Lesser Hedgehog Tenrec

Maximum longevity: 19 years (captivity) Observations: In the wild, they become sexually mature after their first winter's hibernation, though females may conceive at six months of age in captivity. One captive specimen lived for 19 years (Richard Weigl 2005).

Echinops telfairi (Martin, 1838)

Physical Description

Although superficially similar to Setifer setosus, the dental formula of Echinops is unique and exhibits the most profound reduction in tooth number within the family Tenrecidae. The dental formula is 3/3 1/1 2/2 2/2 with a total of 32 teeth. In total length, Echinops is slightly smaller than Setifer ranging from 140 to 180 mm. Weights in captivity range from 110 to 250 grams depending on whether the animal is in full condition or if it has recently emerged from torpor. There are no profound external differences between the sexes. Since the animals possess a cloaca, sex determination is accomplished by manually expressing the phallus. The males, however, do appear to have a broader head with a slightly greater distance between the eyes when viewed frontally. Color variation has been noted in Echinops and several subspecies have been proposed (Grandidier and Petit, 1932); however, it is to be noted that within a given population one may find individuals exhibiting extreme variations in color from a pale, almost white condition to a very dark body color resulting from more intense melanin deposition in the annular bands of the quills. The laboratory population captured by Gould showed such variation and we are led to conclude that within a given population a condition of genetic polymorphism occurs and the ratio of pale individuals might indicate that a simple Mendelian recessive is responsible for the difference in color (see Figure 35).

Distribution and Habitat

Echinops is confined to the more arid southwestern portion of Madagascar and has been collected at Morandava and Tulear. The animals appear to den in tree cavities and may be taken on the ground under logs, at the base of trees, or off the ground in hollow tree cavities of limbs and trunks (see Gould and Eisenberg, 1966). The distribution of their nests implies that they have considerable arboreal ability and this is indeed the case. Observations in captivity would indicate that the animals can forage for insects in trees as well as on the ground.

Activity and Thermoregulation

The extensive studies of Herter (1962b) indicate an endogenous diel rhythmicity in metabolic rate. This is reflected by a decline in internal temperature with cloacal temperatures reaching a minimum slightly before noon and beginning to increase coupled with an increase in breathing frequency until the maximum cloacal temperature is reached at approximately midnight.

The degree of oscillation in body temperature is in part a function of the ambient temperature. Since Echinops comes from an area of Madagascar which is subject to extremes in seasonal temperature, we might conclude that a given population could exhibit synchronized torpor on an annual basis. This is probably quite adaptive since the abundance of insect prey may be influenced by temperature and seasonal aridity. Since both of these factors are manifest in an extreme condition in their native habitat, it seems safe to conclude that an annual season of torpor is shown. For example, in the laboratories at the National Zoological Park during the beginning of the annual decline in activity over an ambient temperature range of 23° to 26.8° C., our laboratory population exhibited a morning cloacal temperature range from 24° to 28° C. and a late afternoon range from 27.5° to 30.7° C. Laboratory population synchrony was much more pronounced in Echinops than was the case in Setifer.

The Annual Cycle and Reproduction

If the propensity to assume torpor is indeed seasonal in the wild, we may conclude that the season of reproduction is likewise synchronized. In the laboratory, the animals continued to show from 1963 to 1966 an annual tendency to decline in weight to a minimum of approximately 110 grams and then commence feeding and rise to maximum weight again. During 1963, 1964, and 1965, minimum weights were achieved in September with maxima approximated in May and June. Under this rhythm, births took place in the months of November, December, and January. In 1966 and 1967 we attempted to monitor this rhythm by depriving the animals of food during the months of July, August, and September. In this way, maximum weights were maintained in April, May, and June, and minimums were achieved in January and February. This allowed us to control reproduction and litters were produced in April and May of 1966 and in June of 1967. It would appear, then, that feeding and activity do operate in part on an endogenous rhythm but can be modulated by environmental conditions. One environmental condition is to lower the ambient temperature which induces prolonged torpor; the other is to deprive the animals of food.

Gestation is approximately 66 days. This means that if animals emerge from torpor in the wild in September, one would anticipate that, after an initial feeding phase, breeding would take place in early October and litters would tend to be produced in December or January.

Feeding Habits

The animals will take a variety of animal food including insects, baby mice, and chopped horse meat. A detailed preference analysis was published by Herter (1963a).

Ethological Studies

Previous data concerning the behavior of Echinops has been published by Herter (1962b, 1963a), Honegger and Noth (1966), and Gould and Eisenberg (1966). Because of the existing data, we will use this section as a summary rather than a detailed redescription.

GENERAL MAINTENANCE BEHAVIOR

Locomotion.—The animal moves with a typical crossed extension pattern. During rapid locomotion it can rise on its toes and the heel does not contact the substrate. The animal moves ably in the trees or on a plane surface (see photographs in Honegger and Noth, 1966) and the tail serves as a brace. Observations on its swimming behavior are included in Herter (1964).

