Hispaniolan solenodon

Solenodon paradoxus

TAXONOMY

Solenodon paradoxus Brandt, 1833, Dominican Republic. OTHER COMMON NAMES

English: Haitian solenodon; French: Solenodonte d'Haiti; German: Dominikanischer Schlitzrussler, Haiti-Schlitzrussler; Haitian French: Nez longue; Spanish: Solenodonte haitiano.

PHYSICAL CHARACTERISTICS Individuals resemble very large shrews. An adult weighs up to 2.4 lb (1,100 g). Its combined head and body length ranges 11-12 in (28-32.5 cm), and the tail length is 7-10 in (17.5-25.5 cm).

There are five fingers and five toes, for, respectively, the forepaws and hind-

paws, and all digits are equipped with large, strong claws, although the forelimbs are more powerfully muscled than the hindlimbs, and the forepaws are bigger. The underfur is short and dense, overlain by a coarser secondary coat. The forehead is sparsely covered with hair, while the ears, legs, snout, and scaly, rat-like tail are nearly hairless. The snout sprouts long vibrissae, or sensory whiskers, along its length.

Solenodon paradoxus

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Solenodon paradoxus

Fur color ranges from brown through reddish brown to yellowish brown on the upper, dorsal body, with a lighter shade on the underside. A light-colored, roughly rectangular spot in the fur of the nape changes slightly in size and shape throughout the animal's life.

A signature characteristic of Solenodon paradoxusis the os proboscis, a small, round bone, located at the tip of the rostrum (bones of the nasal region), and which holds the proximal end of the cartilaginous support for the long snout. The os proboscis articulates with the rostrum in a ball-and-socket joint, a most unusual feature among the vertebrates. The Cuban solen-odon lacks this feature.

DISTRIBUTION

The Caribbean island of Hispaniola; in the Dominican Republic, in several forested areas; in Haiti, only in the extreme southwest.

HABITAT

Montane tropical rainforest. The animals may sometimes settle in scrub, or near plantations.

BEHAVIOR

The Hispaniolan solenodon forages nocturnally, hiding and sleeping during the day in spaces between rocks, in hollow trees, or in networks of burrows that the animals excavate. Usually, several individuals rest together in a hollow or burrow. Captive Hispaniolan solenodons will sleep piled in heaps within their shelters.

Wild male adults, and female adults without young, are solitary when foraging, even if they share burrow space.

Field researchers have often found collections of snail shells in the burrows of wild Hispaniolan solenodons. Captive solen-odons have been observed collecting similarly small, hard objects, such as coarse chunks of peat moss and beechnut husks, and dragging them into their sleeping enclosures.

Captive solenodons show nesting activity, lining their sleeping shelters with hay, dried leaves, peat moss, and similar materials, pushing it into little heaps with their forepaws, then dragging it, backwards, with forepaws or jaws, into the nest enclosure. A pregnant female will prepare a litter nest.

Hispaniolan solenodons, in the wild or in captivity, produce a variety of vocalizations: wheezing and snuffling like hedgehogs, grunting like pigs, squeaking like guinea pigs, twittering like mice, and whimpering like young kittens. An excited or alarmed solenodon will sound off with penetrating shrieks. Mothers and their young, or mates, make bird-like contact calls, while courting individuals make repeated "pifP' noises.

Hispaniolan solenodons appear to echolocate. An individual will produce a series of high-pitched clicks when checking out a new area or encountering a strange animal. Several species of shrew (Soricidae) and tenrecs use echolocation.

Sudden high, shrill, or sharp noises will panic the animals and send them fleeing. If threatened by a rival solenodon or another species, the solenodon will first take an upright, defensive posture and warn its opponent with a loud "chirp." If fleeing the opponent is the chosen option, a Hispaniolan solenodon first runs in an erratic pattern, then crouches motionless and hides its head. This behavior may have given it a survival edge against predators, particularly birds of prey, before human settlement of Cuba and Hispaniola, but those traits work against it when dealing with introduced predators like dogs, cats, and mongooses.

