 1994b).
Infant aye-ayes are seen to play with their parents and also spend time alone
starting between the ninth week and third month of life (Feistner &
Ashbourne 1994; Winn 1994a; 1994b). Play consists of locomotor activities
including jumping around, sudden chases, mock lunges, fast vertical jumps, and
running along branches, and investigatory activities such as tapping
(Feistner & Ashbourne 1994; Winn 1994a; 1994b). Starting at this age, an
infant aye-aye will pass long periods of time engaged in play (Petter 1977).
Also around three months of age, the captive infant begins jumping, a pattern
also observed in wild aye-ayes of around that age (Andriamasimanana 1994;
Feistner & Ashbourne 1994; Winn 1994b). One of the main activities of the
young captive aye-aye is investigatory tapping with the third digit; this activity occurs
only infrequently by adulthood (Feistner & Ashbourne 1994; Winn 1994b).
Two suckling postures have been observed in captivity including one with the
mother standing and another with the mother prone on her side (Winn 1989).
Complete weaning in one captive case occurred at 170 days with the mother
actively discouraging suckling in the preceding six-week period (Winn 1994b).
Full independence of an aye-aye from its mother appears to occur later than 18
months after birth, as in one captive case an infant was separated from its
mother at 18 months and stopped gaining weight (Haring 1994). It is likely
that full separation occurs somewhere around two years of age.
COMMUNICATION
Aye-ayes, while primarily a solitary species, communicate with one another
through vocalizations and scent-marks (Sterling 1995). Aye-ayes have a
somewhat limited repertoire of vocalizations when compared to other primates
that have been studied in the wild and captivity (Stanger & Macedonia 1994).
Affiliative, agonistic, mating, and distress calls have been identified in the
wild. In one study, when other aye-ayes were encountered, around 50% of
vocalizations were affiliative (Sterling 1995). Wild affiliative calls include
short and long "eeps" used as contact calls (Sterling 1995). Other recorded
contact calls include "creeees," which may be a mother-infant cohesion call
(Petter & Charles-Dominique 1979). This "creeee" is uttered when the
captive infant aye-aye is separated from its mother to express pain, distress,
or loss of contact with its mother (Winn 1994). The "ggnnoff" is an affiliative
call that is uttered when one individual follows another closer than 10 m (32.81
ft) away and often results in two individuals feeding or grooming with one
another (Andriamasimanana 1994). The successive "Ron-tsit" is used to indicate
alarm or danger (Petter 1977). Agonistic calls include short "Aacks," and soft
and loud long "Aacks." These types of vocalization are used among aye-ayes as
warnings and as a method to maintain distance (Sterling 1995). Vocal
communication between aye-aye females is infrequent and predominantly agonistic
(Sterling 1995). Whimpers are uttered during copulation, during fights over
food, and in encounters between males and females. Other vocalizations include
the "scream," "plea," "sneeze," "snort," "hai-hai," "groan," and "whirr"
(Sterling 1995).
Photo: David Haring
In captivity, "screams" and "pleas" were only uttered when attempting to escape
restraint (Stanger & Macedonia 1994). Aggression is communicated by hissing
like a cat and assuming an aggressive stance (Petter 1977). Hissing is also
observed when an aye-aye is disturbed while sleeping. Aye-ayes may hiss
loudly while slowly approaching a threat (Petter & Charles-Dominique 1979).
Infant aye-ayes use some unique vocalizations not seen in adults. Captive
infants will produce "screams", "pleas", and "sneezes" as in the adults, but
they will also "grunt" and "rasp." The "grunt" appears to represent agitation
and the "rasp" was only heard a single time (Stanger & Macedonia 1994).
Several types of
scent-marking
have been observed in the wild including anogenital rubbing, head and chest
rubbing and overmarking (Sterling 1995). In captivity, several types of
olfactory clues were observed, including buccal (cheek) marking in which the aye-aye's
cheek is rubbed on an object leaving some saliva as well as anogenital marking
in which the individual rubs its anogenital region on an object by crawling
along it. Further types of marking include urine marking in which the aye-aye
will drag its posterior along a surface and leave a trail of urine and chest
marking in which a male forcefully presses his sternum into an object (Winn
1994). Anogenital marking, buccal marking, and urine marking have also been
observed in the wild (Petter 1977; Ancrenaz et al. 1994). It is not entirely
clear however, whether or not the aye-aye possesses scent glands (Price &
Feistner 1994). Preliminary research also indicates that aye-ayes may be able
to discriminate between the individual scents of different ages and sexes of
conspecifics
(Price & Feistner 1994).
Another form of possible communication seen in both wild and
captivity is the physical marking of branches by females biting the
surface, leaving a mark potentially for other aye-ayes to see
(Petter 1977; Ancrenaz et al. 1994). In addition, occasionally when others of
the species are nearby, aye-ayes display a characteristic pacing behavior which
may convey some message (Sterling 1995).
Content last modified: July 27, 2007
Written by Kurt Gron. Reviewed by Eleanor Sterling.
Cite this page as:
Gron KJ. 2007 July 27. Primate Factsheets: Aye-aye (Daubentonia madagascariensis) Behavior . <http://pin.primate.wisc.edu/factsheets/entry/aye-aye/behav>. Accessed 2018 August 1.
