Aye-aye (Daubentonia madagascariensis)


The mean female body mass is 2.572 kilograms and for the male the mean body mass is 2.617 kilograms (Feistner and Sterling, 1995). This species does not exhibit sexual dimorphism (Feistner and Sterling, 1995). The aye-aye is the largest nocturnal primate (Simons and Meyers, 2001). The dental formula of the adult aye-aye is 1:0:0:3 on the upper jaw and 1:0:1:3 for the lower jaw (Iwano, 1991a; Ankel-Simons, 2000). The milk teeth dental formula is 2:1:2 on the upper jaw and 2:0:2 on the lower jaw (Petter, 1977). There is a large diastema, gap, between the incisors and molars of the lower jaw (Ankel-Simons, 2000). The incisors of this species are always growing, like that found in rodents (Order, Rodentia). The head of this species is described as being short and large, and the neck is described as short but powerful (Petter, 1977). The eyes of the aye-aye are prominent and oriented toward the front (Petter, 1977). The aye-aye has areas of the brain that are larger than other prosimians: the pons-ventral area, cerebral hemispheres, and the cerebellum (Sterling and Povinelli, 1999). The large areas of the brain may have evolved to support the specialized foraging techniques of this species (Sterling and Povinelli, 1999). Aye-ayes have the largest encephalization index and the largest neocortical progression index amongst the prosimians (Stephan, 1972; cited in Milliken et al., 1991). Females have only one pair of inguinal mammary glands (Petter, 1977). The male has a penis that is described as being pendulous and terminates in a glans protected by a prepuce (Winn, 1994a). The male penis also has a baculum (Winn, 1994a). The scrotum is naked with glandular skin (Tattersall, 1982). This species has claws instead of nails on all of the digits except the hallux (Simons and Meyers, 2001; Petter, 1977; Iwano, 1991a). The hallux, or thumb, is opposable (Petter, 1977). The third digit on the hands is elongated, and is used to extract grubs from tree branches. The soles of the feet are covered with warts without crests (Petter, 1977). The aye-aye has a large tail that is slightly longer than the body (Petter, 1977).

The pelage of the adult is mostly black or dark brown (Petter, 1977; Tattersall, 1982). The face and the ventral side are slightly whitish in coloration (Petter, 1977; Tattersall, 1982). The limbs and the tail of the aye-aye are blackish brown in coloration (Tattersall, 1982). The long body hairs of this species lighten at the extremities (Petter, 1977). Infants are born with eyes that are green in color until 9 weeks when they change to light brown, and then at 15 weeks they are the sandy brown color of adults (Feistner and Ashbourne, 1994). The ears of the infant are floppy until about the fifth week when they become more erect (Feistner and Ashbourne, 1994). The hair on the face and shoulders is paler than that of an adult (Feistner and Ashbourne, 1994; Andriamasimanana, 1994). Winn (1994b) found that the infant pelage on the face and the belly were a white color. On the body of the infant there is two different layers of hair, one close to the body being dark and gray and long white guard hairs above this layer (Winn, 1994b). The top of the head, back, limbs, and tail of the infant has darker colored hair than the rest of the body (Winn, 1994b).

This species is found on the island of Madagascar along the eastern coast (Tattersall, 1982). The aye-aye occurs from Ankarana and Montagne d'Ambre in the North to Andohahela in the South (Sterling, 1998). Populations have been found in the West at Manongarivo and Tsingy de Bemaraha (Sterling, 1998). This species lives in primary forests, secondary forests, spiny desert, riverine forests, evergreen wet forests and dry deciduous forests (Rowe, 1996; Garbutt, 1999; Ganzhorn et al., 1999). The aye-aye can live in disturbed areas such as agricultural areas (Albignac, 1987).