FEEDING ECOLOGY AND DIET

Hispaniolan solenodons are omnivorous, generalist feeders with some emphasis on insects and spiders, while varying their fare with worms, snails, small reptiles, roots, fruits, and leaves.

A Hispaniolan soledonon forages along an erratic, winding course, probably in accordance with a food-search pattern, while using its flexible snout to root in dirt and poke into leaf litter, using smell and tactile senses to find earthworms, arthropods, or land snails, digging them out of the soil or snagging them in leaf litter. A solenodon will carefully clean the dirt from a snagged earthworm with its front paws before eating it. The animal also uses its powerful forelimbs and claws to tear into soft, rotten wood in search of resident edibles.

Hispaniolan solenodons drink water by lapping it up with their tongues, while holding the snout bent upward, then swallow it while throwing their heads back.

REPRODUCTIVE BIOLOGY

Mating behavior is common to insectivores, presumably polygamous or promiscuous. In captivity, a male introduced into a female's cage explores, and scent-marks by rubbing his anogen-ital area over objects and spots in the cage, often in areas already scent-marked by the female. As the two move closer to each other, they repeatedly make reassuring "piff" noises. Physical contact begins with nose-to-nose touching, followed by the two animals sniffing different parts of each other's body. As the male mounts, he secures his and the female's position by a neck grip on the female.

Both sexes of the Hispaniolan solenodon exude a greenish, oily fluid from scent glands in the armpits and groin. However, the amount of a female's excretions may indicate the level of arousal, while the male that can mate at any time excretes a similar fluid at a constant rate.

A female gives birth to a litter of one, two, or even three young in a nesting burrow, and she can birth two litters within a year. There is no set mating season. A mature Hispaniolan solenodon female's estrous lasts about a day, with intervals of nine to thirteen days between estrous periods. The gestation period is unknown. Individual young weigh 1.4-1.9 oz (40-55 g)

at birth, and are blind and nearly hairless, although they've grown a complete coat of fur by two weeks after birth.

The female has two teats, situated near the groin. Out of a litter of three, one will probably die, since the mother can nurse only two at a time. When seven weeks old, the nursing youngsters accompany the mother outside in her foraging by hanging fast to her teats with their jaws, being dragged along wherever she goes. This behavior, known as "teat transport," is well known among rodent species, but among the insectivores, known only in solenodons. The young are weaned after 75 days, a long time for insectivores, while the young may sometimes remain with the mother while she births and raises subsequent litters. Males do not share in parenting.

CONSERVATION STATUS

The Hispaniolan solenodon is listed as Endangered by the IUCN. The species is beset by deforestation, killing by humans who consider them pests, and by introduced house cats, dogs, and mongooses, against which the animals have little defense.

Hispaniolan solenodons sometimes nest and burrow near plantations, where the soil, made softer and more pliable by farming, makes for easier burrowing, while the plantations themselves are abundant with insects. Farmers kill solenodons, accusing them of attacking crops, when most likely the animals were foraging for insects in the fields, while the proximity to settled areas renders solenodons more vulnerable to harm from humans and introduced animals.

By 1907, the Hispaniolan solenodon had been written off as extinct, but several isolated populations have been rediscovered in Hispaniola. Of the two Hispaniolan nations, Haiti and the Dominican Republic, a 1996 survey found 5. paradoxus in both countries, although its survival isn't likely in Haiti, which has been all but completely deforested.

SIGNIFICANCE TO HUMANS

Negatively, solenodons are considered only minor nuisances when they disturb agricultural land. There are not many of them, and they are not hunted for food. They are of no direct positive significance to humanity, but more abstractly, they are conservation symbols and living studies in the evolution of primitive placental mammals and in adaptive evolution on islands. ♦

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