Exploration and utilization of living space.—The animals are strongly nocturnal. At approximately 1900 hours the animals commence activity and begin leaving their dens to forage for food. As noted before, they climb spontaneously and well. During climbing the animals are able to grip rough bark while continuously sniffing and nosing the substrate. Upon approaching junctures of limbs, the animals will pause to test the air and may lick their lips. This produces a slight clicking sound which apparently is involved in their echolocating ability (see Gould, 1965).

Rest and sleep.—The animal typically sleeps in a curled posture with its head tucked ventrad. At high temperatures the animal may recline with the body axis fully extended.

Marking.—In captivity the feces and urine may be deposited at specific points in the cage. Feces and urine are implicated in chemical communication (see p. 62). When exploring in a new area, the animals have been observed to depress the cloacal region and drag it on the substrate; as noted for the other forms, this has been described as the “perineal drag.”

Echinops exhibits a very special self-marking movement that has been described by Eibl-Eibesfeldt (1965) and Gould and Eisenberg (1966). In the latter publication this movement is compared and contrasted with an analogous behavior pattern in the true hedgehog, Erinaceus. This scent marking pattern involves approaching a foreign chemical substance, sniffing or licking it, lifting the head, and salivating slightly. Then one forepaw is rubbed rhythmically in the chemical substance, and while rising partially on its hind legs the tenrec then turns to one side to spread the chemical substance with its forepaw on its side quills. As has been noted before, this spreading of foreign odors on the quills is also exhibited by the hedgehog, Erinaceus europaeus, but in the latter case it does not involve the use of the forepaw but rather the foreign chemical and saliva are spread with the hedgehog's tongue (Gould and Eisenberg, 1966).

Care of the body surface.—As noted with Setifer, the animal grooms its spines primarily by scratching. It will lick its cloacal region and ventrum. Echinops will exhibit the face wash by sitting upright and employing the forepaws to stroke simultaneously on either side of the head (see also Setifer, p. 53, and Microgale, p. 34). The washing movements occur alone or in conjunction with the self-marking movement described in the previous section.

Nest building.—This behavior is highly developed. Leaves and dry grasses will be transported in the mouth to the burrow and placed therein to form a cup.

Prey-catching and feeding.—Prey-catching behavior involves orientation to the prey object, such as an insect, sniffing and seizing it with the mouth. There is little involvement of the forepaws in the capture of prey, but the forepaws may be used to brush food and align it if, for example, an insect is seized crosswise in the mouth.

Defensive and offensive behavior.—As noted with Setifer, Echinops can roll itself into an impregnable spiny ball. Various degrees of spinal erection may by displayed during arousal. The brow may be rolled forward and the animal will switch its head from side to side or buck up and down attempting to drive the spines of the head into an enemy. The tendency to exhibit the gape reaction or to bite is reduced in Echinops compared with Setifer. The crunch sound is strongly associated with the bucking response as in Setifer.

SOCIAL BEHAVIOR

Communication.—As noted with Setifer visual communication is probably negligible. Tactile, chemical, and auditory signals predominate during their interaction.

During an encounter in a neutral arena, two strange animals will show exploratory behavior. Tongue clicks may be produced at this time and are implicated in echo-location (Gould, 1965); however, such potential signals may serve in locating a conspecific. A mildly disturbed animal may show “brow rolling” to a conspecific while producing a train of discrete “putt-putt-putt” sounds similar to those produced by Setifer. The bucking, defense behavior is accompanied by the “crunch” sound. The animal may hiss repeatedly when rolled in a ball or when retreating with the brow rolled forward.

In addition to these agonistic sounds, the animals produce a series of squeaks which grade in intensity and duration. Mildly disturbed young produce a high peeping sound; the adult produces sounds ranging from this infant sound to very distinct “chirps.” As with Setifer the chirps are produced by females during the initial phases of courtship and mating (see Table 6).

It should be noted that during courtship behavior and marking, Echinops will frequently show a rhythmic motion of its body musculature. This movement produces a slight abrasion of the dorsolateral quills, one against another, with a very low sound being produced. The exact significance of this sound and its context are not clearly understood.

Tactile communication occurs during nose to ear, nose to body, nose to anal region, or when rubbing against one another, or crawling over and under.

Chemical communication is implied by the locus specificity of defecation and the spreading of scents on the quills (see p. 60). In addition the males often secrete a white substance around the eye as described for Setifer.

The encounter and mating.—Male-male behavior in Echinops usually involves avoidance or actual fights. Males can be extremely aggressive to one another and, during the process of mutually sniffing each other's sides with the body axes oriented in the opposite direction, they may begin to butt one another and attempt to bite each other's flanks. Persecution by a dominant male will eventually result in the subordinate rolling completely into a ball or fleeing.

Interaction between males and females was studied intensively. During an encounter between a male and a female, the female would often move away and defecate and/or urinate. The male would persistently follow and sniff her trail. Frequently, the animals would make contact Contact was generally initiated by a male, approaching and sniffing the female's side and then passing by her while rubbing his body the length of her side. The male may pause to sniff her ear and, if the female were receptive, mating would take place. The following protocols are offered as examples:

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Mating test with female unreceptive; male had been introduced to female's cage, 3 January 1966, 1500 hours: Male approaches, lowers head with spines erect and butts female in the side. Female turns away. Female moves to her box; male follows. Female stops; male sniffs her around the face and ear. Female turns her side toward him with spines erect. Female enters her box; male follows and attempts to mount. Male mounts gripping with his forelegs and the female arches her back, turns the tip of her nose up and with half open mouth exposes her teeth. The female emits a loud chirp during the mount and the male releases the female. The animals break apart with male leaving.