The aye-aye is found in the following protected areas in Madagascar:

This species primarily eats insects and their larvae, but also will eat fruit such as mangos, eggs, and tree sap (Petter, 1977). A common larvae foraged upon is coleopterans of the family cerambycid (Erickson, 1994). Larvae of elaterid beetles are also commonly consumed (Erickson, 1994). Species of trees that insect larvae are extracted from include Anthocleista madagascariensis, Anthocleista amplexicaulis, and Rhus tarantana (Erickson, 1994). Bamboo shoots from Bambusa vulgaris have been found to be consumed by the aye-aye (Pollock et al., 1985). The fruit from Ficus spp. has also been observed to be consumed by the aye-aye (Andriamasimanana, 1994). The aye-aye was found to forage on cultivated plants such as coconuts, mangos, bananas, avocados, breadfruit and sugar cane (Albignac, 1987; Simons and Meyers, 2001; Petter and Petter, 1967; Petter, 1977; Andriamasimanana, 1994). Only the ripe part of mangos is consumed (Petter, 1977). This species will forage on fruit from Terminalia for the insect larvae that resides inside them (Petter and Petter, 1967; Petter, 1977). During the winter, the flowers from the traveller's tree, Ravenala madagascariensis, become an important food source (Ancrenaz et al., 1994).

On the island of Nosy Mangabe, the most important food sources are the drupaceous fruit of Canarium madagascariensis (Burseraceae), insect larvae, a cankerous growth on the bark of Intsia bijuga, and nectar from Ravenala madagascariensis (Sterling et al., 1994; Sterling, 1994a; Sterling, 1993; Pollock et al., 1985). On Nosy Mangabe this species also fed on the seeds of Terminalia catappa, a fungus growing on the stems of Macaranga cuspidata, and on adult ants (Sterling, 1994a). Seeds are eating by gnawing on the endocarp with the anterior teeth then extracting the cotyledons out with the third digit (Sterling, 1994a). The cankerous growth is either a fungus or a gall, and the Malagasy word for the growth is 'rikohintsina' (Sterling, 1994a). When feeding on the cankers of I. bijuga, this species will scrape away and consume the waxy substance from the underlying cambium (Sterling, 1994a). Pollock et al. (1985) suggest that elaterid larvae are the prime reason for aye-ayes to forage upon the galls. The nectar from R. madagascariensis is fed on by using the third digit to scoop the liquid out of the flower (Sterling, 1994a). Aye-ayes will extract insect larvae from dead trees and lianas than from any other sources (Sterling, 1994a). Canarium fruit are fed upon less during the cold, wet season, the growths on the bark of Intsia bijuga and foraged on more frequently during this time (Sterling et al., 1994; Sterling, 1994a). Insect larvae are fed upon more during the cool, wet season (Sterling, 1994a). The insect larvae foraged on by the aye-aye are high in water content, protein, and fat and low in lignin (Sterling et al., 1994). Canarium seeds are found to be high in fat (Sterling et al., 1994). Intsia cankers are low in protein, moderately high in fat, and high in lignin (Sterling et al., 1994). The aye-aye at Nosy Mangabe has a relatively high-roughage diet (Sterling et al., 1994). The nectar from Ravenala madagascariensis provides the aye-aye with a high-energy food source during the hot, wet season (Sterling et al., 1994). The aye-aye does not have a hand preference when foraging (Feistner et al., 1994).

