The Hispaniolan solenodon (Solenodon paradoxus) is one of the most unusual and ancient mammal species to be found on Earth. Along with its smaller Cuban cousin (Atopogale cubana) it belongs to the mammal family Solenodontidae. It not only represents one of the last two surviving native insectivorous mammals found in the Caribbean, but is also one of the only two remaining endemic terrestrial mammal species of Hispaniola. The species is probably best known as one of the few mammals that can secrete toxic saliva in a manner similar to snakes. The species is thought to resemble ancient mammals which existed towards the end of the age of dinosaurs, over 65 million years ago.
Unlike most of the other endemic land mammals that used to occur on Hispaniola, solenodons have managed to survive until the present day. The species was first described in 1833 by Johann Friedrich von Brandt, but our knowledge of its ecology and biology is still fairly limited due to its secretive nocturnal habits. Much of what is known can be attributed by the seminal research done by Dr. Jose Alberto Ottenwalder during the 1970s and 1980s.
One reason why solenodons may have survived is the fact that they appear to have a fairly widespread distribution across Hispaniola, and are found in a variety of forest habitats ranging from lowland dry forest through to highland pine forest (see map below for the current estimate of the species range). However, solenodon populations are highly fragmented and their range has markedly declined in extent through habitat loss. As a result the species is classified as Endangered on the IUCN Red List of Threatened Species. There is also some evidence that some populations of solenodon are quite distinct from one another, which may represent different subspecies and therefore different ‘units for conservation’.
Solenodons live in family groups usually made up of between two and four individuals, consisting of an adult pair and one or two offspring. What little we know about the breeding cycle of the species has been gained mainly by observing the few animals that have survived for any extended period of time in captivity. However, there has only ever been one recorded successful mating in captivity. Solenodons are thought to breed throughout the year and usually give birth to a single offspring, although occasionally a litter of two will be produced. The young are born naked and weighing between 80 and 100g, and they feed on their mother’s milk for up to 90 days. For the first two months the cubs may accompany their mother during her nightly searches for insect prey by clinging to her teats, which are positioned near her groin. Solenodons can probably only raise two litters in any calendar year. Subadults are thought to leave the family group at between 10 and 18 months of age. Females probably reach sexual maturity after two years. Life expectancy is unknown but is probably long; the longest surviving individual in captivity lived for just over eleven years.
Adult solenodons weigh between 800 and 1200g. They measure from 53 to 58cm from the tip of the snout to the tip of the tail. They are often described as resembling very large sturdy shrews covered in coarse hair. The hair can vary greatly in colour from white/grey through to patches of yellowish, reddish or even dark brown. The species has a thick, nearly naked tail which is mainly greyish and tends to be lighter at the base and tip. The tail makes up slightly less that half of its whole body length. Solenodons have very strong limbs which end in long sharp claws; the forelimbs are far stronger than the hind limbs, and are adapted for digging. Solenodons walk in what can only be described as a side-to-side waddle.
The solenodon’s distinctive elongated snout is joined to the skull by a unique ball-and-socket joint which provides considerable flexibility. Its most famous characteristic, the ability to secrete venom, consists of a mandibular gland which secretes venom along a grooved second lower incisor.
Solenodons are nocturnal animals which spend the daytime in a den located in a rocky outcrop, burrow or hollow tree. At night they forage for invertebrates, primarily arthropods in soil, although they may also scavenge in rotten wood. During their nightly searches they leave very distinctive conical excavations in the soil that we refer to as “nose pokes”, which are approximately 7cm wide and 7cm deep. The solenodon’s mobile snout, strong limbs and claws, and ability to envenomate their prey make them very effective invertebrate hunters. Their main prey are thought to be millipedes (Diplopoda), ground beetles (Carabidae), crickets (Gryllidae), katydids (Tettigonidae), cockroaches (Blattidae), scarab beetles (Scarabeidae), earthworms (Lumbricidae) and snails (Gastropoda). They may also be opportunistic scavengers of small vertebrates (mainly amphibians and reptiles) as well as feeding on carrion when available.
The solenodon’s size and nocturnal activity probably means that it has only three native predators. These are the barn owl (Tyto alba), stygian owl (Asio stygius) and the Hispaniolan boa (Epicrates striatus). However, the species is now killed in substantial numbers by both domesticated and feral dogs.