Female leaves her nest and male approaches. They encounter nose to nose. Female exhibits a half open mouth; male moves to one side and noses the female's ear. Male attempts to mount; female chirps. Male dismounts and moves away. A repeat with the male approaching nose to nose; male nose to female's ear, then attempts to mount Female chirps; male continues with mount and grips female's spines in the middle of her back with his mouth. Female will turn and bite at his flank. Male grips female's flanks with his hind legs while working his cloaca ventrad. Male emits a sustained puffing while female continues to chirp. Female pulls away. Encounter discontinued.

Mating test with female receptive. Male introduced to female's cage, 31 December 1965: Female out exploring. Male begins following; female defecates; male pauses to sniff then approaches female, touches nose to side and passes along her body rubbing his side against her. Female moves away to her box, male follows, pausing to sniff the box. Then he enters the box, exhibits a nose to her ear. He attempts to mount and the female shakes her head.

One hour later, the male approaches the female who urinates and defecates. He attempts to mount, and noses her ear. The female moves away; he follows. Ten minutes later, the male mounts again, while the female raises her tail. Male slides backwards attempting intromission. The male, preceding intromission, will attempt to scratch at the cloacal area of the female with his hind foot. Male continues mount and finally relaxes grip while the female remains motionless. Copulation is terminated after a total of 18 minutes mount with thrusting. Male initiates exploration after a rest period of approximately 17 minutes while the female remains in her box.

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We offer the following comments: Note the similarity to the mating ritual in Setifer including the prolonged mount, genital stimulation of the female by the male employing the hind foot, the neck grip of the male in seizing the spines of the female at her nape, the initial contact involving nose to ear and face, and nose to body. Finally the chirping of the female during the initial phases of mating is almost identical to Setifer. We would further like to call to the reader's attention the fact that in Setifer and Echinops there is a tendency for mating to take place in the female's nest box or a suitable cavity. One feature not noted in the protocol but noted in others is the fact that the male generally licks his genitalia at the conclusion of a long mount.

PARENTAL CARE

Preceding the birth of the young, the female indulges in considerable nest building behavior. The retrieval of nesting material persists throughout the first week in the rearing phase. Nest defense by the female increases profoundly during lactation, and she will utter the putt-putt sound if disturbed and attempt to bite. The female will retrieve the young if they are displaced from the nest, apparently in response to the peeping call that the young produce when mildly disturbed. The female will position herself over the young through lactation and, as the young mature, she may lie on one side during lactation. During the early phases of rearing, the female will lick the young especially in the area of the genitalia. Further comments on parental care are included in Gould and Eisenberg, 1966.


ONTOGENY OF BEHAVIOR

Complete ontogeny of behavior has been described by Gould and Eisenberg, 1966. We reiterate briefly the process. At birth the young Echinops are nearly naked. The auditory meatus and eyes are closed. The animals can locomote forward with poor hind limb coordination. The degree of spinescence at birth is variable but in general the tips of the spines are protruding through the skin; however, at this time the spines are very soft and hair-like. The animals can right themselves when placed on their backs. At this age the animals will roll into a ball when disturbed. Eye opening occurs between 7 and 9 days of age. At 10 days of age, the young begin to follow the female to the entrance of the nest. The auditory meatus opens at around 14 to 16 days of age. At this time they can locomote very well holding the ventrum off the substrate. The young begin to take solid food at around 2 weeks of age; weaning begins at approximately 18 days. Nursing in captivity may persist until the animals are 4 weeks old but they have been taking solid food as a supplement since approximately 3 weeks of age. Growth curves are presented in Figures 39 and 40.

SOCIAL ORGANIZATION

Most of the generalizations in this section are, based on observations in captivity. It would appear that Echinops forages alone except for the female-young unit. This unit persists until the youngsters are approximately 4 to 5 weeks of age. Apparently the young accompany the female on her foraging expeditions from the age of about 3 weeks on. On 28 January 1967 near Morondava, an adult female (total length 151 mm) and 2 juveniles (total length 124 mm) were collected from the same tree hollow. Some initial following tendency is exhibited by the young as early as 2 weeks of age. Echinops would appear to exhibit a mild degree of social tolerance and Gould and Eisenberg (1966) have noted that more man one individual may be found during the period of torpor. Three Echinops were found hibernating alone and two groups of two each were discovered (Figure 41).

The lesser hedgehog tenrec (Echinops telfairi) is a species of mammal in the family Tenrecidae. It is the only species in the genus Echinops and is named in honour of Charles Telfair. It is endemic to Madagascar. Its natural habitats are subtropical or tropical dry forests, shrubland, and shrubland and dry savanna.