Coconut is usually foraged upon when still on the tree, and the aye-aye will usually choose unripe nuts (Petter and Petter, 1967; Petter, 1977). Unripe coconuts have more juice and the pulp is not as thick (Petter and Petter, 1967; Petter, 1977). First the aye-aye will gnaw a large area off of the fiber, then the nut will be gnawed (Petter and Petter, 1967; Petter, 1977). With its incisors the aye-aye will make a round hole 3 to 4 centimeters in diameter, which takes about 2 minutes to complete (Petter and Petter, 1967; Petter, 1977). Then the aye-aye will insert its elongated third finger and first scoop out the juice then the pulp with rapid movements towards the mouth (Petter and Petter, 1967; Petter, 1977; Winn, 1989). Almost all of the pulp is scraped out of the nut (Petter and Petter, 1967; Petter, 1977). When finished the aye-aye will leave the coconut still attached to the tree (Petter and Petter, 1967; Petter, 1977). Coconuts are commonly consumed when other fruits are not available (Petter and Petter, 1967; Petter, 1977). Eggs, mangos, and avocados are consumed in the same way as coconuts, using the third finger to scoop up the contents of the egg (Petter, 1977). When consuming eggs, the lower incisors are used to chisel a neat, circular cap (Winn, 1989). When consuming mangos and avocados, the aye-aye will use both the third and fourth digits as a spoon to scoop out the contents (Winn, 1989). This foraging behavior using the elongated third digit is learned (Winn, 1989).

Ramy nuts, Canarium madagascariensis, are fed upon in the following sequence: the nut is located (5-17 seconds), the is nut and settling down to consume it (6.5 seconds on average), the pulp is scraped off and the hard shell is gnawed at (49 second average), and the contents are extracted and eaten (36 second average) (Iwano and Iwakawa, 1988). Aye-ayes will bite off nuts from the tip of a branch (Iwano and Iwakawa, 1988). The pulp is scraped off with the incisors (Iwano and Iwakawa, 1988). The contents of the nut are extracted using the third digit (Iwano and Iwakawa, 1988). When extracting, the individual may change hands to extract (Iwano and Iwakawa, 1988). Holes are always gnawed into the large chambers of the nut rather than the smaller chambers (Iwano and Iwakawa, 1988).

Nectar from the traveller's tree is also collected using the third digit (Ancrenaz et al., 1994). An aye-aye will detach the flower with one hand, and then with another, remove the nectar found at the base of the flower with the third digit (Ancrenaz et al., 1994). The nectar is collected quickly from the flower to the mouth where the nectar is licked by the individual (Ancrenaz et al., 1994). The flower is thrown away after it has been depleted of nectar (Ancrenaz et al., 1994). Sometimes an individual will change hands when collecting nectar (Ancrenaz et al., 1994). An individual will spend hours in one tree, alternating between feeding and resting (Ancrenaz et al., 1994).

The aye-aye uses its elongated and thin middle digit to locate insects in trees (Milliken et al., 1991). Examples of trees that the aye-aye gnaws into for insect larvae are Eugenia sp., Dombeya sp., and Protorhus ditimena (Ganzhorn and Rabesoa, 1986). The aye-aye uses the digit to tap on a tree and locate a mine where an insect might be located or has burrowed through (Erickson, 1995a, 1994). When insects burrow in the trees they leave wood chips in their wake, frass, and aye-ayes have been shown to discriminate in the mine in area where there is frass and there is not frass (Erickson, 1998). Areas without frass have a greater chance of having an insect larva (Erickson, 1998). When it locates a cavity it will anchor the upper incisors into the wood and then gnaw away at the wood with the lower incisors to make a pit (Erickson, 1995a, 1994). Aye-ayes make pits that are up to 54mm deep and more than 146 cc in volume (Erickson, 1995a). These pits, or excavations, are distributed in a strategic pattern (Erickson, 1995b). Erickson (1995a) found that while most of these excavations did open into where the insects are found, many were ended blindly. The aye-aye will then use the elongated third digit to extract the larvae from the pit (Erickson, 1994). The larvae were not skewered, but either rested on the nail and brought out or the larvae would pinch the finger nail with the mandibles (Erickson, 1994). The distal phalanx of the third finger may bend as much as 30 degrees towards the dorsal side of the hand, which allows maneuverability in extracting a larva out of a cavity (Milliken et al., 1991). The most common insects sought after by the aye-aye are the larvae of longhorn beetles (Family Cerambycidae) but other beetles are eaten when found (Erickson, 1995a, 1994). The long time it takes to find the insect larva is offset by that most larvae are large and nutritious (Erickson, 1995b). Percussive foraging is first seen performed by the infant at around 10 weeks of age (Feistner and Ashbourne, 1994). At first the tapping is slow and clumsy, but with practice, the infant becomes more proficient (Feistner and Ashbourne, 1994). Infants will use the tapping in an investigatory sense as opposed to the searching for food and exploration that adults use the tapping, or percussive foraging, behavior (Winn, 1994b). Aye-ayes may forage for insects in bamboos, ochlandra capitata, also (Duckworth, 1993).

In captivity it was found that when in a feeding posture the aye-aye will use medium-sized and smaller supports (Curtis, 1992). This species was to forage on the floor a third of the time when observed in captivity (Curtis, 1992). The aye-aye was found to hide coconuts in captivity (Iwano, 1991a). The third digit is used for tapping and scooping when foraging and the fourth digit is just used for scooping food when foraging (Iwano, 1991a). It was found that ramy, Canarium spp., nuts take about 102 seconds to consume on average (Iwano, 1991a).

The aye-aye may occupy the niche filled by woodpeckers in other habitats with similar insects (Erickson, 1994; Petter, 1977; Cartmill, 1974). Woodpeckers are lacking on Madagascar. On New Guinea, the striped possum, Dactylopsila trivirgata, also forages in the same manner as the aye-aye where woodpeckers are also absent (Erickson, 1994; Sterling, 1994a). The aye-aye may have evolved the unique foraging patterns and the elongated third digit to exploit insects that other animals could not exploit (Erickson, 1994). The aye-aye also may be considered to fill a squirrel-like niche because of the lack of squirrels on Madagascar (Sterling, 1994a; Iwano and Iwakawa, 1988). There are nuts that the aye-aye can exploit that nonrodents are unable to exploit (Sterling, 1994a). Also Iwano and Iwakawa (1988) propose that ramy nuts are one of the preferred food sources and insect larvae are secondary to nuts. The aye-ayes do feed on foods that are abundant but difficult to harvest without some kind of morphological specialization (Sterling, 1994a).

The aye-aye is an arboreal and a nocturnal mammal. Ancrenaz et al. (1994) found that the aye-aye will spend most of its time in the two highest levels of the forest canopy. The lower levels of the forest are mainly used to move from one group of trees to another (Ancrenaz et al., 1994). Most of the activity occurs on oblique supports that are 3 centimeters or less in diameter (Ancrenaz et al., 1994). The aye-aye will leave its nest at nightfall (Petter and Petter, 1967; Petter, 1977). After leaving the nest, an individual may hang by three limbs and groom itself with the remaining limb (Petter and Petter, 1967). Then an individual may repair its nest (Petter and Petter, 1967). Foraging for food will occur after nest repair (Petter and Petter, 1967). The male aye-aye has a home range size that is 3-6 times greater than that for the female (Sterling, 1993). Resting in captivity has been found to account for 50% of the aye-aye's activity except for in the month of November (Iwano, 1991b).

This species builds nests that are located in tall trees or near important food sources (Petter and Petter, 1967). The nests are often built high in the crowns of trees (Ancrenaz et al., 1994; Andriamasimanana, 1994). Nests have been found in Terminalia catappa, Afzelia bijuga, Trachylobium verrucosum, mango trees (Mangifera), coconut trees (Cocos nucifera), litchi trees, and clove trees (Eugenia caryophyllus) (Petter, 1977; Ancrenaz et al., 1994). The aye-aye has also been found to construct nests in ferns attached to vertical trunks (Petter, 1977). The aye-aye will build the nest in a strong fork of the tree or in a dense tangle of lianas that is in the general shape of a bowl (Petter and Petter, 1967). The frame is built with twigs taken from the nest tree or from neighboring trees (Petter and Petter, 1967). The twigs are woven between the branches of the fork, and the roof is made from twigs laid flat on top (Petter and Petter, 1967). Sixty twigs may be used in constructing a nest (Petter, 1977). The bottom of the nest is covered in a thick layer of shredded leaves, and the interior can only hold one individual (Petter and Petter, 1967). Although two adult male aye-ayes have been found to share a nest (Sterling, 1993). The opening of the nest is usually 15 centimeters in diameter and is located on the side (Petter, 1977). The foliage used in nests is primarily of litchis (Petter and Petter, 1967). Nests can be inhabited for consecutive days and may be abandoned and habited again (Petter and Petter, 1967; Ancrenaz et al., 1994). Individuals will never use a nest at night (Ancrenaz et al., 1994). Nests that are abandoned may be utilized by ants (Hymenoptera), rodents (Rodentia), or the prosimian Cheirogaleus major (Petter and Petter, 1967). Andriamasimanana (1994) found that individuals will urine-mark around the nest area, with the female marking on the ground and males marking on oblique branches.

Aye-ayes will use their third and fourth digits when self-grooming (Iwano, 1991a). Self-grooming usually occurs suspended by both feet from a support (Winn, 1989). When self-grooming suspended by the feet, medium to large horizontal branches are utilized (Ancrenaz et al., 1994). The third digit is used for the grooming of the eyes, ears, and nose (Winn, 1989). The aye-aye spends a lot of time cleaning its third digit (finger) (Winn, 1989). Usually during the night there are two or three bouts of self-grooming that last about 30 minutes each (Ancrenaz et al., 1994). Self-grooming by the infant consists of brushing the hand across the head and ears, and self-grooming increases when the infant acquires a greater degree of manual dexterity (Feistner and Ashbourne, 1994). This behavior starts to occur at 3 months of age (Winn, 1994b). Winn (1994b) found that infant aye-ayes at 104 days of age would start clumsily cleaning the elongated third finger. Self-grooming increases as the maternal care decreases in the young aye-aye (Winn, 1994b). Young aye-ayes will start gnawing at around 10 weeks, this serving to hone and wear down the continuously growing incisors (Feistner and Ashbourne, 1994).

The main predator of the aye-aye is humans, Homo sapiens, who will kill them for meat and for superstition (Simons and Meyers, 2001). For many villagers of Madagascar the aye-aye is considered a bad omen (Rowe, 1996; Garbutt, 1999). Farmers will also kill aye-ayes for raiding crops (Garbutt, 1999).

The aye-aye mainly moves quadrupedally through the crown of forests (Fleagle, 1988; Iwano, 1991b). Of the types of locomotion used, quadrupedalism was found to be used 60% of the time, climbing 14%, tail-first descent 1%, head-first 9%, bridging 7%, leaping 6%, and suspensory locomotion 2% of the time (Curtis and Feistner, 1994). When the aye-aye climbs a vertical trunk, it moves by making rapid and successive leaps (Petter, 1977; Ancrenaz et al., 1994). During climbing all appendages are gripping the trunk at the same time (Petter, 1977). The head-first descent may be possible because of the claw-like nails and the strong, opposable hallux of the aye-aye (Curtis and Feistner, 1994). During head-first descent, the aye-aye does not alter the hand position and uses either full or partial finger curling (Krakauer et al., 2001). Finger curling is necessary to reduce the stress on the elongated fingers (Krakauer et al., 2001; Winn, 1989). When descending head-first aye-ayes will also reduce the body angle in relation to the substrate to reduce the stress on the fingers (Krakauer et al., 2001). When an individual leaps to the ground it will land on all four legs (Petter, 1977). When walking on the ground the fingers do not touch the ground and pressure instead is put on the palm (Petter, 1977). When traveling in captivity the aye-aye tends to use medium-sized supports, and the supports tend to be horizontal or oblique in angle (Curtis, 1992). Ancrenaz et al. (1994) found that horizontal supports are favored when traveling, and that the supports are generally small in size.

In the infant branch climbing occurs from 9-12 weeks, head-first descent and bipedal suspension at 10 weeks, quadrupedal jumps and pounces at 11 weeks, quadrupedal walking on the ground at 12 weeks, leaping from 12-16 weeks, running on a branch at 28 weeks, and running on the ground at 34 weeks (Feistner and Ashbourne, 1994; Winn, 1994b). The infant at first can only climb along the underside of a branch; unable to keep it's balance (Feistner and Ashbourne, 1994). Suspension by the infant beneath a branch and by the feet is found to occur in the third month of age (Winn, 1994b). Winn (1994b) found that the infant did not display full adult locomotory patterns until 9 months of age.

This species is solitary, and makes nests that are about 9 meters apart from one another. The home ranges of males have a high degree of overlap, and the home ranges of females do not overlap at all (Sterling, 1993; Sterling and Richard, 1995; Ancrenaz et al., 1994). Male home ranges overlap those of several females (Sterling, 1993; Sterling and Richard, 1995; Ancrenaz et al., 1994). The aye-aye has a multimale-multifemale mating system, with males showing a "scramble competition polygyny" type approach (Sterling, 1993). In captivity females are found to exert dominance over males with having priority to food resources (Rendall, 1993). Individuals were occasionally found to forage together as a unit (Sterling, 1993; Sterling and Richard, 1995). When foraging individuals will coordinate movements with vocalizations (Sterling and Richard, 1995). There is in this species strong male-male competition for females in estrus (Feistner and Taylor, 1998). Males will try to dislodge other males when they are copulating with a female (Sterling and Richard, 1995). Aggressive actions may occur when one individual attempts to enter a nest occupied by another individual (Petter, 1977). A high degree of aggression occurs between females who interact rarely (Sterling and Richard, 1995). Andriamasimanana (1994) found that in the wild female and male individuals will stay in close proximity after the birth of an infant and that the male will sometimes share food, such as coconut, with the infant.

Social play occurs between the infant and the mother and consists of play attacks, wrestling, chasing, and "peep-bo" (Feistner and Ashbourne, 1994). Mutual social play is first seen when the infant is 13 weeks of age, and the infant initiates most play bouts (Feistner and Ashbourne, 1994). Although Winn (1994b) report that the mother is active in initiating play bouts with sudden attacks or with mock lunges.

infant distress call: This call is emitted by the infant when it is separated from the mother (Winn, 1994b). This call sounds like a shrill "creee" (Winn, 1994b). This vocalization is used to express pain, distress, loss of contact, or to seek contact (Winn, 1994b). This call is also heard when social play becomes too intense (Winn, 1994b). Infants may urine mark when emitting this vocalization (Winn, 1994b).

infant aggravation call: This call is a grunt that consists of a single broadband spike followed by a low-frequency tonal component (Stanger and Macedonia, 1994). This call is thought to express aggravation (Stanger and Macedonia, 1994).

adult contact call: This call sounds like the infant distress call (Petter and Charles-Dominique, 1979). The duration of this call is from 2-3 seconds (Ancrenaz et al., 1994). The adult female version of this call is weaker, less frequent, and has an empasis on the final phase as compared to the adult male's version (Ancrenaz et al., 1994). Adults will use this call to maintain contact during the night (Ancrenaz et al., 1994). Mothers will also emit this call as a response to infant distress call (Petter and Charles-Dominique, 1979; Ancrenaz et al., 1994). Andriamasimanana (1994) reports that this call is used as an alarm or agonistic call.

mild alarm call: This call sounds like "fuff" (Winn, 1994b). Infants and adult females emit this call during episodes of mild alarm (Winn, 1994b).

severe alarm call: This call sounds like "rhon-tsit" (Winn, 1994b). The infant and adult female emits this call during situations of high alarm (Winn, 1994b). Adults with also show pilo-erection and a threat display during this vocalization (Winn, 1994b). Stanger and Macedonia (1994) refer to this vocalization as sneeze.

hai-hai call: This call is loud and two-part in nature (Stanger and Macedonia, 1994). This vocalization is given when individuals flee out of their during capture attempts (Stanger and Macedonia, 1994).

scream: This call is described as largely tonal and high in amplitude (Stanger and Macedonia, 1994). This call is often preceded by an upsweeping introductory note (Stanger and Macedonia, 1994). This call is heard during capture and during aggressive situations just prior to biting (Stanger and Macedonia, 1994). This call is sometimes to the alarm call of Avahi laniger (Stanger and Macedonia, 1994).

plea: This call is a variable tonal vocalization in structure and may be a milder arousal version of scream (Stanger and Macedonia, 1994). This call is heard when one individual is startled by the sudden appearance of another (Stanger and Macedonia, 1994). In captivity this call is heard when individual are struggling to free themselves from restraints (Stanger and Macedonia, 1994). This call may communicate protest on the part of the sender rather than fear or alarm (Stanger and Macedonia, 1994).

whimper: This call is composed of 3-4 brief tonal calls with descending frequency sweeps (Stanger and Macedonia, 1994). These sequences are repeated over time (Stanger and Macedonia, 1994). In captivity this vocalization was heard in the context food competition over preferred food items (Stanger and Macedonia, 1994). In the wild this call was heard by young individuals who were attempting to forage in a tree that already contained an older conspecific and also by females who wished to terminate copulation (Stanger and Macedonia, 1994).

contentment vocalization: This call is emitted by individuals when feeding on a favored food item or when grooming after copulation (Winn, 1994b). This call sounds like "hoo-hoo" (Winn, 1994b). Infants will give this call when suckling from the mother or when being groomed by the mother (Winn, 1994b).

From a captive study it was found that aye-ayes are able to distinguish between the scents of conspecifics from differing age-sex classes (Price and Feistner, 1994).

cheek marking: This is when an individual will mark a substrate with the cheeks while moving slowly (Winn, 1994a). Branches, trunks, and other objects are marked in this way (Winn, 1994a). The front teeth are forcefully pressed against the substrate, which leaves saliva on the substrate (Winn, 1994a). This behavior is often done with anogenital marking (Winn, 1994a). This behavior is most often seen during maximal swelling of the female's labia (Winn, 1994a).

anogenital marking: This is when an individual will rub the vulva or scrotum and the perineum on a substrate while slowly crawling (Winn, 1994a). This behavior is done on a branch while clasping it with both hands and feet, with the body pulled parallel to the branch (Winn, 1994a). The mark is usually 20-50 centimeters long (Winn, 1994a). This behavior is often done with cheek marking (Winn, 1994a). This behavior is most often seen during maximal swelling of the female's labia (Winn, 1994a).

urine marking: This is when an individual will have the hindquarters flat and the upper portion of the body in a vertical position and leave a urine trail along the substrate (Winn, 1994a). The urine trail is about 50 centimeters in length (Winn, 1994a). This behavior is most often seen during maximal swelling of the female's labia (Winn, 1994a).

chest marking: This behavior is performed more frequently by the adult male (Winn, 1994a). This is where an individual will press the chest against a substrate, clasping the substrate with all four limbs to provide more pressure (Winn, 1994a). This behavior is often accompanied by cheek marking and/or anogenital marking (Winn, 1994a).

threat display: This is when an individual will move with a ponderous gait that involves the exaggerated raising of the feet (Winn, 1994b). This is performed as a prelude to an attack (Winn, 1994b). Severe alarm call accompanies this display (Winn, 1994b). This behavior was first seen to occur in a youngster at 62 days of age (Winn, 1994b).

social grooming: This is when one individual removes dead skin or parasites from another individual. Infants will start grooming their mothers at 11 weeks, and mutual grooming occurs in this species (Feistner and Ashbourne, 1994). Naso-anogenital contact will precede this behavior when the mother grooms her infant (Winn, 1994b). In captivity males were found to groom females far more than females groom males (Rendall, 1993).

naso-anogenital contact: This behavior is performed by the adult female towards her infant (Winn, 1994b). This behavior precedes social grooming (Winn, 1994b). The mother was found not to perform this behavior after the infant reaches 5 months of age (Winn, 1994b).

This species gives birth to a single offspring. During estrus of the female, the labia swells, reddens, and becomes very moist (Winn, 1994a; Beattie et al., 1992). The vulva is about 2.5 centimeters in diameter during estrus and extends about 2.5 centimeters from the body (Carroll and Beattie, 1993). The clitoris is slightly raised, has an oblong shape, and is dark rosy pink in color during estrus (Carroll and Beattie, 1993). Maximum swelling of the labia during estrus can last for about 8.8 days, and the estrus cycle has a mean length of 49.8 days (Winn, 1994a). In captivity, females were found to be sexually active 6-7 months of the year (Winn, 1994a). It is suggested that this species does not have a specific reproductive period, they will copulate during any time of the year (Sterling, 1992, 1994b).

During aye-aye copulation the male will approach the female from behind and try to grasp her in the dorsal position (Winn, 1994a). Naso-anogenital contact and nose-to-nose sniffing will usually precede the grasp attempt (Beattie et al., 1992). In captivity it was found that mountings were more successful when done on a branch (Winn, 1994a; Beattie et al., 1992). Preceding the mountings on a branch, the male and female will embrace each other while suspended from the branch by the feet (Winn, 1994a). The male and female will also gently nibble on each other's faces (Winn, 1994a). The copulation posture is where the female is hanging below a branch by the hands and feet with the male in a dorso-ventral position below her (Winn, 1994a; Feistner and Taylor, 1998; Beattie et al., 1992). The male will grasp the ankles of the female with his hindfeet and the arms are clasped around the thorax (Winn, 1994a). The male will bite the female on the back when in the copulation posture (Winn, 1994a). The male will insert the penis using pelvic thrusts, and the female will be in a stable position looking over her shoulder towards the male (Winn, 1994a). The male will then begin with rapid thrusts that eventually become slower and deeper, lasting for 5 minutes with one thrust per second (Winn, 1994a). Feistner and Taylor (1998) report that aye-aye intromission and thrusting lasts for 55-65 minutes for captive individuals at the Jersey Wildlife Preservation Trust. Sterling (1993) also found that thrusting and intromission lasted from 55-65 minutes. After ejaculation, the male will dismount and move to another level of branches (Winn, 1994a). Males and females will sometimes groom each other after copulating, and the female grooms her vulva with her elongated third digit (Winn, 1994a; Beattie et al., 1992). Females have been found to mate with more than one male in a day in the wild (Sterling, 1993).

In captivity the birth of an infant occurred inside a nest-box at 157 days post mating (Beattie et al., 1992). After giving birth the female will remain in the nest-box only coming out to feed (Beattie et al., 1992).

Infants remain in the nest for about two months before emerging (Winn, 1994b). Two suckling postures are found in this species: a standing one and a reclined one (Winn, 1994b, 1989). In the standing posture the infant will butt the inguinal region of the mother prior to suckling (Winn, 1994b). In the reclined posture both the mother and the infant are in a reclined position (Winn, 1994b). Suckling begins to decline at 118 days, with weaning occurring at 170 days (Winn, 1994b, 1989). Infants start eating solid food at about 14 weeks (Feistner and Ashbourne, 1994). Infants start begging for food from their mothers at 16 weeks (Feistner and Ashbourne, 1994). Andriamasimanana (1994) found that in the wild female and male individuals will stay in close proximity after the birth of an infant and that the male will sometimes share food, such as coconut, with the infant. Females in the wild were found not to forage far for food from the infant; one female did not forage more than a 50-meter radius from her infant (Andriamasimanana, 1994). Mothers will carry infants in their mouths sometimes if the infant emits infant distress call (Carroll and Haring, 1994).

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